FEDERAL GUIDANCE REPORT NO. 14

      Radiation Protection Guidance for Diagnostic and Interventional X-Ray Procedures
                   Interagency Working Group on Medical Radiation
                        U.S. Environmental Protection Agency
                              Washington, D.C. 20460
                               DRAFT PROPOSAL

                                       DRAFT PROPOSAL

 2                                          PREFACE
 4    This document is Federal Guidance Report No. 14 (FGR 14), "Radiation Protection Guidance for
 5    Diagnostic and Interventional X-ray Procedures."  It replaces Federal Guidance Report No. 9
 6    (FGR 9) (EPA 1976), "Radiation Protection Guidance for Diagnostic X-rays," which was
 7    released in October 1976. Federal Guidance reports were initiated under the Federal Radiation
 8    Council (FRC), which was formed in 1959, through Executive Order 10831. A decade later its
 9    functions were transferred to the Administrator of the newly formed Environmental Protection
10    Agency (EPA) as part of Reorganization Plan No. 3 of 1970 (Dunn et al. 2012). Under these
11    authorities it is the responsibility of the Administrator to "advise the President with respect to
12    radiation matters, directly or indirectly affecting health, including guidance for all Federal
13    agencies in the formulation  of radiation standards and in the establishment and execution of
14    programs of cooperation with States." (EPA 2012)
16    FGR 9 provided constructive guidance on the use of diagnostic film radiography, for which there
17    was an incentive to deliver appropriate radiation doses and avoid retakes resulting from under- or
18    over-exposing the film. This report, Federal Guidance Report No. 14, focuses on the transition
19    to digital imaging,  extends the scope (to include computed tomography (CT), interventional
20    fluoroscopy, bone densitometry, and veterinary practice), and updates sections on radiology and
21    dentistry that were covered in FGR 9. It also addresses adequate imaging through justification of
22    the procedure and optimization, and features an expanded section on occupational exposure.
24    FGR 9 was developed out of a growing concern in the 1970s among medical practitioners,
25    medical physicists, and other scientists that medical uses of ionizing radiation represented a
26    significant and growing source of exposure for the U.S. population.  Human exposures to
27    medical radiation were neither controlled by law nor covered by consensus guidance.   In 1972,
28    the Federal Radiation Council released a report concluding that "...medical diagnostic radiology
29    accounts for at least 90% of the total man-made radiation dose to which the U S. population is
30    exposed."  In response, the Environmental Protection Agency (EPA) and the Department of
31    Health,  Education, and Welfare (predecessor of the Department of Health and Human Services
32    (DHHS)) developed and issued FGR 9, which was approved by President Carter (Carter 1978)
33    and published in the Federal Register on February 1, 1978.
35    According to EPA (Carter 1980), FGR 9 was the first Federal Guidance Report to provide a
36    framework for developing radiation protection programs for diagnostic uses of x-rays in
37    medicine.  It introduced into Federal guidance the concepts of:
38       •   Conducting medical x-ray studies only to obtain diagnostic information,
39       •  Limiting routine or  elective screening examinations to those with demonstrated benefit
40           over risk,
41       •   Considering possible fetal  exposures  during examinations of pregnant  or  potentially
42          pregnant patients,
43       •  Ensuring diagnostic equipment operators meet or exceed the standards of credentialing
44           organizations, and
45       •   Specifying that  standard x-ray examinations should  satisfy maximum numerical exposure
46           criteria.

                                       DRAFT PROPOSAL

48    Much of FGR 9 has stood the test of time, but other parts have become obsolete. In particular,
49    the advent of digital x-ray image acquisition has eliminated film blackening as a built-in
50    deterrent to over-exposing patients.
52    Digital imaging methodologies have improved medical care by increasing the quality of
53    diagnostic images and significantly decreasing the need for exploratory surgeries. However, in
54    some cases, the use of this newer technology was accompanied by a significant increase in
55    patient radiation dose (Seibert et al. 1996).  Some newly introduced technologies, e.g., CT,
56    yielded higher patient doses than the radiographic procedures they replaced. Finally,  increased
57    utilization of imaging studies resulted in a greater radiation dose to the population.
59    The U.S. Food and Drug Administration's (FDA) performance standards for radiation emitting
60    products address radiography, fluoroscopy,  and CT equipment, and are codified at 21 CFR Part
61    1020 (FDA 2012e). The FDA revised these performance standards in 2005, in part to address
62    some of the radiation dose issues.
64    The National Council on Radiation Protection and Measurements (NCRP) reports that medical
65    radiation exposure to the average member of the US population has increased rapidly and
66    continues to do so. Their previous estimate, based on 1970's and early 1980's data, was that
67    medical exposure accounted for 0.53 millisievert (mSv) or 53 millirem (mrem) per year, which
68    was 15% of the total annual average (per capita) dose (NCRP 1989a). Based on 2006 data, this
69    estimate was increased to 3 mSv (300 mrem) per year or 48% of the total (NCRP 2009).
71    Concerns continue to be raised about the risks associated with patients' exposure to radiation
72    from medical imaging (Amis et al. 2007; FDA 2010b; FDA 2012e). Because ionizing radiation
73    can cause damage to DNA, exposure may increase a person's lifetime risk of developing cancer.
74    Although the risk to an individual from a single exam may not itself be large, millions of exams
75    are performed each year, making radiation exposure from medical imaging an important public
76    health issue (Brenner 2007). Berrington de Gonzalez et al.  estimate that approximately 29,000
77    future cancers could be due to CT scans performed in the U.S. in 2007 (Berrington de Gonzalez
78    et al. 2009). Smith-Bindman et al. estimate that 1 in 270 women and 1 in 600 men who undergo
79    CT coronary angiography at age 40 will develop cancer from that CT scan; the risks for 20-year-
80    olds are estimated to be roughly twice as large, and those for 60-year-olds are estimated to be
81    roughly half as large (Smith-Bindman et al. 2009).  Although experts may disagree on the extent
82    of the risk of cancer from medical imaging,  there is uniform agreement that care should be taken
83    to weigh the medical necessity  of a given level of radiation exposure against the risks.
85    Given these changes in the available technologies, the reported increase in annual dose from
86    medical imaging, and concerns addressed above, EPA has decided to issue this new guidance to
87    the Federal medical community. Also, it is  suitable for use by the broader medical community.
88    This guidance creates no binding legal obligation; rather, it offers recommendations for the safe
89    and effective use of x-ray imaging modalities. Federal agencies that adopt these
90    recommendations (e.g., into orders or standard operating procedures) should, at their  discretion,
91    strengthen these statements where appropriate. EPA believes that the information contained in
92    this guidance will help users of diagnostic imaging equipment ensure that any given procedure is
93    justified for the patient being examined and that the dose delivered to that patient is optimized.


                                        DRAFT PROPOSAL

 94   EPA also believes that the information contained in this guidance will provide for radiation
 95   protection of medical workers.  The goal of radiation management is to keep patient and worker
 96   radiation doses as low as reasonably achievable consistent with the use of appropriate equipment
 97   and the imaging requirements for specific patients and specific procedures.
 99   FGR 14 establishes guidance for digital x-ray imaging that addresses protection aspects that were
100   not envisioned in FGR 9. These include:
101       •  Reference levels and dose optimization
102       •  Newer dose metrics
103       •  Introduction of positron emission tomography/computed tomography (PET/CT)
104       •  Computed tomography (CT), fluoroscopy (including interventional fluoroscopy), bone
105          densitometry, and veterinary imaging as modalities additional to radiography and
106          dentistry
108   In carrying out its federal guidance responsibilities, EPA works closely with other federal
109   agencies through its participation on the Interagency  Steering Committee on Radiation  Standards
110   (ISCORS). Moreover, EPA recognizes, as it did in 1976, that the expertise needed to make
111   sound recommendations for reducing unnecessary radiation exposure due to the medical use of
112   x-rays in diagnostic and interventional procedures resides in several agencies.  Therefore, this
113   report was prepared by the interagency Medical Work Group of the ISCORS Federal Guidance
114   Subcommittee that included physicians, medical physicists, health physicists, and other scientists
115   and health professionals from the Department of Defense, the Department of Veterans Affairs,
116   the Department of Health and Human Services, the Department of Labor, and the EPA.
118   As in FGR 9, the recommendations contained in this  report represent consensus judgment of the
119   Medical Work Group for the practice of diagnostic and interventional imaging by Federal
120   agencies.  Since the body of knowledge on both the radiation exposure and efficacy of x-ray
121   examinations is rapidly changing, comments and suggestions on the areas addressed by this
122   report will assist EPA to conduct periodic reviews and to make appropriate revisions.

                                         DRAFT PROPOSAL

132     1.  Patient safety requires that infrastructure exists for collecting, storing, and analyzing patient
133        dosimetry data. Federal facilities should plan for longitudinal tracking of patient radiation
134        doses. This planning should address the data acquisition, networking, storage, analysis, and
135        security requirements of existing and planned future diagnostic devices.
136     2.  All uses of radiation in diagnostic medical imaging should be justified and optimized.  This
137        is the responsibility of all involved providers and technologists.  Dose management begins
138        when a patient is considered for a procedure involving ionizing radiation, involves
139        equipment setup before the exam begins, and ends when any necessary radiation-related
140        follow-up is completed.
141     3.  It is strongly recommended that the justification of medical exposure for an individual
142        patient be carried out by the Referring Medical Practitioner, in consultation with the
143        Radiological Medical Practitioner when appropriate.  Each health care facility should
144        establish a formal mechanism whereby Referring Medical Practitioners have sources of
145        information available at the time of ordering regarding appropriate diagnostic imaging
146        methods to answer the clinical question and to optimize ionizing radiation dose to the
147        patient.
148     4.  For each type of examination, Federal facilities and agencies should promote the
149        development of national reference levels for use as quality assurance and quality
150        improvement tool s.
151     5.  For each type of examination there exists, within available technology, an optimal
152        combination of imaging equipment and technique factors to produce adequate images at
153        doses below the reference level. Federal facilities should evaluate each imaging system's
154        performance to optimize dose, and maintain this by establishing appropriate procedures and
155        conducting periodic monitoring.
156     6.  Agencies should only adopt screening programs that have been submitted to rigorous
157        scientific evaluation of efficacy, as has been done for mammography, to ensure that the risk
158        posed to the population screened does not outweigh the benefits in detection of disease.
159     7.  Agencies should use methods for estimating individual occupational doses based on the
160        goal of assigning accurate doses rather than overly conservative estimates of doses. NCRP
161        Report No. 122 provides recommended methods for determining effective dose (E) and
162        effective dose equivalent.  The various Federal regulatory agencies  should establish
163        consistent methods and procedures for this  purpose.

                                     DRAFT PROPOSAL

164                                TABLE OF CONTENTS


166   PREFACE                                                                      I

167   RECOMMENDATIONS FOR AGENCY ACTIONS                                IV

168   TABLES                                                                      IX


170   INTRODUCTION                                                                1


172   GENERAL PRINCIPLES OF RADIATION PROTECTION                                   4

174     Minors as Workers                                                                6
175     Embryo or Fetus of Pregnant Workers                                                 6
176     Members of the Public                                                             7

177   GENERAL CONCEPTS FOR RADIATION PROTECTION                                   7

178   RADIATION SAFETY PROGRAM                                                     8
179     Radiation Safety Officer                                                            8
180     Qualified Physicist                                                                9
181     Personnel and Area Monitoring                                                      9
182     Patient Safety                                                                  10
183     Radiation Safety Procedures for Fluoroscopy                                            10
184     Special Patient Populations                                                         11
185       Pregnant patients                                                              11
186       Pediatric patients                                                              12
187       Patients enrolled in a research protocol                                              12
188     Analysis of Risk from Radiation                                                     13
189     Informed Consent for Research Involving Radiation                                       14
190     Occupational Radiation Safety Training                                                14
191     Notification and Reporting Requirements                                              14



195   PROFESSIONALS)                                                                15
196     Qualifications to Request X-ray Examinations                                           17

198   TECHNOLOGISTS                                                                17

                                        DRAFT PROPOSAL
199      Radiological Medical Practitioners                                                      18
200      Radiologists                                                                        18
201      Medical Radiologic Technologists                                                       19

202    SCREENING AND ADMINISTRATIVE PROGRAMS                                        19
203      Chest Radiography                                                                  20
204      Mammography                                                                     20

205    REFERRAL AND SELF-REFERRAL EXAMINATIONS                                       20
206      Patients Requesting Imaging on Themselves without a Referral from a Licensed Independent Practitioner
207      (Referring Medical Practitioner)                                                        20
208      Physician Self-Referral                                                               20

209    COMMUNICATION AMONG PRACTITIONERS                                           21


211    TECHNIQUE FACTORS                                                               23

212    TESTING BY A QUALIFIED PHYSICIST                                                  24

213    EQUIPMENT FAILURE                                                                25

214    DEFICIENCY CORRECTION VERIFICATION                                             25

215    DOSIMETRY                                                                        25

216    REFERENCE LEVELS                                                                 26


218    INTRODUCTION                                                                     28

219    RADIOGRAPHY                                                                      30
220      Equipment                                                                         30
221      Testing and Quality Assurance                                                         31
222      Personnel                                                                         32
223        Radiological Medical Practitioner                                                     32
224        Technologist                                                                     32
225        Other personnel                                                                  33
226      Procedures                                                                         33

227    FLUOROSCOPY                                                                      37
228      Equipment                                                                         37
229      Testing and Quality Assurance                                                         40
230      Personnel                                                                         40
231      Procedures                                                                         42
232        Dose measurement                                                                42
23 3        Recordkeeping                                                                    42
234        Patient management                                                               43
235        Quality process                                                                   44
236        Staff safety                                                                      46

237    COMPUTED TOMOGRAPHY                                                          47
238      Equipment                                                                         48
239      Testing and Quality Assurance                                                         49


                                       DRAFT PROPOSAL
240      Personnel                                                                        49
241      Procedures                                                                       49

242   BONE DENSITOMETRY                                                             52
243      Equipment                                                                       52
244      Testing and Quality Assurance                                                        53
245      Personnel                                                                        55
246      Procedures                                                                       56

247   DENTAL                                                                          58
248      Equipment                                                                       58
249      Testing and Quality Assurance                                                        60
250      Personnel                                                                        61
251      Procedures                                                                       62

252   VETERINARY                                                                      64
253      Equipment                                                                       64
254      Testing and Quality Assurance                                                        65
255      Personnel                                                                        66
256      Procedures                                                                       66
257        Veterinary clinic setup                                                            66
258        Personal protective equipment                                                      67
259        Animal restraint                                                                67
260        Use of x-ray equipment                                                           67
261        Personal dosimetry                                                               68
262        Special procedures for portable hand-held systems                                       68

263   MEDICAL IMAGING INFORMATICS                                            69


265   GENERAL                                                                         71

266   BONE DENSITOMETRY                                                             71

267   CHILDREN AND PREGNANT WOMEN                                                 72

268   DENTISTRY                                                                       72

269   FLUOROSCOPY                                                                    72

270   VETERINARY                                                                      73

271   INFORMATICS                                                                     73

272   INFORMED CONSENT                                                               73

273   PRESCRIPTION                                                                    73

274   REFERENCE LEVELS                                                               74

275   ACRONYMS AND ABBREVIATIONS                                             75

276   GLOSSARY                                                                      78


                                 DRAFT PROPOSAL

278  MINIMAL RISK                                                        A-2

279  MINOR TO INTERMEDIATE RISK                                           A-3

280  REFERENCES                                                     REF-1


                                     DRAFT PROPOSAL
283                                       TABLES
285   Table 1. Testing Frequency of Imaging Equipment that Produces X-Rays	24
286   Table 2. Quality Assurance Measures for Film and Digital Modalities	34

                               DRAFT PROPOSAL
Department of Health and Human Services 341
L. Samuel Keith, MS, CHP, CO-CHAIR   342
John L. McCrohan, MS (retired)
Donald L. Miller, MD, FSIR FACR
Petro Shandruk (retired)

Department of the Air Force
Cindy L. Elmore, Ph.D., DABR
LTC Scott Nemmers, BSC

Department of the Army
COL Mark W. Bower, CHP, Ph.D.
COL Erik H. Torring, DVM, MPH
Department of Labor,                  355
Occupational Safety and Health Administra36&
Doreen G. Hill, MPH, Ph.D.             357
Department of the Navy                359
CAPT Stephen T. Sears, MC, CO-CHAIR 360
CAPT Michael A. Ferguson, MC
CDR Douglas W. Fletcher, MSC
CDR Chad A. Mitchell, MSC

Department of Veterans Affairs
Ronald C. Hamdy, MD, FRCP, FACP
Edwin M. Leidholdt, Jr., Ph.D.
Eleonore D. Paunovich, DOS, MS
Environmental Protection Agency
Michael A. Boyd, MSPH

Commonwealth of Pennsylvania
John P. Winston

Expert Consultants/Other Contributor?,
Kimberly Applegate, MD, MS, FACR
Charles E. Chambers, MD, FACC FSCAI
Steven Don, MD
Marilyn Goske, MD
Fred A. Mettler, MD, MPH, FACR
Terrence J. O'Neil, MD, FACP
S. Jeff Shepard, MS
Dana M. Sullivan, RT(R)(M) , DVA

Environmental Protection Agency
Helen Burnett (retired)
Jessica Wieder

Department of Health and Human Services
J. Nadine Gracia, MD
Sandra Howard

                                        DRAFT PROPOSAL

371                                      INTRODUCTION
373    There are a few commonalities that are integrated throughout this document.
375     1.  This guidance was written without regard to specific models of equipment
376     2.  It is intended to be a practical and appropriately prescriptive tool.
377     3.  A balance was struck between being sufficiently specific and keeping the document generic
378        enough to remain current.
379     4.  Dose reduction has been offset by increased utilization (number and type of procedures)
380     5.  Dose reduction technology should be incorporated into the equipment.
381     6.  Dose reduction technology only works when it is used.
382     7.  Operators need initial and periodic refresher training, easy to use tools (e.g., checklists),
383        and motivation.
384     8.  Dose reduction strategies should be integrated into protocols, where possible.
385     9.  Improvements in imaging and equipment will continue.
387    The fundamental objective in performing an x-ray examination is to obtain the required
388    diagnostic information with only as much radiation dose as is required to achieve adequate image
389    quality.  Achievement of this objective requires: 1) assuring equipment is functioning properly
390    and calibrated, 2) assuring equipment is operated only by competent personnel, 3) appropriately
391    preparing the patient, and 4) selecting appropriate equipment and using appropriate protocols.
393    Even more so than when the original FGR 9 (EPA 1976) was published in 1976, imaging in 2012
394    plays a critical role in medical care within the United States. In the approximately thirty years
395    that have elapsed since the early 1980s, medical imaging has grown rapidly in utilization and
396    capability (NCRP 1989a; NCRP 2009). Computed tomography (CT) provided a new cross
397    sectional imaging method, initially for evaluating the contents of the skull and then for other
398    body cavities and organs, for assessing tissues and organs that previously required surgery for
399    evaluation. This resulted in fewer exploratory  surgical procedures and permitted more accurate,
400    non-invasive diagnoses. The number of CT procedures is growing at a rate greater than 10% per
401    year.
403    Smaller image detector elements increased the  spatial resolution of CT imaging. Other
404    technological improvements have included improved mechanical function, multi-row detector
405    CT scanners, more capable computer technology, and improved x-ray tubes.  As a result CT now
406    permits evaluation of physiologic characteristics as well as anatomy, and permits pediatric exams
407    previously limited by motion artifact. Indications for imaging have increased as have use of
408    multi-sequence studies that allow organs to be  evaluated during several phases of contrast
409    enhancement.
411    Improvements in fluoroscopy detector systems and improvements in techniques and equipment
412    (catheters, stents, embolic agents) facilitated an increase in the number and variety of image-
413    guided interventions. These procedures replaced many open surgical procedures and now
414    provide new therapy options for many diseases.
416    With the vast information available through imaging and the increased availability of CT and

                                        DRAFT PROPOSAL

417    fluoroscopy systems, there has been a marked increase in the contribution of radiation dose from
418    x-ray based medical studies to the overall radiation dose to the US population.  CT imaging
419    studies increased from 3 million in 1980 to 62 million in 2006, at which time, scans were
420    increasing at the rate of 10% per year (ACR 2007d; NCRP 2009). During this period, the
421    estimated effective dose from all x-ray-related medical procedures other than radiation therapy
422    increased from 0.39 to 2.23 millisievert per year (mSv/y) (39 to 223 millirem per year (mrem/y)),
423    or from 11% to 36% of the total US population dose. By 2006, the annual x-ray effective dose in
424    the U S. virtually equaled that from radon as well as the worldwide collective dose resulting
425    from the Chernobyl disaster (ACR 2007d; NCRP 2009).
427    Human epidemiological studies have demonstrated the potential of ionizing radiation to induce
428    cancer at an effective dose greater than 0.1 Sv. It is prudent to consider that lower doses might
429    also carry a risk. National and international organizations have classified ionizing radiation
430    (including x-rays) as a known human carcinogen (NTP 2011).  These groups include the
431    National Toxicology Program and the World Health Organization's International Agency for
432    Research on Cancer (IARC 2012).
434    Technological advances have improved diagnostic capabilities and image quality. Some of these
435    advances entail increases in patient dose. However, some have provided new and effective
436    methods for reduction of radiation exposure. Improvements in film and film-screen  technology
437    permitted reduction in the amount of radiation dose necessary to obtain standard images like the
438    chest radiograph. Improvement in image intensifiers and digital image receptors decreased the
439    amount of radiation necessary for fluoroscopic studies and the advent of pulsed fluoroscopy
440    permits even further reduction in the radiation required for a given imaging study. Simple
441    advances such as "last image hold" that cause the last image acquired to remain on the video
442    display screen after the fluoroscopy is stopped markedly reduce the dose of radiation involved in
443    these studies. Transition to improved systems also markedly reduced the radiation dose
444    necessary for mammography.  In CT, improvements in detector composition and function, dose
445    modulation based on the patient's size and body part examined, advanced reconstruction
446    algorithms, and prospective acquisition gating during the cardiac cycle have all provided
447    methods to significantly reduce the radiation dose from imaging studies.
449    Research has demonstrated that these dose-reduction techniques are not always employed or
450    used to best advantage in medical imaging, and medical education does not typically provide
451    focus on the effects of and protection from radiation exposure (ICRP 2000b). Seemingly simple
452    and obvious items, like altering the energy and amount of radiation used in imaging  children as
453    compared with adults, have not been adopted universally. Some units with pulsed fluoroscopy
454    capability have never been used in that mode.  This document is intended to assist the reader in
455    appreciating the need for understanding doses from procedures and maximizing the benefit-risk
456    ratio in the use of medical imaging systems.
458    The primary goal of medical imaging is to answer a clinical question or guide an intervention.
459    When performing medical imaging with ionizing radiation, using only as much radiation dose as
460    is required to achieve adequate image quality should be the second goal. There are several ways
461    to reduce radiation dose that will be discussed specifically in the sections dedicated to each
462    imaging  modality.

                                         DRAFT PROPOSAL

464    Important ways to reduce radiation exposure to patients are to avoid duplicate studies and to
465    avoid any study that does not contribute effectively to the primary goal of answering the clinical
466    question. Sharing digital images among facilities reduces patient radiation doses by precluding
467    unnecessary duplicative imaging.  The individual requesting the imaging examination should
468    have sufficient knowledge of the radiation doses associated with imaging examinations to be
469    able to request the most effective imaging study that provides the necessary information at the
470    lowest radiation dose. When appropriate, examinations not involving ionizing radiation are
471    preferable.  Organizations, such as the American College of Radiology (ACR) and American
472    College  of Cardiology (ACC), have published guidance that can help health professionals choose
473    the most appropriate examinations to answer their clinical questions.
475    As an example, in the evaluation of a patient with cough and fever, a standard two view chest x-
476    ray series may provide adequate information for the diagnosis and treatment of pneumonia at a
477    small fraction of the radiation dose that would be delivered by a chest CT. Similarly, a CT
478    angiogram may provide visualization of a large vascular distribution in a single imaging run with
479    a lower radiation  dose than the multiple digital subtraction angiographic sequences that may be
480    required to adequately visualize the same area.
482    Once a specific imaging study is selected, technical aspects of the image acquisition become the
483    most critical influence on radiation dose delivered to the patient and quality of the resulting
484    images.  Although reduction of radiation exposure overall should be a goal, reduction of dose to
485    a level that results in an increased number of unsatisfactory examinations requiring repeat
486    imaging will actually increase patient dose overall and should be avoided as much as excessive
487    dose should be. In the use of film-screen technology, over and under exposure were evident on
488    the resulting image, but with digital based imaging, these conditions are not as apparent.  One
489    reason is that image quality may continue improving with increasing dose, even beyond what is
490    needed or adequate.  As a result, good clinical practices include effective quality control
491    programs, optimized imaging protocols providing only the necessary sequences, adjustment of
492    technical factors and dose of radiation for patient size and age, and employment of the best
493    available dose reduction technologies existing in the equipment in use.
495    This document is intended to assist the reader in validating their efforts and maximizing the
496    benefitrisk ratio in requesting and performing medical diagnostic and interventional procedures
497    involving x-rays.  The document is divided into sections based on imaging modality.

                                        DRAFT PROPOSAL

505    The International Commission on Radiological Protection (ICRP) has formulated a set of three
506    fundamental principles for radiation protection (ICRP 2007a; ICRP 2007c). These principles are
507   justification., optimization of protection., and application of dose limits.  The first two principles
508    apply to a source of exposure, and thus are intended to support protection for all individuals who
509    may be exposed to that source. The third principle applies to occupational  and public exposure,
510    but explicitly excludes medical exposure of patients.
512    The principle of'justification states that, in general, "any decision that alters the radiation
513    exposure situation should do more good than harm. This means that by introducing a new
514    radiation source, by reducing existing exposure, or by reducing the risk of potential exposure,
515    one should achieve sufficient individual or societal benefit to offset the detriment it causes"
516    (ICRP 2007a; ICRP 2007c). With regard to medical exposures specifically, "the principal aim of
517    medical exposures is to do more good than harm to the patient, subsidiary account being taken of
518    the radiation detriment from the exposure of the radiological staff and of other individuals"
519    (ICRP2007a).
521    The ICRP (ICRP 2007a)  addresses justification in medicine as follows:
523           "The principle of justification applies at three levels in the use of radiation in medicine.
524           At the first level, the use of radiation in medicine is accepted as doing more good than
525           harm to the patient.  This level of justification can now be taken for granted.
527           "At the  second level, a specified procedure with a specified objective is defined and
528          justified (e.g., chest radiographs for patients showing relevant symptoms, or a group of
529           individuals at risk to a condition that can be detected and treated).  The aim of the second
530           level of justification is to judge whether the radiological procedure  will usually improve
531           the diagnosis or treatment or will provide necessary information about the exposed
532           individuals.
534           "At the third level, the application of the procedure to an individual patient should be
535          justified (i.e., the particular application should be judged to do more good than harm to
536           the individual patient). Hence all individual medical exposures should be justified in
537           advance, taking into account the specific objectives of the exposure and the
538           characteristics of the individual involved."
540    The principle of optimization of protection states that "the likelihood of incurring exposures, the
541    number of people exposed, and the magnitude of their individual doses should all be kept as low
542    as reasonably achievable, taking into account  economic and societal factors.  This means that the
543    level of protection should be the best under the prevailing circumstances, maximizing the margin
544    of benefit over harm" (ICRP 2007a; ICRP 2007c).

                                         DRAFT PROPOSAL

546    The principle ofapplication of dose limits states that "the total dose to any individual from
547    regulated sources in planned exposure situations other than medical exposure of patients should
548    not exceed the appropriate limits recommended by the Commission" (ICRP 2007a; ICRP
549    2007c).  It is important to note this definition explicitly excludes medical exposure of patients.
550    Dose limits do not apply to medical exposure, which is defined by the ICRP as "the exposure of
551    persons as part of their diagnosis or treatment (or exposure of a patient's embryo/fetus or breast -
552    feeding infant) and their comforters and carers (other than occupational)"  (ICRP 2007c).  As the
553    ICRP has stated, "Provided that the medical exposures of patients have been properly justified
554    and that the associated doses are commensurate with the medical purpose, it is not appropriate to
555    apply dose limits or dose constraints to the medical exposure of patients, because such limits or
556    constraints would often do more harm than good" (ICRP 2007c). This recommendation against
557    establishing absolute dose limits should not discourage a facility from implementing threshold
558    guidelines for diagnostic procedures that trigger a review of practice at the facility, or from
559    establishing dose notification and alert values for CT (NOTE:citeNEMA  standard XR25-2010 to
560    be provided by Ed 2012-08-17).
562    When an interventional procedure is indicated, the medical condition being treated and the non-
563    radiation risks of the procedure typically present a  substantially greater risk of morbidity and
564    mortality than do the radiation risks (Miller 2008).
566    While dose limits do not apply to medical exposures, each physician must always strive to
567    minimize patient irradiation to the dose that is necessary to perform the procedure. Therefore,
568    radiation doses to patients should always be optimized.
570    The concept of patient radiation dose optimization is used throughout this document.  Dose
571    optimization means delivering a radiation dose to the organs and tissues of clinical interest no
572    greater than that required for adequate imaging and minimizing dose to other structures (e.g., the
573    skin (FDA 1994)). Patient radiation dose is considered to be optimized when imaging is
574    performed with the least amount of radiation required to provide adequate image quality and, for
575    fluoroscopy, adequate imaging guidance (NIH NCI SIR 2005).  The goal of every imaging
576    procedure is to provide images adequate for the clinical purpose. What constitutes adequate
577    image quality depends on the modality being used  and the clinical question being asked.
578    Imaging requirements depend on the specific patient and the specific procedure.  Reducing
579    patient radiation dose to the point where images are inadequate is counterproductive; it results in
580    radiation dose to the patient without answering the clinical question, ultimately resulting in the
581    need for additional radiation dose.  Improving image quality beyond what is clinically needed
582    subjects the patient to additional radiation dose without additional clinical benefit. The goal of
583    patient radiation management is to keep patient radiation dose as low as reasonably achievable
584    consistent with the use of appropriate equipment and the imaging requirements for a specific
585    patient and a specific procedure.
587    Ideally, dose would be accurately measured or estimated in relevant tissues and organs in real
588    time. As of 2012, this is not possible.  Currently, radiation dose is measured differently for CT,
589    fluoroscopically-guided procedures, and radiography due to the endpoint health effect of interest
590    (cancer or acute tissue damage), the way radiation is  detected, and the way dose is calculated.
591    The dose metrics and units of measurement used for patient radiation dose measurement are

                                        DRAFT PROPOSAL

592    necessarily dependent on the equipment and modality being used.  Different dose metrics are
593    managed in different ways.  For example, during fluoroscopically-guided procedures, it is
594    desirable to optimize kerma area product and reference air kerma (indicators of patient dose)
595    while also minimizing peak skin dose.  The most appropriate dose metrics available should be
596    used.
601    Federal facilities must have safety programs in place to protect workers, as required by Public
602    Law 91-596, Section 19 entitled Federal Agency Safety Programs and Responsibilities (Congress
603    2004) and Executive Order  12196 entitled Occupational Safety and Health Programs for Federal
604    Employees (Carter 1980). For medical imaging the standards for protection against ionizing
605    radiation are promulgated by the Nuclear Regulatory Commission (NRC) for radioactive
606    materials in 10CFR20 (USNRC 2012c), and the US Occupational Safety and Health
607    Administration (OSHA) for x-rays in 29CFR1910 (OSHA 2012).  If both radioactive materials
608    and x-rays are utilized, then NRC regulations generally take precedence.  Portions of the NRC
609    and OSHA regulations, when considered together, establish dose limits for staff and members of
610    the public; requirements for the wearing of dosimeters; requirements for the posting of warning
611    signs; periodic employee training and hazard communication; comprehensive record keeping for
612    exposure monitoring results, periodic facility medical physicist assessments, and preventive
613    interventions;  and timely reporting of results of exposure monitoring and exposure incidents to
614    individual employees, including exposures to staffer members of the public that exceed
615    regulatory limits.  It is important to note that these dose limits are for occupational, incidental,
616    and public exposure and do not specifically limit the exposure that a patient may receive as a
617    result of medical evaluation or treatment in the process of their personal health care.  As of 2012,
618    and consistent with recommendations from ICRP, there is no regulatory limit on the amount of
619    radiation a patient may receive.
621          Minors as Workers
623    Readers of this document should be aware that the Federal Regulations cited above also provide
624    direction concerning occupational radiation exposure to individuals below the age of 18.  Dose
625    limits for these individuals are generally 10% of the occupational dose limits for adults.
627          Embryo or Fetus of Pregnant Workers
629    As of 2012, the occupationally received dose equivalent to the embryo or fetus of a radiation
630    worker who has voluntarily declared her pregnancy in writing shall not exceed 5 mSv (0.5 rem)
631    during the remainder of the pregnancy, or an additional 0.5 mSv (0.05 rem) if the gestation limit
632    has been or is within 0.5 mSv (0.05 rem) of being exceeded when the declaration is made
633    (USNRC 2012b). This limit does not pertain to the exposure of an embryo or fetus resulting
634    from a medical procedure to the pregnant worker.  When a radiation worker informally advises
635    the facility that she is, might be, or is attempting to become pregnant, her past and current
636    exposure values should be evaluated and risks associated with radiation exposure to the fetus
637    should be discussed.  If she formally declares her pregnancy (i.e., becomes a "declared pregnant

                                        DRAFT PROPOSAL

638    woman" per 1OCFR20.1003 (USNRC 2012a)), she should be issued a dosimeter to be worn on
639    the lower abdomen, under the apron, at the level of the fetus, and exchanged monthly, unless
640    such a dosimeter is already being worn.  The facility should avoid substantial variation above a
641    uniform monthly exposure rate of 0.5 mSv/month.
643          Members of the Public
645    The total effective dose equivalent to an individual member of the public should not exceed
646    1 mSv (100 mrem) in a year from occupancy in uncontrolled areas in or near medical radiation
647    facilities (NCRP 2004a).  In health care facilities, all non-radiation workers (e.g., janitorial staff,
648    secretaries) should be afforded protection consistent with that afforded members of the public.
649    This is relevant to the design of radiation shielding and occupancy limits.
654    There are several principles by which workers can minimize their exposure to x-rays. Most of
655    them are based on  certain fundamental concepts concerning x-rays: (1) limiting the time of
656    exposure reduces the dose, (2) except at short distances, radiation intensity is inversely
657    proportional to the square of the distance from the radiation source (Inverse Square Law), and (3)
658    x-rays travel in straight lines from their source and can be attenuated by shielding.  Those who
659    are exposed to radiation should judiciously use time, distance, and shielding to limit their
660    radiation dose.
662    Humans should be exposed to the unattenuated primary radiation beam(s) of x-ray imaging
663    equipment in federal medical facilities only for medical purposes. For this definition, "medical
664    purposes" include research involving the exposure of human subjects conducted in accordance
665    with the Federal Policy for the Protection of Human Subjects  (OSTP et al. 1991). In particular,
666    humans may not be exposed to these unattenuated beams solely for training, to test equipment, or
667    to obtain images for accreditation. The only exception to this requirement is that precision
668    assessments may be made in dual energy x-ray bone densitometry in accordance with the
669    guidelines  of the International Society for Clinical Densitometry (ISCD 2007a; ISCD 2007b).
671    Optimization of protection is at the heart of a successful radiation control program.  It involves
672    evaluating  and, where practical to do so, incorporating measures to reduce collective dose and
673    minimize the number of people exposed. In accordance with the ICRP' s principle of
674    optimization of protection, each facility  should use, to the extent practicable, procedures and
675    engineered controls to achieve occupational doses and doses to members of the public that are as
676    low as reasonably achievable (ALARA), with economic and social factors being taken into
677    account. The ALARA approach is applied after it has been determined that a proposed activity
678    will not exceed any mandatory dose limit.
680    The ALARA approach requires that only people whose presence is necessary are permitted in the
681    room while images are acquired.  For radiation protection purposes,  it is strongly recommended
682    that these people be shielded from radiation by means such as protective aprons and/or portable
683    shields and maintain as much distance as possible from the point where the x-ray beam intersects

                                         DRAFT PROPOSAL

684    the patient.  To limit worker dose, it is strongly encouraged that the operator be behind a shielded
685    barrier when observing the patient during image acquisition.
690    A radiation safety program is the mechanism for an institution to ensure that:
691        •  the use of ionizing radiation within its purview is performed in accordance with existing
692           laws and regulations,
693        •  individual health professionals and technologists are equipped with knowledge of the
694           options available to them as they make benefitrisk determinations and prescribe the
695           appropriate examination for each individual patient, and
696        •  x-ray equipment users and the surrounding public receive adequate protection from this
697           radiation.
698    The primary objective is to obtain necessary diagnostic information or interventional results with
699    minimum irradiation of the patient. This also helps keep exposure to staff and members of the
700    public at a minimum. The key personnel and activities involved in managing a radiation safety
701    program are:
703          Radiation Safety Officer
705    The Radiation Safety Officer (RSO) is responsible for radiation safety.  The RSO may be the
706    same person designated for radiation safety for NRC purposes under Title 10, Code of Federal
707    Regulations, Part 35 (USNRC 2012d). An RSO should be designated for each facility that uses
708    ionizing radiation for medical imaging, and should be appointed in writing by the facility
709    director or agency.  The RSO shall be permitted to directly communicate with facility executive
710    management. The RSO, whenever possible, should be a qualified  expert as defined in this
711    document. The RSO should be a person having knowledge and training in ionizing radiation
712    measurement and evaluation of safety techniques and the ability to advise regarding radiation
713    protection needs (for example, a person certified in diagnostic medical physics by  the American
714    Board of Radiology, or in health physics by the American Board of Health Physics, or those
715    having equivalent qualifications).  The RSO has the following specific responsibilities:
717     1.   Establish and implement radiation safety procedures and review them periodically to assure
718         their conformity with regulations and good radiation safety and medical physics practices.
719     2.   Instruct personnel in regulatory requirements and proper radiation protection practices
720         before they begin working with radiation and periodically thereafter to maintain and update
721         that knowledge.
722     3.   Conduct or supervise radiation surveys where indicated and keep records of such surveys
723         and tests, including summaries of corrective measures recommended and/or instituted.
724     4.   Assure that area monitoring and personnel monitoring devices are used as required and
725         records are kept of the results of such monitoring. This function requires reviewing the
726         monitoring reports promptly to ensure that public and personnel doses do not exceed
727         regulatory limits and are ALARA, making dosimetry records available to each worker at
728         any time, and periodically informing workers of their dose record. These records will be

                                         DRAFT PROPOSAL

729         kept in a suitable organized file (readily retrievable but not necessarily on site) for the life
730         of the facility or as legally required.
731     5.   Assure that any warning signals on imaging equipment and suites are regularly checked for
732         proper function and that required signs are properly posted.
733     6.   Monitor compliance with the requirements of regulations and the requirements specified in
734         the facility's standard operating procedures.
735     7.   In conjunction with a qualified physicist, promptly investigate each known or suspected
736         case of excessive or abnormal exposure, determine the causes, take steps to prevent its
737         recurrence, monitor such corrective actions, and make appropriate reports.
73 8     8.   Ensure that required notifications and reports in the case of personnel overexposures and
739         radiation medical events are submitted as required by regulations.
740     9.   Promptly notify facility executive management of significant safety hazards, significant
741         violations of regulations, exposures of staff or members of the public that exceed regulatory
742         requirements, and radiation medical events.
743     10. Review or have a qualified expert review, prior to construction or modification, plans for
744         rooms in which x-ray producing equipment is to be installed, including room layout,
745         shielding (AAPM 2006c; NCRP 2004a), and viewing and communications systems, and
746         verify that the shielding is installed according to plan and functions as designed before
747         clinical use of the equipment.
749           Qualified Physicist
751    The services of a qualified physicist are essential  for the optimal use of medical imaging.  The
752    following services should be performed by or under the supervision of a qualified physicist:
754     1.   Participate in evaluation and selection of equipment
755     2.   Conduct acceptance testing of new equipment
756     3.   Monitor imaging systems at least annually
757     4.   Evaluate, in conjunction with the RSO, unexpected radiation events
758     5.   Oversee the technical Q A program
759     6.   Investigate the root causes of image quality issues and identify appropriate solutions.
760     7.   Design or review and approve x-ray room radiation shielding
761     8.   Perform verification surveys of x-ray room shielding
762     9.   Periodically review existing imaging protocols
763     10. Assist with development and evaluation of new and revised imaging protocols
764     11. Perform patient-specific radiation dose calculations (e.g., fetal dose calculations)
765     12. Provide training on quality control and radiation safety
766     13. Ensure that instruments used to monitor x-ray imaging systems are appropriate for the task,
767         appropriately calibrated for the task (e.g., energy and dose rate measurements), and
768         maintained
769     14. Evaluate the radiation-related aspects of research  protocols
771           Personnel and Area Monitoring
773    Each worker who is expected to receive more than 10% of the applicable dose limit should be
774    required to wear one or more dosimeters. There shall be a procedure for regular issuance and

                                        DRAFT PROPOSAL

775    replacement of dosimeters for exposure evaluation, and records of the doses received shall be
776    retained as required by NRC in 10CFR20 (USNRC 2012c) and OSHA in 29CFR1910.1096
777    (OSHA 2012). When a protective apron is worn, one dosimeter should be worn at the collar
778    outside the apron.  A second dosimeter may be worn on the abdomen under the apron. The two
779    dosimeter method provides a more accurate method of assessing effective dose (NCRP 1995).
780    When multiple dosimeters are issued to an employee, each dosimeter should be labeled to
781    indicate the location on the body where it is to be worn. Facilities should ensure that workers
782    wear dosimeters as required, and in the designated locations; failure to do so can result in
783    incorrect dose assessments.  Periodic assessments and feedback to employees regarding their
784    exposures are particularly important. If there is a question, the facility can also post dosimeters
785    in public areas adjacent to rooms where x-rays are produced in order to quantify the amount of
786    radiation a person in those areas might receive.  Facilities/agencies should use methods for
787    estimating individual doses based on the goal of assigning accurate doses. Federal regulatory
788    agencies should adopt methods and procedures consistent with NCRP Report No. 122, which
789    provides recommended methods for determining effective dose (E) (NCRP 1995).

791           Patient Safety
793    As with all medical procedures, there are critical elements of patient safety that must be
794    observed. The first critical element is ensuring that the correct patient undergoes the specified
795    diagnostic test or interventional procedure, and that the examination is performed on the
796    appropriate body part. To that end, each facility should have in place a specified method  for
797    verification of patient identity prior to events such as administration of medication or surgical
798    procedures. These precautions should also be extended to diagnostic and interventional imaging.
799    If the medical procedure involves intervention or a specific side of the patient's anatomy, the
800    specific body part should be  confirmed prior to the procedure.  The precautions should be
801    commensurate with the risk from the examination or procedure, with greater precautions being
802    taken for procedures of greater risk.
804           Radiation Safety Procedures for Fluoroscopy
806    It is strongly  recommended that, other than for the patient being examined, only staff and
807    ancillary personnel required  for the procedure, or those in training, be in the room during the
808    fluoroscopic  examination (AAPM 1998; ACR 2008c). No body part of any staffer ancillary
809    personnel involved in a fluoroscopic examination should be in the primary beam. However, if
810    primary beam exposure is unavoidable, it should be minimized. It is essential that all personnel
811    in the room during fluoroscopic procedures be protected from  scatter radiation by either whole-
812    body shields  or protective aprons.  For procedures performed using microampere fluoroscopy
813    systems, a qualified physicist should determine if aprons are required.
815    Aprons should provide the desired protection at an acceptable  weight, because the apron weight
816    itself can pose a substantial ergonomic risk to its wearer.  Apron weight can be reduced by using
817    thinner lead or by replacing lead, completely or partially, with a combination of one or more
818    other materials that have the  same or better attenuation for the scattered radiation from
819    fluoroscopic  beams. Though 0.5 mm lead-equivalent aprons are considered the  standard  as of


                                         DRAFT PROPOSAL

820    2012, an apron with thinner lead equivalence may provide adequate protection.  Based on the
821    calculation of effective dose (E} from dual monitors, a 0.3 mm lead-equivalent apron will result
822    in a value of E that is only moderately higher (7 to 16 %) than a 0.5 mm lead-equivalent apron
823    (NCRP 1995).  The two-dosimeter method described above under PERSONNEL AND AREA
824    MONITORING may be preferable for monitoring personnel in the room during high dose
825    interventional procedures. Monthly dose monitoring can also be implemented to ensure that staff
826    members who use garments with < 0.5 mm lead equivalent thickness continue to maintain an
827    occupational dose below the required dose limits. With these precautions in place, it is quite
828    possible to provide adequate protection with a 0.3 5 mm or less lead equivalent thickness.
830    Thyroid and eyes should be protected if the potential exposure to the worker will exceed 25% of
831    the annual regulatory dose limits for those organs.  It is strongly recommended that lead
832    personnel protective  equipment (e.g.,  aprons, gloves, thyroid collars) be evaluated at least
833    annually for lead protection integrity using visual and manual inspection (Miller et al. 2010b;
834    NCRP 2010). If a defect in the attenuating material is suspected, radiographic or fluoroscopic
835    inspection may be performed as an alternative to immediately removing the item from service.
836    Protective aprons, gloves and thyroid shields should be hung or laid flat and never folded, and
837    manufacturer's instructions should be followed.  Consideration should be given to minimizing
838    the radiation exposure of inspectors by minimizing unnecessary fluoroscopy.
840           Special Patient Populations
842    Specific special populations addressed here include:
844     1.   Pregnant patients
845     2.   Pediatric patients
846     3.   Patients enrolled in a research protocol
848    Occupational radiation exposure to minors and to the fetus of a pregnant worker is discussed in
849    the section General Standards for Protection Against Radiation.
851                 Pregnant patients
853    Because of the  special risk that radiation exposure poses to the embryo or fetus, each facility
854    should establish and  implement procedures to determine, before conducting an examination or
855    procedure, whether a female patient of childbearing age may be pregnant.
857    Signs should be posted in suitable locations, such as patient reception  areas and procedure
858    rooms,  asking female patients to notify staff if they might be pregnant. Consideration should be
859    given to alternate tests or procedures, such as ultrasound, that would not expose the embryo or
860    fetus to ionizing radiation, or to modifying the examination or procedure to reduce the radiation
861    dose  to the embryo or fetus.
863    Evaluation of the benefit:risk ratio in relation to the radiation dose from medical imaging in a
864    pregnant woman is very complex.  In instances where a study using ionizing radiation is deemed
865    necessary, every effort should be made to avoid exposing the fetus to the direct radiation beam.


                                         DRAFT PROPOSAL

866    If a patient is pregnant, a radiologist, radiation oncologist, or other physician knowledgeable in
867    the risk from the radiation exposure should work with the patient in making the decision whether
868    to perform the examination or procedure.  There should be a discussion of the benefits and risks
869    with a pregnant patient prior to the imaging unless an emergent need for the imaging or her
870    condition precludes this.  If a previously unrecognized pregnancy is identified after a procedure,
871    the referring physician should be notified and the patient counseled as appropriate.
873    The precautions should be commensurate with the risk from the examination or procedure to be
874    performed, with greater precautions being taken for procedures imparting larger radiation doses
875    to the abdomen or pelvic region of the patient.  The physician might consider delaying the
876    procedure until after pregnancy so as to avoid exposing the embryo or fetus.  For procedures that
877    may impart a dose to this region, and especially for those exceeding 0.05 Gy (5 rad), the
878    anticipated dose and associated risks should be included as part of informed consent and a serum
879    pregnancy test should be obtained, unless a physician determines that the delay caused by
880    performing the test would harm the patient.  A confirmatory pregnancy test would not be
881    necessary if pregnancy can be excluded by documented surgical or medical history. Procedures
882    that may impart a dose to the embryo or fetus exceeding 0.05 Gy (5 rad) are prolonged
883    fluoroscopic procedures to the abdomen or pelvis and CT imaging involving two or more scans
884    of the abdomen or pelvis.
886    The dose to a fetus should be estimated. If the dose to the embryo or fetus could exceed 0.05 Gy
887    (5 rad), a formal dose assessment should be performed by a qualified physicist and provided with
888    consultation to the referring physician so that the patient can be advised accordingly.  Doses at or
889    above 0.1 Gy (10 rad) warrant discussions between the patient and her  physician of potentially
890    adverse fetal effects, and the fetal dose assessment should be included in the medical record.
892                 Pediatric patients
894    Children are more sensitive to radiation and also have greater expected remaining life spans than
895    adults.  As such, children represent a population at greater risk for subsequent development of
896    radiation induced cancer than adults.  This difference in the benefitrisk ratio should be
897    considered in the prescription of medical imaging requiring ionizing radiation.  Alternative
898    imaging modalities that do  not use ionizing radiation, such as ultrasound or MRI, should be
899    considered for imaging children.
901    Protocols for all ionizing radiation imaging should be "child-sized" or  optimized so that the dose
902    is appropriate for the size of the infant or child (FDA 2001; Strauss et al. 2010). For
903    radiography, fluoroscopy, and CT, this key principle  holds true.  For example, unlike abdominal
904    CT studies performed in adults, pediatric CT studies usually do not require multiple passes
905    through the child's body. This reduces the radiation  dose to the child without compromising
906    diagnosis.
908                 Patients enrolled in a research protocol
910    All research involving human subjects that is conducted, supported, or  otherwise subject to
911    regulation by any Federal department or agency must conform to the most current version of the


                                         DRAFT PROPOSAL

912    Federal Policy for the Protection of Human Subjects (FPPHS) (OSTP et al. 1991). This policy
913    requires approval of research protocols by a properly constituted institutional review board (IRB)
914    and obtaining informed consent from the patient.
916    Many protocols use radiation that is medically indicated (also referred to as  "standard-of-care ").
917    Medically-indicated radiation is used to diagnose or guide treatment as a non-research medical
918    procedure for clinical management of the research subject. The radiation dose from a medically-
919    indicated procedure done as part of a research study should not require additional justification,
920    review, and approval by an IRB. When the radiation exposure is described as indicated for
921    research (the radiation use does not meet the criteria of "medically indicated") it must be
922    reviewed and approved. IRBs have responsibility for oversight  of research involving human
923    subjects, but usually seek the advice of the institution's Radiation Safety Committee regarding
924    the radiation risk from any non-medically indicated radiation use that is a component of the
925    research.
927          Analysis of Risk from Radiation
929    An analysis of risk to the human research subjects, including that from radiation exposure, must
930    be performed prior to preparation of the information to be provided to the subjects to seek
931    informed consent and prior to review of the research study by the IRB.  The risks of both
932    deterministic and stochastic effects from the radiation exposure  should be considered.  For
933    consideration of the risk of deterministic effects, the maximal doses to individual organs and
934    tissues should be estimated, although dose rate and dose fractionation may also be considered.
936    The risk from stochastic effects, particularly cancer, should also be considered. Ideally, this risk
937    should be calculated from estimating doses to individual organs and tissues and using organ and
938    tissue specific risk coefficients that account for the age and gender of the subject.  The
939    International Commission on Radiation Units and Measurements (ICRU) provides useful
940    information for determining patient dose (ICRU 2005,  or most current version). However, for
941    many imaging procedures, this approach would consume considerable resources and requiring it
942    would discourage many research studies from being performed.
944    The ICRP developed the quantity effective dose (E) for radiation protection purposes to assess
945    the risk of detriment to workers from stochastic effects caused by occupational exposure to
946    ionizing radiation (Harrison and Streffer 2007; ICRP 1991a). This quantity was intended to be
947    applied to a population of working-age adults of both genders. Although effective dose was not
948    intended to be used for assessing risk from medical exposures, it is commonly used to convey the
949    potential risk from radiation exposure for subjects participating  in investigational protocols
950    (Martin 2007). For many imaging procedures, the effective dose can be estimated easily.
951    Furthermore, effective dose provides a single quantity from participating in a research study that
952    can be compared to other sources of radiation exposure (e.g., medical procedures and natural
953    background radiation). From the research subject's perspective, this comparison is simple and
954    expresses the risk in a meaningful way. The effective dose may be used for estimating risk from
955    stochastic effects to human research subjects, but should not  be  used without considering its
956    appropriateness in light of the characteristics of the study population, including their ages and
957    genders, the body parts being irradiated, and their expected life-spans. ICRP Publication 62


                                        DRAFT PROPOSAL

958    (ICRP 1991b) provides guidance on the use of effective dose in estimating risk to human
959    subjects.

961          Informed Consent for Research Involving Radiation
963    To enroll in any research study using human subjects, participants must be knowledgeable about
964    the risks, benefits, privacy considerations and other matters. They must participate voluntarily
965    and must provide written informed consent using an IRB-approved consent form.  Requirements
966    for human research in x-ray imaging facilities are addressed in the Federal Register (OSTP et al.
967    1991) and are specified in the current Code of Federal Regulations sections that apply to
968    individual facility operations (e.g., 32CFR219 for DoD, 45CFR46 for DHHS, 40CFR26 for
969    EPA, and 38CFR16 for VA). Appendix A contains sample informed consent templates for the
970    research use of radiation, adapted from those used by NIH in 2012 (Nffl 2008a; NIH 2008b;
971    NIH 2010).
973    These consent documents have been developed for use when patients are irradiated for research
974    purposes as opposed to being irradiated for clinical care.  These documents explain risk based on
975    effective dose.  The maximum level of radiation risk should be expected to be minimal, minor to
976    intermediate, or moderate when the respective societal benefit is minor, intermediate to
977    moderate, or substantial (ICRP 1991b). The specific values of numerical dose for each of these
978    ranges may vary according to the specific IRB and the specific research population. The sample
979    consent templates in Appendix A may be considered as a starting point for IRB consideration for
980    the general adult population. These consent templates should be modified as appropriate to meet
981    the particular requirements or needs of a given study.
983          Occupational Radiation Safety Training
985    Each facility should train staff who operate x-ray producing equipment or who are routinely
986    exposed to radiation by the equipment. Training should be provided initially prior to utilization
987    of the equipment and at least annually thereafter. The training should be commensurate with risk
988    to the staff and to the patient. It  should include the risks from exposure to ionizing radiation,
989    regulatory requirements, recommendations of this guidance document,  facility requirements,
990    proper operation of the equipment, methods for maintaining doses to staff within regulatory
991    limits and as low as reasonably achievable, and guidance for protecting the patient and embryo
992    or fetus.
994          Notification and Reporting Requirements
996    If radiation exposures to staff or  members of the public exceed regulatory limits, the facility  shall
997    make notifications and reports as required by the NRC or OSHA (OSHA 2012; USNRC 2012c).

                                         DRAFT PROPOSAL

1002    To prevent inadvertent patient injury or the need to repeat exposures of patients, it is strongly
1003    recommended that interlock switches that terminate x-ray production not be placed on doors to
1004    any diagnostic or interventional x-ray room (NCRP 2004a).
1006    For the structural shielding of rooms containing x-ray imaging or x-ray-producing devices, the
1007    shielding design goal should be 5 mGy in a year to any person in controlled areas. For
1008    uncontrolled areas, the shielding design goal should be a maximum of 1 mGy to any person in a
1009    year (0.02 mGy per week) (NCRP 2004a).  Shielding design for and acceptance testing  surveys
1010    of imaging rooms should be performed or reviewed by a qualified physicist using appropriate
1011    methodology such as is provided in NCRP reports. Whenever room modifications are performed
1012    or the assumed shielding parameters change (e.g., new equipment, increased workload,  or altered
1013    use of adjacent spaces), the suitability of the design should be reviewed by a qualified physicist.
1014    The shielding design calculations, as-built shielding plans, and the report on the acceptance
1015    testing of the structural  shielding should be kept for the duration of use of the room for x-ray
1016    imaging. The American Association of Physicists in Medicine guidance should be used as
1017    appropriate, for modalities not covered in NCRP reports.  At the time of this writing, this
1018    includes guidance for PET/CT shielding (AAPM 2006c).
1020    Mobile radiographic equipment is frequently used for bedside examinations. Effective radiation
1021    protection in these circumstances is normally provided through exposure time and distance
1022    (NCRP 1989b; NCRP 2000; NCRP 2004a). When mobile radiographic or fluoroscopic
1023    equipment is used in a fixed location, or frequently in the  same location, it is strongly
1024    recommended that a qualified expert evaluate the need for structural shielding (NCRP 2004a).
1025    When radiographic or fluoroscopic equipment is used in a temporary facility (e.g., field
1026    hospital), the effective use of distance, exposure time, or non-structural shielding may eliminate
1027    the need for structural shielding.
1032    The following section uses the terms Referring Medical Practitioner and Radiological Medical
1033    Practitioner. The Referring  Medical Practitioner is a health professional who, in accordance with
1034    state and federal requirements, may refer individuals to a Radiological Medical  Practitioner for
1035    medical exposure (IAEA 201 Ib).  The Radiological Medical Practitioner is a health professional,
1036    with education and specialist training in the medical uses of radiation, who is competent to
1037    independently perform or oversee procedures involving medical radiation exposure in a given
1038    specialty (IAEA 201 Ib).
1043    A medical procedure should only be performed on a patient if it is appropriately justified and
1044    optimized for that particular patient. In this context, "appropriateness" is generally defined in
1045    terms of benefit and risk. The RAND corporation has developed a definition of "appropriate"


                                          DRAFT PROPOSAL

1046    that is widely used: the expected health benefit (i.e., increased life expectancy, relief of pain,
1047    reduction in anxiety, improved functional capacity) exceeds the expected negative consequences
1048    (i.e., mortality, morbidity, anxiety of anticipating the procedure, pain produced by the procedure,
1049    misleading or false diagnoses, time lost from work) by a sufficiently wide margin that the
1050    procedure is worth doing (NHS 1993; Sistrom 2008). In other words, the anticipated clinical
1051    benefits should exceed all anticipated procedural risks, including radiation risk. This implies that
1052    radiation should be included in the benefitrisk evaluation for each patient both before and during
1053    any procedure.
1055    As with any medical procedure, the requesting or "ordering" provider (i.e., the Referring
1056    Medical Practitioner) should have adequate knowledge of the patient,  understand the nature of
1057    the proposed and alternative imaging procedures, and fully comprehend the medical diagnostic
1058    and treatment options available in order to be able to assess the benefitrisk ratios for the imaging
1059    procedures. These ratios balance the benefit of the diagnostic examination being requested
1060    against the stochastic and deterministic risks to the patient from radiation exposure during
1061    imaging, as well as the benefits and risks from alternative radiological and non-radiological
1062    procedures. The Referring Medical Practitioner (with privileges at the facility/within the
1063    healthcare network for the ordering of radiograph!c studies) should have determined that
1064    sufficient clinical history, symptoms, signs, or findings exist to necessitate the examination. All
1065    exposures to radiation should involve a benefitrisk analysis, in order to  ensure that the expected
1066    benefits of the examination  outweigh the potential risks, and that the most appropriate
1067    radiological or non-radiological procedure is selected on the basis of its  benefit:risk ratio.  In all
1068    cases, the use of radiation in diagnostic medical imaging should be justified and optimized.  This
1069    is the responsibility of all involved providers and technologists. Dose management begins when
1070    a patient is considered for a procedure involving ionizing radiation, involves equipment setup
1071    before the exam begins, and ends when any necessary radiation-related follow-up is completed.
1073    Physicians and licensed independent practitioners (Referring Medical  Practitioners) who have
1074    the legal authority and privileges to request diagnostic imaging studies involving ionizing
1075    radiation should have a basic understanding of radiation effects and protection methods. Also,
1076    they should have an appreciation for the radiation dose involved in a study and the potential
1077    effects of this dose over the lifetime of the patient to properly assess the benefit:risk ratio. The
1078    justification of medical exposure for an individual patient should be carried out by the Referring
1079    Medical Practitioner, in consultation with the Radiological Medical Practitioner when
1080    appropriate. Each health care  facility should establish a formal mechanism whereby Referring
1081    Medical Practitioners have sources of information available at the time of ordering regarding
1082    appropriate diagnostic imaging methods to answer the clinical question and to optimize ionizing
1083    radiation dose to the patient. These may include decision support software or appropriateness
1084    criteria. A mechanism for consultation with Radiological Medical Practitioners should also be
1085    made available.
1087    One of the most important methods for reducing radiation exposure is the elimination of
1088    clinically unproductive examinations. This continues to be a significant, but largely unrealized
1089    opportunity. Appropriate education of the requesting physician, utilization of existing current
1090    recommendations (such as the ACR Appropriateness Criteria (ACR 2012)) and consultation with
1091    a Radiological Medical Practitioner prior to generation of the examination request can all


                                          DRAFT PROPOSAL

1092    improve the probability that the most appropriate examination is performed relative to the
1093    clinical question. Automated algorithms integral to electronic ordering systems have the
1094    capability to alert the referring provider to more appropriate examinations, and can alert them to
1095    unnecessary repeat examinations.
1097    Follow-up examinations are commonly done so that significant changes in clinical information
1098    are obtained for making proper decisions on continuation or alteration of the management of the
1099    patient.  These examinations may result in unnecessary patient exposure if repeated before
1100    significant changes in patient status occur; therefore, it is recommended that they be done only at
1101    time intervals long enough to make proper decisions concerning continuation or alteration of
1102    treatment.
1104          Qualifications to Request X-ray Examinations
1106    Requests for imaging examinations involving the use of x-rays in Federal health care facilities
1107    should be made only by physicians or other Referring Medical Practitioners who are licensed in
1108    the United States or one of its territories or possessions and privileged within the  healthcare
1109    facility or network.  Properly trained individuals such as physician assistants and  persons in
1110    postgraduate medical training status do not have to meet the above requirements, but should be
1111    under the general supervision of a licensed physician who does.
1113    It is recognized that medical students, interns, residents, and some physician assistants may not
1114    have  developed medical judgment as to which test would be most efficacious.  Such lack of
1115    experience is remedied by work under conditions where there is sufficient expert supervision and
1116    radiology providers available for consultation who  can monitor the appropriateness of
1117    examinations based on the clinical history and can provide assistance.
1119    In addition to the privileges for which broad qualifications are needed, there are a number of
1120    specialties which require  only limited types of x-ray examinations. For example, Doctors of
1121    Dental Surgery or Dental Medicine may request appropriate examinations of the head, neck, and
1122    chest, although such requests are normally confined to the oral region.
1124    Variances to the above qualification requirements should occur only for emergency or life-
1125    threatening situations, such as natural disasters.  Also, non-peacetime operations in the field or
1126    aboard ship could require such variances.  Equipment designed for field use might need  to be
1127    operated by those personnel available to assist in the performance of necessary medical, dental,
1128    and veterinary services.
1133    Responsible use of medical, dental, and veterinary x-ray equipment involves restricting its
1134    operation to properly qualified and supervised individuals.  Such a policy should  be established
1135    for each x-ray facility by  the responsible authority upon the recommendations of medical, dental,
1136    and veterinary staff. Eligible radiological medical practitioners include those who are granted
1137    privileges for equipment use on the basis of the needs of patients served by the facility.  These


                                          DRAFT PROPOSAL

1138    are privileges to use radiation-emitting equipment and are separate from privileges to perform
1139    procedures. Such privileges might include, as part of their practice, the use of CT equipment by
1140    radiologists and cardiologists; the use of fluoroscopes by cardiologists, radiologists, urologists,
1141    and others; and the use of dental x-ray equipment by dentists. Before radiological medical
1142    practitioners are granted equipment use privileges, it is strongly recommended that they receive
1143    adequate training in equipment use and radiation protection.  However, specific protocols
1144    limiting equipment use privileges to specified types of radiological medical practitioners should
1145    be part of the written policy statement.
1147    After completion of an accredited educational program and certification by a state or voluntary
1148    credentialing organization,  radiologic technologists should be able to produce radiographic
1149    images with lower average  patient doses than incompletely-trained or non-credentialed
1150    operators. Non-credential ed operators may have little or no formal training in anatomy, patient
1151    positioning, or radiation protection practices. Inadequately trained operators are likely to
1152    irradiate patients and themselves unnecessarily (EPA 2000).  Personnel responsible for image
1153    acquisition should be trained in patient preparation and positioning, selection of technique
1154    factors and acquisition parameters, radiation protection measures,  routine equipment QC, digital
1155    image post-processing and  image processing.  They should also be able to reduce to a minimum
1156    the number of repeat examinations.  Performance of imaging examinations by incompletely
1157    trained personnel is not justified except for emergent circumstances.
1159    In order to achieve lower patient doses, the operator's manual should be readily available to the
1160    user, and equipment operation should be guided by the manufacturer's instructions, including
1161    any appropriate adjustments for optimizing dose and ensuring adequate image quality.

1163           Radiological Medical Practitioners
1165    A Radiological Medical Practitioner is a health professional, with  education and specialist
1166    training in the medical uses of radiation, who is competent to independently perform or oversee
1167    procedures involving medical exposure in a given specialty.  Within the Radiology department,
1168    this individual is typically a radiologist. Other  individuals who use ionizing radiation  for
1169    imaging, usually outside the Radiology department (e.g., cardiac catheterization or fluoroscopy
1170    in the operating room), are  also considered Radiological Medical Practitioners.  These
1171    individuals, when acting as a Radiological Medical Practitioner, have the same responsibilities
1172    for imaging protocols and for supervising equipment operation that would otherwise be assigned
1173    to a radiologist.  The Radiological Medical Practitioner is also responsible for optimizing the
1174    dose of ionizing radiation.
1176           Radiologists
1178    A radiologist is a licensed physician or osteopath  who is certified in Radiology or Diagnostic
1179    Radiology by the American Board of Radiology or the American Osteopathic Board of
1180    Radiology (AOBR), or has  completed a diagnostic radiology residency program approved by the
1181    Accreditation Council for Graduate Medical Education (ACGME) or the American Osteopathic
1182    Association (AOA). Within the Radiology department, the radiologist generally serves as the


                                         DRAFT PROPOSAL

1183    Radiological Medical Practitioner. In addition to interpreting imaging studies, radiologists set
1184    protocols for examinations involving x-ray systems and play a critical role in the performance of
1185    studies.  Imaging protocols should be devised for each imaging system and each imaging study.
1186    These protocols should provide adequate image and study quality while optimizing the radiation
1187    dose, particularly to radiosensitive tissues. Considerations include identifying the appropriate
1188    area of coverage, collimation, number of views to be acquired, and image quality needs (which
1189    dictates the required x-ray beam energy and intensity). For CT, this includes CT-specific
1190    technique factors, area of coverage, and the number of CT examination phases.  Radiologists are
1191    a source of knowledge on the advantages and disadvantages of different imaging modalities and
1192    should be consulted when that expertise is needed.
1194          Medical Radiologic Technologists
1196    Medical Radiologic Technologists (MRTs) and Registered Cardiovascular Invasive Specialists
1197    (RCIS) having appropriate radiation and other training are the personnel who operate the
1198    imaging equipment, deliver the radiation to the patients and capture the diagnostic images. As
1199    such, they are extremely important in the optimized use  of diagnostic imaging.  Operator
1200    competence is normally achieved by successful completion of a training program which provides
1201    both a didactic base and sufficient practical experience.  The training program should be
1202    accredited by a mechanism acceptable to  the appropriate credentialing organization, e.g., the
1203    American Registry of Radiologic Technologists or Cardiovascular Credentialing International
1204    (CCI).  Continuing competence and professional growth should be encouraged with specific
1205    opportunities to further the technologist's knowledge and skills through attendance at workshops
1206    or by other means of training.
1208    The radiologic technologist should be familiar with and  facile at utilizing the imaging systems
1209    and the techniques and technology available to them to reduce patient radiation dose while
1210    producing clinically adequate images.  As a critical part of the healthcare team,  they should be
1211    empowered to question techniques and requests when alternatives which would deliver lower
1212    doses are available.
1216    Screening programs using ionizing radiation should be justified, and the doses should be
1217    optimized for screening. It is important to keep requirements current with technological
1218    advances.  There are several reasons why individuals without known disease or symptoms may
1219    be referred for imaging examinations.  Some are specifically for administrative or occupational
1220    safety programs such as the annual postero-anterior chest radiograph acquired to evaluate for
1221    pneumoconiosis in coal, silica and asbestos workers.  Self-referral by patients for screening
1222    imaging to evaluate for disease in the absence of symptoms is an increasingly common
1223    occurrence whose appropriateness should be weighed and the individual counseled on the
1224    benefits and risks. If screening has been shown to have  a positive benefitrisk ratio, it is
1225    generally warranted.  As an example, in 2012, one accepted screening program  is mammography
1226    (ACR 2009b). Generally, neither screening nor elective x-ray examinations should be performed
1227    on pregnant women.


                                         DRAFT PROPOSAL

1229          Chest Radiography
1231    Screening for tuberculosis is no longer performed in the United States with chest radiography,
1232    although this technique may still be required during disaster relief and humanitarian operations
123 3    in other parts of the world.
1235    "Routine" radiographs without specific indications or symptoms should not be performed on
1236    admission to the hospital or while an inpatient.
1238    Standard postero-anterior chest radiographs are performed periodically to evaluate certain
1239    populations with high occupational risk for lung disease.  These populations include coal miners,
1240    asbestos workers, silica workers and a few other specific populations. There are typically
1241    specific requirements for these images; yet, as with all other images, it is important to optimize
1242    the radiation dose delivered to the individual.
1244          Mammography
1246    Breast cancer is a common and significant health risk in the United States. Because of the
1247    importance of early detection in control and survival, mammography is an important screening
1248    modality. This technique has improved considerably since the publication of Federal  Guidance
1249    Report 9 (EPA  1976), especially with respect to reducing radiation dose per examination.
1250    Women and their health care providers are encouraged to refer to the most current NCI
1251    recommendations when deciding upon breast cancer screening examinations.  Mammography
1252    facilities must comply with the Mammography Quality Standards Act (MQSA) regulations
1253    (FDA2012c).
1257    There are two types of self-referral. One is patient self-referral, where patients refer themselves
1258    for an imaging procedure without having a physician request (referral). The other is physician
1259    self-referral where physicians  see patients, decide to perform imaging procedures on those
1260    patients, and then refer the patients to themselves or their own medical practice for the
1261    procedure.
1263          Patients Requesting Imaging on Themselves without a Referral from a Licensed
1264          Independent Practitioner (Referring Medical Practitioner)
1266    With the increased capabilities of imaging systems and particularly with CT imaging, there has
1267    been an increased interest in and demand for use of this technology to screen for pre-clinical
1268    disease in the general population. Such screening programs should be subjected to rigorous
1269    scientific evaluation,  as has been done for mammography, to ensure that the risk posed to the
1270    population screened does not outweigh the benefits in detection of disease.
1272          Physician Self-Referral
1274    In this context,  self-referral examinations are examinations requested or ordered by the same


                                          DRAFT PROPOSAL

1275    physician who subsequently performs or interprets them.  They are frequently performed by
1276    equipment operators lacking adequate training and having supervision by health professionals
1277    with inadequate radiologic experience. Some examinations performed by non-radiologists may
1278    occur because of the convenience of having the x-ray unit and the patient in the same location,
1279    or, in the case of civilian contract services, need to justify the equipment purchased or
1280    maintenance costs.
1282    Unnecessary radiation exposure caused by self-referral practices that are not diagnostically
1283    relevant generally need not occur in Federal health care institutions where facilities staffed by
1284    radiologists are normally provided.  Exceptions could be small operational units,  such as ships,
1285    field units, or isolated stations where the normal workload does not justify a  staff radiologist.
1286    Thus, the conduct of self-referral x-ray examinations should be permitted only by a physician
1287    whose qualifications to supervise, perform, and interpret diagnostic radiologic procedures have
1288    been demonstrated to the appropriate authorities.
1290    It is recognized that limited self-referral type examinations are performed in  Federal medical
1291    centers in certain clinical specialties. The use of such self-referral x-ray examinations should,
1292    however, be limited to studies unique to and required by the specialty of the  physician
1293    performing them and be consistent with a peer review policy.
1295    Self-referral practices in federal facilities are expected to be immune to economic considerations
1296    for the referring physician. Self-referral practices in contract civilian facilities can lead to
1297    overutilization due to economic incentives for the referring physician and should be prohibited.
1298    Exception may be made in remote areas where no practicable alternative exists.
1302    Optimal medical care requires appropriate interaction between the Referring Medical Practitioner
1303    and the Radiological Medical Practitioner. The information technology system also plays an
1304    important role. Requests for x-ray examinations should be considered as medical consultations
1305    between the Referring Medical Practitioner and the Radiological Medical Practitioner. A request
1306    should state the diagnostic objective of the examination and should detail relevant medical
1307    history including results of previous diagnostic x-ray examinations and other relevant tests.
1309    Whenever possible the Radiological Medical Practitioner should review all examination requests
1310    requiring fluoroscopy, CT, or other complex or high-dose studies before the  examination is given
1311    and preferably before it is scheduled.  For this reason, it is important that a thorough and accurate
1312    patient history be included with each examination request. Based upon the clinical question,
1313    history, and relevant available previous studies, the Radiological Medical Practitioner should
1314    direct the examination using standard protocols, with any appropriate addition, substitution, or
1315    deletion of views or sequences. It is preferable that changes in the examination be done in
1316    consultation with the Referring Medical Practitioner.
1318    Effective communication of the findings is an essential component of imaging studies. Facilities
1319    are strongly encouraged to have policies on the communication of findings that are consistent
1320    with the guidelines of accrediting organizations and professional societies (ACR  2010).


                                          DRAFT PROPOSAL

1322    The provision of care by more than one medical facility may result in duplication of imaging
1323    studies.  To prevent this, and as technology permits, the Referring Medical Practitioner should
1324    review the patient's medical record to determine whether the proposed imaging study would
1325    duplicate a previous study.  This requires that the reports and images from all studies are
1326    accessible through the patient's Electronic Health Record (EHR) (Congress 2007).
1328    When referral from one facility to a second is anticipated, only the studies needed for proper
1329    referral should be performed in the first facility. Those imaging studies should be made
1330    available to the second medical facility concurrent with the transfer, either electronically or in
1331    hard copy format.

                                         DRAFT PROPOSAL

1335    Quality assurance refers to those steps that are taken to make sure that a facility consistently
1336    produces images that are adequate for the purpose with optimal patient exposure and minimal
1337    operator exposure. Quality assurance may be divided into two major categories: quality
1338    administration and quality control.
1340    Quality administration refers to the management aspect of a quality assurance program.  It
1341    includes those organizational steps taken to make sure that testing techniques are properly
1342    performed and that the results of tests are used to effectively maintain a consistently high level of
1343    image quality. An effective program includes assigning personnel to determine optimum testing
1344    frequency of the imaging  devices, evaluate test results, schedule corrective action, provide
1345    training, and perform ongoing evaluation and revision of the quality assurance program.
1347    Quality control comprises the procedures used for the routine physical testing of the primary
1348    components of the imaging chain from the x-ray source, through processing, to the viewing of
1349    images, as addressed in Table 1. Each facility, through its radiation quality control team (e.g.
1350    qualified physicist and biomedical maintenance personnel), needs to track maintenance and
1351    monitoring procedures.
1353    Each facility performing medical imaging with x-rays should establish  in writing and implement
1354    a technical quality assurance, quality administration, and quality control program that conforms
1355    to the most recent version of the "ACR Technical Standard for Diagnostic Medical Physics
1356    Performance Monitoring of Radiographic and Fluoroscopic Equipment" (ACR 2006b) and the
1357    "ACR Technical Standard for Diagnostic Medical Physics Performance Monitoring of Computed
1358    Tomography (CT) Equipment" (ACR 2007b).  The program should include all aspects of the
1359    imaging process from image acquisition through image display.  For film-screen imaging, it
1360    should include film and chemical expiration dates and storage requirements, monitoring of film
1361    processing, dark-room conditions, cleaning of intensifying screens, the cleaning and performance
1362    of view boxes, the ambient viewing conditions in rooms used for image interpretation, and image
1363    repeat analysis. For imaging with solid state image receptors such as computed radiography and
1364    direct radiography, it should include testing calibration of the CR plate readers and direct digital
1365    detectors, cleaning and inspection of CR plates, image repeat/reject analysis, calibration of
1366    detector exposure indices, monitoring of doses to the image receptors(exposure indices),
1367    uniformity of the sensitivity of the image receptor inventory, cleaning and monitoring of the
1368    luminance and calibration of video monitors used for initial image QC  and interpretation, and the
1369    ambient viewing conditions in rooms used for image interpretation. Monitors for interpretation
1370    of grayscale images should be calibrated to the DICOM Grayscale Standard Display Function
1371    (NEMA 2009). These quality assurance measures are addressed in the Radiography section
1372    under Testing and Quality Assurance.
1376    Technique factors should  be established for each imaging procedure. For radiographic
1377    examinations, these include kV, mAs and exposure time if automatic exposure control is not
1378    used, and perhaps choice  of image receptor. For CT examinations, these include kV, mA,


                                         DRAFT PROPOSAL
rotation speed, pitch, selection of a mode in which mA is modulated during the scan (if
available), and degree of noise reduction (if available). Technique factors may be programmed
into the imaging device, or they may be manually selected. If they are programmed in,
programming should be consistent across all similar devices at a facility. Technique factors
should be chosen that produce a clinically-adequate image at the least dose to the patient, not an
ideal image. Whenever possible, technique factors should be adjusted to the thickness of the

If the review of technique  factors used clinically or the comparison of dose indices indicates that
an optimum balance has not been achieved between patient dose and image quality or that
patient doses exceed national  standards, the technique factors, whether posted in a chart or
programmed into the imaging device, and/or selection of image receptor, should be modified as


It is strongly recommended that the technical quality assurance program includes testing by a
qualified physicist of all imaging equipment producing x-rays. The  equipment should be tested
after installation but before first clinical use, annually thereafter, and after each repair or
modification that may affect patient dose or image quality. Testing after repair or modification
should be performed before clinical use of the equipment. The testing, including a summary of
methods, instruments used, measurements and deficiencies identified, should be documented in a
written report signed by the qualified physicist. The testing  should include the items in Table 1

        Table 1. Testing Frequency of Imaging Equipment that Produces X-Rays
Measure radiation output parameters, including
beam intensity and beam quality
Test modes of operation used clinically, such as
automatic control systems (e.g., automatic
exposure controls of radiograph! c systems,
automatic exposure rate controls of fluoroscopy
Assess image quality
Determine Detector Exposure Index Accuracy
Evaluate the accuracy of patient dose or dose
rate indicators
Assess the typical patient dose delivered for
various examinations for comparison to national
reference levels
Perform an acceptance test


                                         DRAFT PROPOSAL
                Table 1. Testing Frequency of Imaging Equipment that Produces X-Rays
Review the overall technical quality control
Perform a periodic review of all CT protocols (c)


(a) Testing following repairs or modifications may be limited to features and parameters that
would be affected by the repairs or modification.
(b) Determine accuracy of detector exposure indices according to AAPM TGI 16 methodology
(AAPM 2009) and manufacturer's recommendations if available.
(c) The review of CT protocols should be performed together by the radiologist, CT technologist,
and medical physicist. Consider staggering annual reviews throughout the year to maintain
momentum without impacting schedules.
The qualified physicist may be assisted by other properly trained persons in obtaining test data
for performance monitoring. These persons should be trained by the qualified physicist in the
techniques for performing the tests, the function and limitations of the imaging equipment and
test instruments, the reasons for the tests, and the importance of the test results. The qualified
physicist should be present at the facility for the initial and annual testing and should promptly
review, interpret, and approve all data measurements and test results.


When x-ray imaging equipment fails to meet the performance specifications, the equipment
should be promptly adjusted or repaired to correct the deficiency or  should be removed from
clinical use.  A written or electronic record should be kept of the correction of such deficiencies
in accordance with the organization's record keeping policy.  The record should include the date
of correction and the action taken to correct the deficiency.


After correction of deficiencies that affect patient dose or image quality, the equipment should be
tested promptly, by or under the supervision of a qualified physicist, to verify that the deficiency
was corrected and that the correction did not cause other deficiencies.


Patient dose indices, measured at clinically-used technique factors by or under the supervision of
a qualified physicist, should be available for review. For radiography, entrance skin exposures
for common projections should be listed for a patient of typical thickness. For fluoroscopy
systems that have appropriate dosimetry measurement capabilities (e.g., air kerma or dose area
product), the accuracy should be measured and recorded. For fluoroscopy  systems that do not
have dosimetry indicators, the typical and maximal entrance skin exposure estimates should be
measured and recorded for each fluoroscopic mode of operation for  small, average, and large
patient thicknesses.

                                         DRAFT PROPOSAL

1438    The primary purpose of an imaging study using ionizing radiation is to answer a clinical question
1439    or assist in making a diagnosis. Production of such a study results in two determinants: the
1440    qualitative evaluation by the health professional of the clinical value of the study, and the amount
1441    of radiation exposure required to conduct it.  Each study should be evaluated for acceptable
1442    quality by a qualified individual (technologist or Radiological Medical Practitioner). A
1443    representative sampling and assessment of exposure indicators from each modality should be
1444    performed at least annually, but preferably quarterly, by a radiologic technologist under the
1445    guidance of a qualified physicist.
1447    Reference levels (RLs) are values used as quality assurance and quality improvement tools.
1448    Quality improvement uses quantitative and qualitative methods to improve the safety,
1449    effectiveness, and efficiency of health care delivery processes and systems.  Left unchanged, a
1450    system will produce the same results it has been achieving or degenerate.  To achieve a higher
1451    level of performance, the system must be changed.
1453    RLs were first introduced in the 1990s  (ICRP 2003; Wall and Shrimpton 1998). RLs are used to
1454    help avoid radiation dose to the patient that does not contribute to the medical imaging task
1455    (ICRP 2003).  They are intended to provide guidance on what is achievable with current good
1456    practice rather than optimum performance, and help  identify unusually high radiation doses  or
1457    exposure levels (ACR 2008b; IAEA 1996). RLs are a guide to good practice, but are neither
1458    dose limits nor thresholds that define competent performance of the operator or the equipment
1459    (Vafio and Gonzalez 2001). For assessments where the dose metric is determined using a
1460    phantom, a value above the reference level requires investigation. On the other hand, for
1461    interventional procedures, if the mean dose metric for a number of cases of a procedure exceeds
1462    the reference level, it does not always mean that the procedure has been performed improperly.
1463    Similarly, a mean dose metric for a procedure that is less than the reference level does not
1464    guarantee that the procedure is being performed optimally (Vafio and Gonzalez 2001).
1466    These levels are based on exposure to a standard phantom or actual patient dose metrics for
1467    specific procedures measured at a number of representative clinical facilities. RLs are set at
1468    approximately the 75th percentile (third quartile) of these measured data.  The use of RLs is
1469    supported by national and international advisory bodies (Amis et al. 2007; ICRP 2000a). These
1470    and other organizations have provided guidelines on measuring radiation dose  metrics and
1471    setting reference levels (IAEA  1996; ICRP 1991a; ICRP  1996; ICRP 2007c; Wall and Shrimpton
1472    1998). RLs can be specific to the country or region, and may be derived from multinational,
1473    national or local data (ICRP 2003; ICRP 2007b). As of 2012, U.S. reference levels are not
1474    available for most imaging studies. In  order to generate national RLs for the U.S., it is essential
1475    that institutions where these procedures are performed submit radiation dose metrics to a central
1476    dose registry.
1478    Each institution or individual practitioner should use reference levels as a quality improvement
1479    tool by collecting and assessing radiation dose data.  Standard phantoms are used where the
1480    procedure is standardized (e.g., chest radiograph or head CT). Patient dose metric data are
1481    collected if the procedure is individualized for each patient (such as fluoroscopically guided


                                         DRAFT PROPOSAL

1482    interventions) and should be collected for standardized procedures as well. The mean radiation
1483    dose for the examination is then compared to the reference level for that examination (ICRP
1484    2003).  If the mean radiation dose at the facility exceeds the reference level, equipment and
1485    clinical practices should be investigated in order to reduce radiation doses (NRPB 1990; Wall
1486    2001).  Equipment function should be investigated first, followed by review of the clinical
1487    protocol (Vano and Gonzalez 2001). Investigations are also appropriate where local values are
1488    substantially below the RLs, as excessively low doses may be associated with poor image quality
1489    (Baiter et al. 2008; IAEA 2009).  As appropriate, operator performance may be assessed if no
1490    other cause is found.  The development of reference levels requires consideration of the
1491    technique factors which most affect patient exposure. The Nationwide Evaluation of X-ray
1492    Trends (NEXT) is a program conducted by the Food and Drug Administration (FDA) in
1493    conjunction with the  States and the Conference of Radiation Control Program Directors
1494    (CRCPD) (FDA 201 Oa).  The NEXT data provide a profile of aspects of medical and dental
1495    imaging using ionizing radiation in the United  States at the time of survey. These data provide a
1496    window into clinical  practice because they reflect the myriad of combinations of imaging
1497    equipment, technique factors, and the skills of equipment operators.  Therefore, regardless of the
1498    specific details  of technique or combinations of all these factors, the frequency distributions of
1499    dose derived from the NEXT data were assumed to be sufficiently representative of the complex
1500    interaction of Referring Medical Practitioner preference, Radiological Medical Practitioner
1501    preference, operator technique, and x-ray equipment performance for each of the selected
1502    standard examinations. Thus, NEXT data, when available and current, serve as a useful source
1503    for the development of national reference lev els in the U.S. (ACR2008b).
1505    Professional organizations in the U.S.,  such as the American College of Radiology (ACR 2008b)
1506    and the American Association of Physicists in Medicine (Gray et al. 2005), support the use of
1507    third quartile values of particular dose indices.  It is important, however, to emphasize that with
1508    good technique, practicable levels of exposure  for most patients will be below these levels.
1510    The ICRP considers RLs  a useful tool to help optimize patient radiation dose in fluoroscopically
1511    guided interventional (FGI) procedures (ICRP 2007c).  As of 2012, some  studies have presented
1512    RLs for cardiovascular procedures (Baiter et al. 2008; D'Helft et al. 2009;  Neofotistou et al.
1513    2003; Peterzol et al. 2005) and a limited number of interventional radiology procedures (Aroua
1514    et al. 2007; Brambilla et al. 2004; Hart et al. 2009; Miller et al. 2009; Tsalafoutas et al. 2006;
1515    Vano et al. 2008a; Vano et al. 2009; Vano et al. 2008b; Verdun et al. 2005). Unfortunately, the
1516    observed distributions of patient doses for most types of FGI procedures are very wide, because
1517    the dose for each instance of a procedure is strongly dependent on individual clinical
1518    circumstances.  A potential approach is to include the ' complexity' of the procedure in the
1519    analysis (Baiter et al. 2008; IAEA 2009; ICRP  2007c). Since, as of 2012, complexity cannot be
1520    quantified (with the exception of some interventional cardiology procedures), this adjustment is
1521    not possible for FGI procedures (Baiter et al. 2008; IAEA2009). Because of the high individual
1522    variability  of patient  dose in cases of FGI procedures, the number of cases recommended in the
1523    literature as sufficient to provide adequate radiation dose data for a single facility varies from 10
1524    to >50 (Vano et al. 2008a; Wall and Shrimpton 1998).
1526    It is expected that U.S.  reference levels will decrease over time as outlier institutions improve
1527    their equipment and practices. In the United Kingdom, reference levels derived from data in  the

                                         DRAFT PROPOSAL

1528    2000 review were approximately 20% lower than those derived from data in the 1995 review and
1529    approximately half of those determined in the mid-1980s (Hart et al. 2009).
1531    For each type of examination there exists, within available technology, an optimal combination
1532    of imaging equipment and technique factors to produce adequate images at doses below the
1533    reference level. Hence, it is important to evaluate each system's performance to determine
1534    whether dose is optimized and to maintain this by establishing appropriate procedures and
1535    conducting periodic monitoring.
1542    Except in emergency situations, informed consent should be obtained from the patient or the
1543    patient's legal representative and appropriately documented prior to the initiation of any
1544    procedure that is likely to expose the patient, or fetus if the patient is pregnant, to significant
1545    risks and potential  complications. When obtaining informed consent for image-guided
1546    procedures using ionizing radiation that are known to be potentially high dose, an estimation of
1547    the anticipated risks from the radiation dose should be communicated to the patient as part of the
1548    overall discussion of risks (NCRP 2010). When a delay in treatment would jeopardize the health
1549    of a patient and informed consent cannot be obtained from the patient or the patient's legal
1550    representative, an exception to obtaining informed consent is made (ACR 2006a).
1552    Once the physician or dentist determines that the prescription of an x-ray examination is
1553    warranted for diagnostic purposes, other factors become important in limiting patient exposure.
1554    Optimization of patient dose may not be accomplished, even when well-designed equipment is
1555    used, unless appropriate quality assurance programs exist to keep it functioning properly and
1556    those who operate it are properly qualified to use the features of the equipment. These latter
1557    considerations are discussed in the chapter on Technical Quality Assurance in Medical Imaging
1558    with X-Rays. To ensure that x-ray equipment used is justifiably representative of present day
1559    technological advances, authorities should develop and periodically review a planned
1560    replacement schedule for all types of diagnostic x-ray equipment used in their programs.
1562    All x-ray equipment used for the imaging of humans for medical purposes should be maintained
1563    so that it conforms, throughout its useful lifetime, to applicable FDA regulations  (FDA 2012g).
1564    Furthermore, users should be aware of upgrades to software and hardware that enhance safety.
1565    These should be evaluated and  considered for implementation.
1567    The qualifications of x-ray imaging equipment operators should be defined by the responsible
1568    authority in a written protocol which details: 1) who may operate x-ray imaging equipment and
1569    the supervision required, 2) the education, training, and proficiency requirements for x-ray
1570    imaging equipment operators, and 3) requirements for continuing education and demonstration
1571    of proficiency.  This policy should be reviewed and revised as required.
1573    Prior to each examination requiring ionizing radiation, there should be a pre-procedure


                                         DRAFT PROPOSAL

1574    "verification" that patient identity, intended procedure and positioning, and equipment are
1575    correct. Also, the technologist should confirm that the patient, if female, is not pregnant and
1576    that, if contrast media is to be used, the patient is not allergic to it. Invasive procedures and CT
1577    examinations require both pre-procedure "verification" and "time-out" processes.  Those
1578    processes should be as specified by The Joint Commission for invasive procedures under the
1579    Universal Protocol (The Joint Commission 2012a; The Joint Commission 2012b).

                                          DRAFT PROPOSAL

1583    General radiography is a service usually provided by a Radiology Department, either in a central
1584    department or satellite facilities. Requests (orders) for general radiography services are
1585    performed based on protocols for standard views of each anatomic area, modified, if needed, to
1586    suit special requests or circumstances. Authorized variations to these protocols should be made
1587    for patient age and body habitus.  Each medical center should have a written policy for the safe
1588    use of radiograph!c equipment. This policy should apply to all radiographic equipment, whether
1589    fixed or portable. This policy should:
1591     1.  require testing of the radiographic equipment by a qualified physicist (or under their
1592        guidance for facilities or locations where it is not practicable to provide such staffing),
1593     2.  require training and credentialing of persons operating or directing the operation of
1594        radiographic equipment, and
1595     3.  specify procedures for the safe use of the equipment, including dose management and
1596        recordkeeping.
1598           Equipment
1600    Beginning in the 1990s, a transition occurred from film-screen radiography to digital
1601    radiography (radiography using other image receptors). These newer image receptor
1602    technologies include storage phosphor plates and several direct-image-capture technologies. All
1603    of these digital radiography technologies produce digital images that are most commonly viewed
1604    on video monitors, although the images may be printed on film using a laser printer, chemically
1605    developed, and examined on a view box.
1607    With film-screen radiography, there is feedback to the technologist if technique factors, primarily
1608    mAs, result in an excessive exposure to the patient.  The pertinent measure of the response to
1609    radiation exposure is the optical density of the film.  Optical density is a non-linear function of
1610    radiation exposure.  In film-screen radiography, when imaging a specific projection of a
1611    particular patient, only a narrow range of patient exposures will produce an adequate image. An
1612    exposure greater than this range produces an "overexposed" film with excessive optical density
1613    and inadequate image contrast, and an exposure below this range produces an "underexposed"
1614    film with excessively low optical densities and inadequate image contrast. Thus, provided that
1615    an appropriate x-ray tube voltage is used and the film is properly developed, the choice of film-
1616    screen combination largely determines the radiation exposure to a patient of a given size.
1618    There are advantages and disadvantages to digital image receptors in comparison to film-screen
1619    receptors.  Digital receptors respond to radiation over a wide range of exposures. The statistical
1620    noise in the image varies with the exposure, with higher exposures producing images with
1621    relatively less statistical noise. One of the many advantages is that the wide range of exposures
1622    permits the exposure for a particular image to be matched to the  clinical task - for an imaging
1623    procedure in which more statistical noise can be tolerated, a lower exposure can be used.
1624    Another advantage is that images acquired with overly high exposures and some of those
1625    acquired with overly low exposures may still be useful, avoiding retakes. An image acquired

                                         DRAFT PROPOSAL

1626    with an excessively low exposure will have excessive statistical noise, but this may not render
1627    the image uninterpretable.
1629    There are also disadvantages to digital radiography.  Digital image receptors facilitate acquiring
1630    multiple images, which may encourage the acquisition of more images than are clinically
1631    necessary. As of 2012, radiography with storage phosphor plates may require significantly
1632    larger patient exposures, by a factor of 1.5 to 2, than rare-earth phosphor film-screen systems to
1633    produce images of equivalent quality (Compagnone et al. 2006; Seibert et al. 1996). In digital
1634    radiography, an excessive exposure decreases statistical noise and will likely produce an image
1635    that is of higher quality than needed for the clinical task. Furthermore, it may not be apparent to
1636    either the technologist or the Radiological Medical Practitioner that the exposure was excessive.
1637    Thus, there may be a tendency for technologists to routinely use unnecessarily high exposures, a
1638    phenomenon called "dose creep" or "exposure creep" (Freedman et al. 1993; Seibert et al. 1996;
1639    Willis and Slovis 2005).  Excessive exposures are especially likely when using manually  selected
1640    technique factors instead of automatic exposure control.  Examinations made using storage
1641    phosphor plates and mobile radiographic machines are particularly susceptible to excessive
1642    exposures. Excessive exposures can also occur due to improper calibration of the automatic
1643    exposure control system, the incorrect configuration of protocols, or the use of an inappropriate
1644    protocol when automatic exposure control is used. Deliberate use of a protocol that provides an
1645    excessive exposure to avoid retakes or criticisms due to underexposure should be avoided.
1647          Testing and Quality Assurance
1649    Quality assurance measures for radiographic imaging using film-screen image receptors are well
1650    established, and are described in several publications (AAPM 2006b; ACR 2006b; NCRP
1651    1989b).  These measures include, among others, cleaning of image intensifying screens;
1652    establishing technique charts for exposures; and monitoring film processing, darkroom
1653    conditions, film storage, retakes, inadequate images, view boxes, and viewing conditions.
1654    Digital radiography retains some of the quality assurance issues seen with film screen image
1655    receptors, eliminates others, and adds new ones (AAPM 2005; AAPM 2006a; ICRP 2004).
1657    Storage phosphor image receptor systems and many direct image capture systems provide the
1658    capability to monitor the exposure to the image receptor from each individual imaging exposure,
1659    with a quantity termed the exposure indicator. The exposure indicator relates to receptor
1660    exposure, and not directly to patient dose.  As of 2012, each manufacturer of these systems
1661    defines,  calculates, and names their exposure indicator differently.  These proprietary exposure
1662    indicators are not consistent. Some are proportional to the exposure and others are proportional
1663    to the logarithm of the exposure.  Some increase as the exposure to the image receptor increases
1664    and others decrease as the exposure increases. A standard  indicator of exposure to the image
1665    receptor (called the Exposure Index) for adoption by all manufacturers was developed and
1666    published in 2009 and adopted by the International Electrotechnical Commission (AAPM 2009;
1667    IEC 2008).  Each facility should have a program for monitoring indices of exposure to image
1668    receptors, and work toward adopting the standard index when feasible after it is  adopted.
1669    Facilities should work with their Radiological Medical Practitioners and qualified physicists to
1670    develop procedures and establish target Exposure Index values and respective Deviation Index
1671    ranges by category of examination and patient population.


                                         DRAFT PROPOSAL

1673    Quality assurance measures should be adopted for digital radiography (ACR 2007a). Table 2
1674    below in the procedures section lists these measures.
1676    It is strongly recommended that radiographic technique factors be established for common
1677    procedures. These either should be programmed into the x-ray machine or a technique chart
1678    should be immediately available to the operator. Because of the phenomenon of dose creep, the
1679    use of appropriate technique factors is especially important in digital radiography.  The technique
1680    factors for imaging protocols should be optimized for the age and size of the patient, and for the
1681    imaging task.  Although a qualified physicist can assist with this process, protocol optimization
1682    also requires the efforts of a Radiological Medical Practitioner.  This process can benefit from
1683    the involvement of a technologist and the vendor, as well. It is particularly important to optimize
1684    the technique factors for radiographic imaging protocols performed on infants and children since
1685    the preset vendor protocols may result in unnecessary radiation dose.
1687    Pediatric imaging imposes additional concerns.  It is strongly recommended that particular
1688    attention be paid to dose optimization for pediatric patients.  For pediatric patients the operator
1689    should determine the need for an anti-scatter grid (if removable) and patient immobilization.
1690    Collimation should be adjusted appropriately and technique  charts should be used for those body
1691    parts that do not cover the sensor of the automatic  exposure control device.
1693          Personnel
1695    Each person who directs the operation or operates  radiographic equipment should be trained in
1696    the safe use of radiographic equipment, in order to ensure adequate image quality and optimize
1697    patient dose. Also see the section on PERFORMING AND  SUPERVISING STUDIES:
1700                 Radiological Medical Practitioner
1702    Radiographic equipment should be operated under the  general supervision of a physician. This
1703    individual fulfills the responsibilities of the Radiological Medical Practitioner. Depending on the
1704    study,  the responsible physician may be a radiologist, a surgeon, a cardiologist, a
1705    gastroenterologist, or another medical specialist. This  individual should be appropriately trained
1706    in the imaging modality, should be familiar with the principles of radiation protection, and
1707    should have a  sufficient understanding of the medical imaging modality's features to determine
1708    the appropriate protocol to evaluate the patient's clinical symptoms.
1710                 Technologist
1712    The technologist is responsible for using facility-approved imaging protocols and radiation
1713    protection measures. Technologists should be trained to produce adequate quality radiographic
1714    images and to assist in the quality assurance program.  They should also be able to optimize
1715    various technique factors of the x-ray equipment to produce  an adequate radiographic image at
1716    the lowest practicable patient dose and to use optimal procedures in working with patients and
1717    ancillary equipment to reduce to a minimum the number of repeat examinations. Some operators


                                         DRAFT PROPOSAL

1718    have little or no formal training in anatomy, patient positioning, or radiation protection practices.
1719    Performance of x-ray examinations by these inadequately trained individuals is not justified
1720    except for emergencies.

1722                 Other personnel
1724    Only personnel with specific, appropriate training should be permitted to operate x-ray
1725    equipment.  The use of x-ray equipment by other individuals is warranted only in an urgent or
1726    emergent situation when qualified personnel as specified above are not available to perform the
1727    examination in a timely fashion.
1729          Procedures
1731    It is strongly recommended that a radiologist provide general supervision in facilities performing
1732    radiography. Aboard certified radiologist is preferred.  Periodic review of the radiograph! c
1733    images should be performed as part of the routine quality assurance process.
1735    X-ray examinations should be performed in accordance with approved imaging protocols.  The
1736    technologist should not perform any examination which has not been requested by an authorized
1737    person.
1739    Collimation restricts the useful beam to the clinical area of interest.  Collimation to exclude body
1740    areas not being examined should be used to minimize unnecessary exposure. Masking portions
1741    of a digital image is not a substitute for collimation.
1743    If it does not interfere with the examination, contact or shadow shielding, using leaded aprons or
1744    other shields, should be employed to shield those parts of the patient that are particularly
1745    radiosensitive and are within the primary beam. Gonadal shielding should be used as
1746    appropriate. It is strongly recommended that breast shielding be used for scoliosis examinations
1747    on girls and young women. All shields should be placed between the x-ray source and the tissue
1748    to be shielded.  When shielding is used, an automatic exposure control sensor should be selected
1749    that is not within the shadow of the shield, or manual exposure control should be used.
1751    A written outline containing the minimum number of views to be obtained and the equipment to
1752    be used for each requested examination should be made available to each Radiological Medical
1753    Practitioner and equipment operator in every radiology facility. Beyond the specified minimum
1754    views, the examination should be individualized according to a patient's needs.
1756    The outline of procedures should indicate who may authorize deviations from the standard set of
1757    views for any examination. Every effort should be made to reduce to a minimum the number of
1758    standard views for any  examination. The necessity of additional views, such as comparison
1759    views, should be determined by the Radiological Medical Practitioner.
1761    A periodic review of all standard examination procedures should be performed to determine if
1762    the established routine is achieving the objectives and whether modifications are warranted.


                                         DRAFT PROPOSAL
Continuation of a standardized examination procedure should be predicated on satisfying the
following criteria:

 1.   the efficacy of the examination is sufficiently high to assure that the diagnosis could not
     have been made with less risk by other non-radiological means or a smaller number of
 2.   consideration of previous similar examinations performed with multiple views established
     that in a significant number of the cases all views were necessary for the diagnoses
     rendered, and
 3.   the yield or outcome of the examinations offsets the radiation exposure delivered.

A periodic review should be performed at least annually by experts designated by departmental
leadership, and with the input of referring physicians. These reviews should consider applicable
regulations as well as the consensus and advice of professional  societies concerning the efficacy
of radiologic examinations.

Other quality assurance measures are listed in Table 2 below. The specifics of these measures
may change  over time. The user should consult the relevant AAPM testing protocols.
                  Table 2. Quality Assurance Measures for Film and Digital Modalities
Physicist testing
Processor Monitoring
Darkroom Cleaning
Processor Preventive
Screen Cleaning
Repeat Analysis
Darkroom Fog
Film-Screen Contact Test
Review Local Radiation
Protection and Quality
Control Operating

See Table 1

See section on Technical Quality Assurance in Medical
Imaging with X-Rays.
Clean crossover racks and perform sensitometry test.
Check for dust, clutter, etc.
Perform deep cleaning and evaluate darkroom chemicals as
recommended by the manufacturer.
Clean all screens in inventory according to manufacturer' s
Track the repeat/reject rate and ensure it is less than or
equal to 7% (NCRP 1988). Trends indicating deterioration
in performance or increase in patient dose should be
Lightly expose a film (image a step wedge at 70 kVp, 5
mAs). In the darkroom with safelight on, cover half the
latent image with an opaque material for at least 2 minutes
then develop the film. A visible line between the two parts
of the image indicates a darkroom fog problem.
Follow film-screen contact test tool instructions.
Revise as needed.

                                DRAFT PROPOSAL
Computed Radiography
Physicist testing
Image Plate Erasure
Quality Control Phantom
Image Acquisition
Transmit Phantom Image
to Interpreting Medical
Treatment Facility (MTF)
Operator Console
Repeat Analysis
Dose Monitoring
Detector Exposure Index
Image Plate Inspection
and Cleaning
Review Local Radiation
Protection and Quality
Control Operating

See Table 1
Weekly, or
daily if
unsure of
At least

See section on Technical Quality Assurance in Medical
Imaging with X-Rays.
Perform primary erasure of each plate following
manufacturer' s instructions. This should be performed
before use if the status of the plate is unknown or fogging is
anticipated. Plates in storage do not require erasing until
used (AAPM 2006a).
Follow manufacturer's recommendations.
For Teleradiology Sites Only: After acquisition of QC
image, transmit to interpreting MTF for verification of
image quality.
View and evaluate QC pattern (AAPM 2005), clean
Track the repeat/reject rate and ensure it is less than or
equal to 7% (NCRP 1988). Trends indicating deterioration
in performance or increase in patient dose should be
Review patient dose indices according to manufacturer's
Review exposure indicators according to AAPM TGI 16
methodology (AAPM 2009) and compare with guidance
levels. One source for appropriate guidance levels may be
the manufacturer.
Follow manufacturer's recommendations for proper
cleaning technique using approved cleaning solution and
proper safety precautions.
Revise as needed.
Direct Digital
Physicist testing
Quality Control Phantom
Image Acquisition
Operator Console

See Table 1
At least

See section on Technical Quality Assurance in Medical
Imaging with X-Rays.
Follow manufacturer's recommendations.
View and evaluate QC pattern (AAPM 2005), clean

                                DRAFT PROPOSAL
Direct Digital
Transmit Phantom Image
to Interpreting MTF
Repeat Analysis
Dose Monitoring
Detector Exposure Index
Review Local Radiation
Protection and Quality
Control Operating


For Teleradiology Sites Only: After acquisition of QC
image, transmit to interpreting MTF for verification of
image quality.
Track and trend the repeat/reject rate and ensure it is less
than or equal to 7% (NCRP 1988).
Review patient dose indices according to manufacturer's
Review exposure indicators according to AAPM TGI 16
methodology (AAPM 2009) and compare with guidance
levels. One source for appropriate guidance levels may be
the manufacturer.
Revise as needed.
Interpretation and QC
Display Monitors
User task: Visual
assessment using QC test
Physicist, technologist
tasks: Display system
Physicist tasks: display
system calibration
Monitor cleaning

and as

AAPM TG-18 Online Report 3, table 8a or equivalent
(AAPM 2005)
AAPM TG-18 Online Report 3, table 8b or equivalent
(AAPM 2005)
AAPM TG-18 Online Report 3, table 8c, or equivalent
(AAPM 2005)
Clean monitors with cleaner approved by manufacturer
Other External
Printer quality control
Digitizer quality control


Follow manufacturer's recommendations
Follow manufacturer's recommendations

                                         DRAFT PROPOSAL

1790    Fluoroscopy may be employed by a variety of services in a medical facility to guide procedures,
1791    including imaging.  It can be performed with fixed, mobile or portable fluoroscopy systems.
1792    Some fluoroscopically guided procedures can deliver a large radiation dose to the patient, even
1793    when used properly. Prolonged procedures may result in injury, including non-healing ulcers,
1794    and other tissue injuries (FDA 1994). Because staff must remain with the patient in the
1795    procedure room during fluoroscopy, their potential occupational radiation dose is non-trivial.
1796    Each medical center should have a written policy for the safe use of fluoroscopic equipment.
1797    This policy should apply to all fluoroscopy equipment, whether fixed, mobile, or portable, e.g.,
1798    mobile C-arm systems and mini C-arm systems. This policy should
1800     1.  require testing of the fluoroscopic equipment by or under the direction of a qualified
iRfll        physicist,
         2.  require training and credentialing of persons operating or directing the operation of
            fluoroscopic equipment,
^ ~_ .     3.  specify procedures for the safe use of the equipment, including dose management and
1805        recordkeeping, and
1806     4.  require a clinical QA/QI program for fluoroscopy.
1808    Although the aggregate population effective dose is larger from the use of general purpose
1809    diagnostic equipment and CT, the highest organ doses (especially skin doses) to individuals,
1810    other than in radiation oncology, generally result from interventional fluoroscopic procedures.
1811    These procedures may require high exposure rates for long periods of time; thus, it is of utmost
1812    importance that Federal health care facilities give particular attention to fluoroscopic
1813    examinations. Even for simple and low-dose fluoroscopic examinations, proper training is
1814    required to perform the procedure with the optimal radiation dose. Therefore, x-ray equipment
1815    capability should not exceed the medical mission of the facilities, i.e., fluoroscopy should not be
1816    available in facilities where qualified medical personnel are not assigned. Equipment, physicians
1817    and staff should all meet current guidelines of the American College of Radiology Technical
1818    Standard for Management of the Use of Radiation in Fluoroscopic Procedures and its successors
1819    (ACR2008c).
1821    Equipment requirements and training requirements for operators differ depending on whether the
1822    procedures to be performed will be relatively low dose or potentially high dose.
1823    Fluoroscopically guided procedures should be classified as potentially high radiation dose if
1824    more than 5% of cases of that procedure result in an air kerma at the interventional reference
1825    point exceeding 3 Gy or a kerma-area product (KAP) exceeding 300 Gy-cm2. Low dose
1826    procedures are below these levels (NCRP 2010).
1828          Equipment
1830    If the medical mission requires fluoroscopy, only image-intensified units (with image intensifiers
1831    or flat panel detectors) should be used. As of mid-2006, all fluoroscopic equipment sold in the
1832    United States provides a final indication of air kerma (proportional to radiation dose) at a
1833    reference point at the completion of the  examination.  This simplifies the process of measuring

                                          DRAFT PROPOSAL

1834    and recording radiation dose in the medical record.
1836    Some operative procedures, both minimally invasive and open surgical, performed both inside
1837    and outside the operating room, (e.g., hip replacement, transsphenoidal hypophysectomy, some
1838    endoscopic procedures) may require fluoroscopic assistance. In general, these procedures tend to
1839    be relatively low-dose. For these procedures, to the fullest extent practicable, only equipment
1840    with features such as last-image-hold and reduced dose pulsed fluoroscopy, or equipment with
1841    similar dose-reducing features, should be used.  The advantage of this technology is that the
1842    radiation exposure can be reduced compared to continuous fluoroscopy, while adequate image
1843    quality is maintained.
1845    For procedures with a potential for high patient doses (this includes most interventional
1846    radiology,  interventional  cardiology, interventional neuroradiology and endovascular surgical
1847    procedures), additional requirements apply for both equipment and personnel (Hirshfeld et al.
1848    2004; Lipsitz et al. 2000; Miller et al. 2003a; Miller et al. 2003b; Padovani and Quai 2005;
1849    Suzuki et al. 2006). Fluoroscopy equipment intended for these procedures should, at a
1850    minimum,  be compliant with the version of International Electrotechnical Commission Standard
1851    60601-2-43 (IEC 2010) applicable to the equipment at the time of purchase.  New fluoroscopic
1852    imaging systems should incorporate high heat-loading tubes, adjustable-rate pulsed fluoroscopy
1853    capability,  spectral shaping filters, and automatic exposure control logic to optimize radiation
1854    dose and ensure adequate image quality throughout the procedure. As future systems incorporate
1855    improved methods for both tracking and optimization of patient dose during fluoroscopically-
1856    guided procedures, purchasers and operators should take advantage of them when appropriate.
1857    The additional cost of dose-reduction technology is justified because the reduction in patient
1858    radiation dose can be considerable.
1860    Proper patient management during fluoroscopically-guided interventions requires appropriate use
1861    of the various features of the fluoroscopic equipment. This will permit patient dose to be
1862    optimized and staff dose to be minimized.  There is an extensive literature on this subj ect which
1863    can be used for guidance  (Chambers et al. 2011; Miller et al. 2010a; NCRP 2010; Stecker et al.
1864    2009; Steele etal. 2012).
1866    Measurement or estimation of skin dose is desirable for all procedures which are high dose or
1867    have the potential to result in high patient  dose.  The quantity of interest is the peak skin dose
1868    (PSD), the highest dose at any point on the patient's skin.  This determines the severity of a
1869    radiation-induced skin injury. Ideally, equipment should also provide the operator with a near
1870    real-time indication of skin dose, including PSD in the current radiation field. The operator
1871    would then be able to modify his/her technique during the procedure to minimize skin dose
1872    (FDA 1994; Miller et al. 2002). Skin dose can be measured with special films, an array of
1873    thermoluminescent dosimeters (TLDs), optically stimulated luminescence (OSL) dosimeters or
1874    real-time point-measurement devices (Baiter et al. 2002).  Currently, these methods are
1875    expensive,  cumbersome and inconvenient, and are not commonly used in routine clinical
1876    practice. In the future, software-based systems should be able to estimate and map skin dose in
1877    real time.
1879    Cumulative air kerma (cumulative air kerma at the reference point; also called reference point


                                         DRAFT PROPOSAL

1880    dose, reference air kerma, reference point air kerma, or cumulative dose) is measured in Gy and
1881    displayed automatically on all fluoroscopic equipment in the United States sold after mid-2006
1882    per 21CFR1020.32(k) (FDA 2012d). It is the dose at a pre-defined reference point. This point is
1883    separately defined for different types of fluoroscopic equipment (FDA2012d; FDA2012f).  For
1884    C-arm units, this point is located along the central ray of the x-ray beam, 15 cm from the
1885    isocenter towards the x-ray source (TEC 2010). Cumulative air kerma is not the same as skin
1886    dose. Cumulative air kerma is measured at a point in space that is fixed with respect to the
1887    gantry and can move with respect to the patient when the table is moved or the gantry is angled.
1888    Cumulative air kerma does not take table height or these motions into account. As a result,
1889    reference  dose is usually greater than PSD (IEC 2010; Miller et al. 2003a;  Miller et al. 2012).
1891    Kerma-area product (KAP, also called dose-area product or DAP) is the product of the air kerma
1892    and the area of the irradiated field and is measured in Gycm2.  It does not  change with distance
1893    from the x-ray tube. It is a good measure of the total energy delivered to the patient, and
1894    therefore a good measure of stochastic risk. It is not a good indicator of deterministic risk
1895    (Kwon et  al. 2011; Miller et al. 2012).
1897    Fluoroscopy time has been the standard dose metric. It is easy to measure and the capability to
1898    measure it is widely available. However, fluoroscopy time does not reflect the effects of
1899    fluoroscopic dose rate or the radiation dose from fluorography (e.g., digital subtraction
1900    angiography or cinefluorography) and is a poor indicator of patient dose. As recommended in a
1901    joint Society of Interventional Radiology/Cardiovascular and Interventional Radiological Society
1902    of Europe (SIR/CIRSE) guideline, use of fluoroscopy time as the sole dose metric is not
1903    advisable, and should not be done unless no other dose metric is available  (Stecker et al. 2009).
1904    Even then, the number of images and cine frames should also be recorded.  Procedures with a
1905    potential for high patient doses should not be performed using fluoroscopy equipment that is not
1906    compliant with IEC 60601 -2-43 or its successors (IEC 2010).
1908    For patient care and for quality assurance purposes, it is highly desirable for all radiation data to
1909    be transferred  automatically to the PACS (picture archiving and communication system), RIS
1910    (radiology information system), and Electronic Health Record (EHR) as part of the study data
1911    (along with images and demographic information) if the fluoroscopy unit is connected to a
1912    PACS.  These data should include the peak skin dose, if available; the cumulative air kerma from
1913    both fluoroscopy and from image acquisition, if available; the kerma-area  product, if available;
1914    and the cumulative fluoroscopy time and number of images or cine frames recorded (Miller et al.
1915    2012; NCRP 2010). The IHE REM integration profile provides a standard for the transfer of
1916    such information to the PACS ((ME 2008) or current version).
1918    There are  several relatively new technologies as of 2012 (e.g., cone-beam  CT,  surgical O-arms,)
1919    (ACR 2008c; Orth et al. 2008; Wallace et al. 2008).  Others will certainly  appear in future
1920    interventional  fluoroscopy equipment.  Some of these technologies are intended to provide
1921    greater technical capability for complex surgical or interventional procedures.  Currently, most of
1922    these technologies are designed to enhance the fluoroscopy unit's surgical  capability for
1923    procedures performed outside the Radiology Department.  Mobile equipment with these
1924    technologies is smaller in size than its conventional fixed counterpart, but  it can be just as
1925    dangerous to the operator and patient. Facilities should  establish procedures for the testing and


                                          DRAFT PROPOSAL

1926    use of these types of equipment, and for the training and credentialing of its operators.
1928           Testing and Quality Assurance
1930    Equipment testing for quality assurance should be performed by or under the direction of a
1931    Qualified Physicist after installation but before first clinical use, annually thereafter, and after
1932    each repair or modification that may affect patient dose or image quality. Testing should be
1933    performed as specified in the section of this document entitled Technical Quality Assurance in
1934    Medical Imaging with X-Rays.
1936           Personnel
1938    Fluoroscopy can deliver a significant radiation dose to the patient, even when used properly.
1939    Also, fluoroscopy presents the potential for greater radiation dose to the operator as compared
1940    with other imaging modalities.  Therefore, all fluoroscopic examinations should be performed by
1941    or under the direct supervision of a physician with demonstrated competence, who has received
1942    training in fluoroscopy and has been privileged by the facility to perform fluoroscopy.
1944    In fluoroscopy, the operator effectively determines, prescribes and delivers the required x-ray
1945    dose to the patient in real-time. These systems are often used to guide imaging or interventions
1946    and the exposure is directly related to the complexity of the procedure and inversely related to
1947    the skill of the individual performing the procedure. Individuals who are privileged for the use
1948    of these systems, and particularly the high dose capable systems as are used in interventional
1949    procedures should have a thorough understanding of the biological effects of radiation exposure,
1950    the dose from this radiation exposure and its likely deterministic and stochastic risks, and of the
1951    available technique and technology based methods for minimizing the radiation dose to any
1952    portion of the patient's tissue during the examination.
1954    Every person who operates or directs the operation of fluoroscopic equipment should be trained
1955    in the safe use of fluoroscopic equipment, in order to optimize patient dose. Initial training
1956    should include didactic training, hands-on training, and clinical operation under a preceptor.
1958    Didactic training is a formal course of instruction in radiation  safety which meets guidelines
1959    established by the responsible authority. It should include the  following topics: (a) physics of x-
1960    ray production and interaction; (b) the technology of fluoroscopy machines, including modes of
1961    operation; (c)  characteristics of image  quality and technical factors affecting image quality in
1962    fluoroscopy; (d) dosimetric quantities, units, and their use in radiation management; (e) the
1963    biological effects of radiation; (f) principles of radiation protection in fluoroscopy, (g) applicable
1964    federal  regulations and agency requirements; and (h) techniques for minimizing dose to the
1965    patient  and staff.  Completion of this phase of training should include successfully completing a
1966    written examination. Radiologists may fulfill the didactic portion of the initial training through
1967    the extensive training in radiation physics, radiation biology and radiation safety they receive
1968    during their residency.
1970    Hands-on training is conducted by a qualified individual who is familiar with the equipment.
1971    Hands-on training means operation of the actual fluoroscope that is to be used clinically (or an


                                          DRAFT PROPOSAL

1972    essentially similar fluoroscope), including the use of controls, activation of various modes of
1973    operation, and displays.  This phase of training could include demonstrations of the effect of
1974    different modes of operation on the dose rate to a simulated patient and could include
1975    demonstration of the dose-rates at various locations in the vicinity of the fluoroscope.
1977    Clinical operation under a preceptor means operation of the fluoroscope for clinical purposes
1978    under the direct supervision of a preceptor experienced in the operation of the device.
1979    Completion of this phase of training  should include written attestation, signed by the preceptor,
1980    that the individual has achieved a level of competency sufficient to function independently as a
1981    fluoroscopy operator.
1983    Training should be conducted initially and then at periodic intervals. Records should be kept of
1984    the training.  The records should include the date(s) of training, the name(s) of the person(s)
1985    providing the training, the topics included in the training, the duration of the training, the test
1986    questions, the names of the persons successfully completing the training, and the test scores of
1987    these persons.  The training records should also include the signed preceptor statements
1988    described above. Training need not be performed at or by the medical facility, provided that the
1989    facility determines that it meets these requirements and was sufficiently recent, and the facility
1990    obtains written certification of  successful completion of the training. Periodic refresher training
1991    should include the didactic training.  At the facility's discretion, it may also include hands-on-
1992    operation and clinical operation under a preceptor physician.
1994    Each person who operates or directs the operation of fluoroscopic equipment should be
1995    privileged by the medical facility.  Privileging should be contingent upon successful completion
1996    of training as described above.  Maintenance of privileges should be contingent upon successful
1997    completion of periodic refresher training and on complying with agency and facility
1998    requirements for the safe use of fluoroscopic equipment. In particular, it is not permissible for a
1999    physician or other medical professional  who has not completed this training, and who is not
2000    privileged, to direct the operation of a fluoroscopy unit even if it is operated by a radiologic
2001    technologist.
2003    Operators who perform fluoroscopically-guided procedures with the potential for high patient
2004    doses require additional knowledge and training beyond that necessary for operators whose
2005    practice is limited to low-dose fluoroscopy procedures (ICRP 2000a; Vano 2003).  Operator
2006    knowledge includes all the information described in the current American College of Cardiology
2007    Foundation/ American Heart Association/ Heart Rhythm Society/ Society for Cardiac
2008    Angiography and Intervention fluoroscopy clinical competence statement and its successors .  In
2009    general, radiologists and interventional cardiologists receive most or all of this information as
2010    part of their training, and are tested on this knowledge as part of the board certification processes
2011    by their respective Boards. Physicians in other medical specialties may or may not have received
2012    training or been examined on this subject matter during their residency or fellowship, and may
2013    require additional training.

                                          DRAFT PROPOSAL

2017          Procedures
2019    Fluoroscopic procedures should be performed so that procedure dose is optimized and skin dose
2020    is minimized.  This requires the appropriate use of various features of the fluoroscopic
2021    equipment.  Further details are available in the published literature (Miller et al. 2010b; NCRP
2022    2010; Sidhu et al. 2009; Stecker et al. 2009; Wagner et al. 2000).
2024                 Dose measurement
2026    Methods for estimating PSD can be ranked from most reliable to least reliable.  As of 2012, peak
2027    skin dose measuring software is the most reliable, followed by measurement of cumulative air
2028    kerma, KAP, and finally fluoroscopy time combined with a count of the number of fluorography
2029    frames or images.  Dosimeters placed on the skin are useful but can provide underestimates for
2030    PSD if placed outside the area of highest skin dose. This area may be quite  small  (Miller et al.
2031    2003a).  PSD and KAP are now the most useful predictors for deterministic and stochastic
2032    injury, respectively. Cumulative air kerma is readily available on fluoroscopy units purchased
2033    after mid-2006 and is  an acceptable substitute for PSD.  It does not correlate well with PSD in
2034    individual cases (Miller et al. 2003a; Miller et al. 2003b).  Fluoroscopy time alone does not
2035    correlate with PSD (Fletcher et al. 2002).  Monitoring fluoroscopy time alone also
2036    underestimates the risk of radiation-induced skin effects (O'Dea et al. 1999).
2038    All statements of patient dose contain some degree of uncertainty.  As of 2012, dose
2039    measurement accuracy in clinical units has an allowed calibration accuracy of ±35% (FDA
2040    2012d).  Even the most sophisticated dose-measurement instrumentation has unavoidable
2041    uncertainties related to variations in instrument response with changes in beam energy, dose rate,
2042    and collimator size. Converting these measurements into skin dose introduces yet further
2043    uncertainties related to beam orientation and inconsistencies in the relationship between the
2044    patient's skin and the  interventional reference point. Finally, clinically available dose and KAP
2045    measurements ignore  the effect of backscatter from the patient.  Backscatter causes the skin dose
2046    to exceed air kerma at the same location by 10 to 40%, depending on the beam area and energy
2047    (ICRU 2005, or most  current version). Skin doses estimated from reference dose, KAP, or
2048    fluoroscopy time may differ from actual skin dose by a factor of two or more.  Users of dose data
2049    should be aware of these uncertainties. Federal  facilities should strongly encourage the purchase
2050    of equipment with features that enhance the accuracy and clinical value of dosimetry  systems.
2052                 Recordkeeping
2054    A record should be kept of each fluoroscopic procedure. Whenever possible, this should be
2055    performed electronically, with automatic transfer of the necessary data, as appropriate, from the
2056    fluoroscopy unit to a PACS, RIS, and EMR (see above, under Equipment).  The record should
2057    list the individual fluoroscopy unit, the date of the procedure, the procedure (e.g., barium enema,
2058    iliac artery angioplasty and stent placement), information identifying the patient, and the name of
2059    the physician operating or directing the operation of the device. The record should also list the
2060    cumulative  air kerma  from both fluoroscopy and from image acquisition, if available; the kerma -
2061    area product, if available; the cumulative fluoroscopy time and number of images recorded; and
2062    other dose metrics as they are developed.  This record should be maintained according to the


                                          DRAFT PROPOSAL

2063    Federal facility's requirements.
2065    It is strongly recommended that patient radiation dose data be recorded in the patient's medical
2066    record, including patient skin dose data whenever possible.  Where and how these data are
2067    recorded is subject to the policies and procedures of the individual institution. However, the
2068    choice of dose metrics to be recorded should be guided by published recommendations,  such as
2069    the guidelines on recording dose in the medical record published by SIR (Miller et al. 2012;
2070    Miller et al. 2004; Stecker et al. 2009).
2072    When the dose to one or more areas of a patient's skin may have exceeded a threshold dose for
2073    deterministic effects, the physician performing the procedure should be advised of this event and
2074    should place an appropriate notation in the patient's medical record (Stecker et al. 2009). The
2075    information should include information on the beam entry sites and the estimated skin dose for
2076    each, if available. Provisions should be made for clinical follow-up of those areas for monitoring
2077    radiation effects.  The possibility of overlap of two separate adjacent fluoroscopic fields, where
2078    skin dose of the overlapping area may have exceeded the threshold dose, should be taken into
2079    account. Ideally, skin dose from radiation therapy and imaging modalities other than
2080    fluoroscopy should also be considered. It is recognized that at the time this report was prepared,
2081    no simple method for measuring or estimating skin dose is available. As a substitute, cumulative
2082    air kerma may be used.  Threshold values recommended by professional societies or advisory
2083    bodies, such as the ACR, SIR, ICRP and NCRP, should be consulted (ACR 2008c; ICRP 2000a;
2084    Stecker et al. 2009).  As of 2012, these threshold values are typically a PSD of 3 Gy or
2085    cumulative air kerma of 3 - 5 Gy (ACR 2008c; NCRP 2010).
2087                 Patient management
2089    Management of patients who have received radiation doses high enough to cause deterministic
2090    effects should be guided by recommendations from appropriate advisory bodies, medical
2091    specialty societies, and other organizations, and by current practice (ACR 2008c; Baiter and
2092    Moses 2007; Stecker et al. 2009).  For these patients, this includes justifying and documenting
2093    the high radiation dose in their medical record, notifying the patient or their health care proxy
2094    (legally authorized representative) of the radiation dose that has been administered and the likely
2095    consequences, and follow-up by the physician who performed the procedure to determine
2096    whether a skin injury has occurred (Baiter et al. 2010).
2098    Device related deaths, including those related to radiation dose, must be reported by the  device
2099    user facility to the device manufacturer and to the Food and Drug Administration in accordance
2100    with 21 CFR 803 (FDA2012b). Device-related serious injuries, including those resulting from
2101    radiation, must be reported by the device user facility to the device manufacturer or, if the
2102    manufacturer is unknown, to the Food and Drug Administration.  A serious injury is one that is
2103    life-threatening, results in permanent impairment of a body function or permanent damage to a
2104    body structure, or necessitates medical or surgical intervention to preclude permanent damage or
2105    impairment (FDA 2012a). If a patient's skin receives an absorbed dose that meets the Joint
2106    Commission definition of a reviewable sentinel event from a fluoroscopically guided procedure,
2107    or a dose likely to result in a serious injury, the event also should be reported to the Radiation
2108    Safety Officer and the facility's Patient Safety Manager, or designee (Baiter and Miller 2007;


                                          DRAFT PROPOSAL

2109    The Joint Commission 2006).
2111                  Quality process
2113    All QA/QI programs for interventional fluoroscopy should include patient radiation safety
2114    aspects. These include evaluation of operator performance in dose optimization and of
2115    procedures where patients received a radiation dose that caused a radiation injury.
2117    A review of radiation doses delivered to patients during fluoroscopically guided interventional
2118    procedures is an essential aspect of any performance improvement program.  The dose metrics
2119    for all procedures should be reviewed at intervals (quarterly, for example) for their magnitude
2120    and for the dose distribution of these cases. This will provide a picture of dose utilization; any
2121    abnormally high doses can be reviewed for appropriateness. For example, doses can be
2122    compared to available reference levels.  Any recommendations and actions for improvement
2123    should then be implemented.
2125    Analysis of overall dosimetric performance for interventional fluoroscopy procedures,
2126    incorporating the effects of equipment function, procedure protocols, and operator performance,
2127    requires a different process than the reference levels (RLs) used for radiography (NCRP 2010).
2128    It also requires a more detailed presentation of the reference data set. Guidance data for an
2129    interventional fluoroscopy  procedure are generated by obtaining data for all instances of that
2130    procedure from a number of different facilities.  These data are used to generate Guidance Levels
2131    (GLs), which are similar to the RLs used for radiography. The guidance data set includes the
2132    data for all instances of the procedure at each facility. This differs from the data set used to
2133    generate RLs, which typically includes only a single datum from each facility.
2135    Guidance  data sets for interventional fluoroscopy procedures usually demonstrate a lognormal
2136    distribution. The high dose tail is of particular interest, because this tail represents the cases
2137    where doses may be high enough to cause deterministic effects. Because differences between
2138    the shapes of the collected  guidance data and the local facility data are potentially useful, the
2139    FGI-procedure guidance data set should characterize the entire distribution, rather than just the
2140    10th and 75th percentile values typically used for radiography RLs.  Also, in order to provide a
2141    basis for comparison for facilities that use locally derived substantial radiation dose levels
2142    (NCRP 2010; Stecker et al. 2009), these data sets should indicate the percentage of instances of
2143    each procedure that exceed specific radiation dose levels. Ideally, these percentages should be
2144    presented  at 0.5 Gy intervals from 2 Gy to the maximum value observed in the data set.
2146    Guidance  data and GLs can be used, to some extent, in a fashion similar to RLs, but the
2147    lognormal shape of dose distributions for interventional fluoroscopy procedures mandates that
2148    the local median (50th percentile) be used for comparison with the guidance data, rather than the
2149    local mean dose. Also, high-dose interventional fluoroscopy cases require further evaluation.  It
2150    is possible for the facility's median dose for a procedure to be within an acceptable range (below
2151    the 75th percentile of the guidance data) at the same time that there are an excessive number of
2152    cases with a radiation dose greater than the 95th percentile of the guidance data. It is necessary to
2153    compare the percentage of cases at the facility that exceed the local substantial  radiation dose
2154    level (the radiation dose level that triggers radiation follow-up) with the percentage of cases in


                                          DRAFT PROPOSAL

2155    the guidance data that exceed the same level. Local percentages that are markedly above or
2156    below the value obtained from the guidance data should be investigated (NCRP 2010).
2158    The following method, using cumulative air kerma as the radiation dose metric, is suggested as
2159    one method of evaluating dose utilization for interventional fluoroscopy procedures (NCRP
2160    2010).  It is not the only possible method. Kerma-area product could also be used to evaluate
2161    general dose performance.  Kerma-area product can be used to evaluate operator performance
2162    with respect to collimation.  However, it does not provide an unambiguous identification of the
2163    cases where a very high skin dose may result in deterministic effects.
2165    An appropriate published guidance data set for the selected procedure (the guidance data) is used
2166    as the starting point, although published guidance data for FGI procedures are sparse as of 2012
2167    (Baiter et al. 2008; Bleeser et al. 2008; Brambilla et al. 2004; IAEA 2009; Miller et al. 2009;
2168    Vano et al. 2008a; Vano et al. 2009).
2170    A facility should judge its dose performance for interventional fluoroscopy procedures in several
2171    steps.  The first step is to compare the local substantial dose radiation level to the guidance  data.
2172    The facility's local substantial radiation dose level is either a value taken from the literature
2173    (ACR 2008c; Mahesh 2008; Stecker et al. 2009) or a locally determined value.  The percentage
2174    of procedures in the guidance data set that exceed this value can now be determined.
2176    The next  step is to characterize the dose distribution for all instances of a specific procedure
2177    performed at the facility. Evaluation of subsets of these data sorted by procedure room and
2178    operator can be useful as well, as discussed below. The percentage of instances exceeding  the
2179    local substantial radiation dose level, and the median value of the entire local data set (and
2180    appropriate subsets) is calculated.
2182    The local median can be compared with the 10th, 50th (median) and 75th percentiles of the
2183    guidance data.  A median value below the 10th percentile  of the guidance data may indicate
2184    incomplete procedures.  A median value between the 50th and 75th percentile of the guidance data
2185    could be due to clinical differences between the guidance data population and the local facility
2186    population or other factors.  Understanding the relevant reasons may be useful.  An investigation
2187    is warranted if the local median exceeds the 75th percentile of the guidance data (IAEA 2009;
2188    NCRP 2010). This step is analogous to the analysis performed using RLs for radiographic
2189    examinations.
2191    The percentage of instances exceeding the local substantial radiation dose level can be compared
2192    to the percentage of instances exceeding the substantial radiation dose level in the guidance data.
2193    Local percentages significantly above or below the value  obtained from the guidance  data should
2194    be investigated.
2196    It can be useful to perform the same analysis using a reference dose value of 3 Gy as well as the
2197    local substantial radiation dose level. An interventional fluoroscopy procedure is in the
2198    potentially-high radiation dose category if more than 5% of instances of that procedure exceed a
2199    reference dose of 3 Gy (NCRP 2010). If fewer than 5% of the instances of the procedure at the
2200    local facility exceed this value, then the procedure, as performed at the local facility, is not  in


                                          DRAFT PROPOSAL

2201    that category. At that local facility, the procedure may be performed safely in a fluoroscopy
2202    suite that does not meet the requirements of IEC 60601-2-43 (IEC 2010). Also, those procedures
2203    at the local facility that are not in the potentially-high radiation dose category may be audited
2204    less frequently than those that are in that category.
2206    Lastly, the overall distribution of the local  data may be compared to the distribution of the
2207    guidance data. Displacement or distortion of the local distribution histogram relative to the
2208    guidance data may be due to differences in equipment, clinical complexity, or other factors.
2210    The analysis may be extended to individual operators or interventional fluoroscopy procedure
2211    rooms by comparing operator- or room-specific data to either a facility's local distributions or to
2212    pooled distributions of data for multiple facilities (e.g., (Miller et al. 2009)).  Care should be
2213    taken in such an analysis to account for statistical interactions (e.g.,  statistical confounding
2214    between the operator and the interventional fluoroscopy procedure room).
2216    Procedures resulting in a substantial patient radiation dose should be reviewed on a regular basis.
2217    Reported potential radiation injuries should be reviewed at the regular QA meeting, with any
2218    available diagnoses, planned patient follow-up, and outcomes. If a radiation injury occurred, the
2219    procedure should be reviewed for appropriate use of radiation in the clinical context. It may be
2220    appropriate to periodically re-report on the status of known radiation injuries. Additionally,
2221    reporting of these cases to the institution's Radiation Safety Officer is desirable.
2223                 Staff safety
2225    Other than the patient who is being examined, only staff and ancillary personnel required for the
2226    procedure, or those in training, should be in the room during the  fluoroscopic examination. No
2227    body part of any staffer ancillary personnel involved in a fluoroscopic examination should be in
2228    the primary beam (Miller et al. 2010b). If primary  beam exposure is unavoidable, it should be
2229    minimized. As required by various states,  all personnel in the room during fluoroscopic
2230    procedures should be protected from scatter radiation by  either protective aprons or whole-body
2231    shields of not less than 0.25 mm of lead-equivalent material. An apron with lead equivalence of
2232    at least 0.35 mm is recommended.  Thyroid and eyes  should be protected if the potential
2233    exposure to the worker will exceed 25% of the annual regulatory dose limits  for those organs.  It
2234    is strongly recommended that protective aprons and gloves be  evaluated at least annually for lead
2235    protection integrity (Miller et al. 2010b; NCRP 2010).
2237    Pregnant individuals involved in fluoroscopically guided procedures generally do not need to
2238    limit their time in the procedure room to remain below the dose limit for the embryo and fetus, as
2239    long as they use appropriate protective garments and radiation protection methods, and their
2240    occupational exposure is adequately monitored (NCRP 2010).

                                         DRAFT PROPOSAL

2246    Computed tomography (CT) is an imaging modality that utilizes one or more x-ray beams to
2247    acquire projection images from many angles around the patient. The projection images are
2248    mathematically manipulated to obtain tomographic images that depict x-ray attenuation in a two
2249    dimensional cross sectional, project! onal or three dimensional representation of the subject's
2250    anatomy.
2252    There have been important technological advances that have greatly increased the clinical
2253    usefulness of CT imaging.  However, these improvements have also led to increased use of CT,
2254    imaging of larger volumes of the body, and acquiring an increased number of image sequences
2255    either during the various phases of tissue enhancement following contrast injection or to
2256    dynamically evaluate areas affected by motion.  These are incredibly powerful diagnostic tools
2257    that are invaluable to patient management and allow the elimination of more dangerous invasive
2258    procedures, such as exploratory surgery. But with this great benefit has come a price: there has
2259    been an increase in radiation dose to  the population, as well as to the individual patient.
2261    In the U. S., the number of CT procedures performed annually increased by 10% to 11 % per year
2262    from 1993 to 2006 (NCRP 2009). Although CT procedures comprise only about 17 % of all
2263    medical x-ray imaging procedures, they now impart about 49 % of the cumulative  effective dose
2264    from medical procedures received by the population of the U.S. (Mettler et al. 2008). As of
2265    2012, a typical  single CT imaging procedure of the chest, abdomen, or pelvis of an adult imparts
2266    an effective dose on the order  of 3-7  mSv (McCollough 2008; Mettler et al. 2008). These values
2267    are for single phase exams and the effective doses for multiple phase exams are correspondingly
2268    larger. Thus, CT imparts some of the largest doses per procedure in diagnostic medical imaging.
2269    These doses are significantly exceeded only by the doses from some complex fluoroscopically-
2270    guided interventional procedures.
2272    Except in the extreme circumstance of multiple irradiations of the same anatomic region, the
2273    doses from CT  examinations are unlikely to cause deterministic effects such as erythema or
2274    epilation (hair loss). Instead, the main concern is stochastic effects, particularly cancer. The risk
2275    to the patient is determined mainly by the doses to organs in or near the scanned portion of the
2276    patient, the age and gender of the patient, and the likely remaining lifespan of the patient.
2278    In 2001, it was  reported that standard adult technique factors were commonly used for CT
2279    imaging of patients in the U.S. regardless of body habitus, including children and even infants
2280    (Brenner etal. 2001; Paterson et al. 2001).  If adult technique factors are used for imaging the
2281    abdomen or thorax of a small child or infant, the larger doses together with the larger risk of
2282    cancer per unit  dose is estimated to pose a risk of fatal cancer on the order of one per thousand
2283    examinations (Brenner et al. 2001).  Therefore, it is essential to optimize dose when imaging
2284    children (FDA 2001). Of the many methods for adjusting CT techniques for children, perhaps
2285    the simplest and most widely used techniques utilizes the Breslow method familiar to clinical
2286    providers as a way to estimate the weight, drug dosing, and equipment sizing for children.  Many
2287    sites have developed specific CT protocols that adjust the kVp and mAs based on the
2288    approximate size of a child matching each Breslow color scheme category. Professional

                                         DRAFT PROPOSAL

2289    societies provide excellent guidance on imaging, such as the "Image Gently" campaign (Goske
2290    MJ et al. 2008; Strauss et al. 2010).
2292    Many advances in CT technique and technology have been specifically targeted at reduction of
2293    the radiation dose delivered to the patient during CT examinations. To be effective, these
2294    techniques must be used, and used properly.  It is imperative that Radiological Medical
2295    Practitioners, physicists, and technologists involved in CT imaging keep abreast of current
2296    developments and utilize all techniques available to them to reduce the patient's radiation
2297    exposure as much as possible while obtaining the clinically needed information.
2299          Equipment
2301    CT was introduced in the mid-1970s. For several decades, a constant x-ray tube current was the
2302    only available technology for performing a CT examination. Tube current did not change,
2303    regardless of the angle of the x-ray beam as the x-ray tube rotated around the patient, and
2304    regardless of the attenuation along the path of the beam through the patient. However, this
2305    attenuation varies greatly with the angle of the beam and the location on the patient's body.  As
2306    of 2012, developments in technology allow automated tube current modulation,  providing
2307    similar image  quality with lower radiation dose. Facilities should use equipment that provides
2308    relevant patient dose information.  This equipment should allow the facility to program in dose
2309    alerts to inform operators if selected operating parameters might produce a radiation dose
2310    exceeding that recommended by the facility. Equipment manufacturers should incorporate these
2311    features into the equipment.
2313    The dose of radiation to a patient, in conjunction with the attenuation provided by the part of the
2314    patient that is  scanned and the presence or absence of IV contrast, determines the signal-to-noise
2315    ratio in the resultant images. The signal-to-noise ratio needed for diagnostic confidence depends
2316    upon the diagnostic task. Smaller and thinner patients require smaller doses than larger and
2317    thicker patients to produce similar signal to noise ratios in the images.  Imaging procedures to
2318    detect or assess larger structures and structures with more inherent or enhanced contrast
2319    (difference in  density) require a smaller dose than imaging procedures to detect or assess smaller
2320    structures and those with less inherent contrast.
2322    Stand-alone CT scanners have been complemented  by the development of hybrid modalities such
2323    as Positron Emission Tomography/CT [PET/CT] and Single Photon Emission Computed
2324    Tomography/CT [SPECT/CT]. These hybrid modalities use two equipment components to
2325    acquire two types of images of a patient in the same setting, without changing the patient's
2326    position on the imaging system table.  This allows co-registration of image data so that the
2327    anatomic detail provided by one imaging modality can be matched to the physiologic marker
2328    capability of the second modality to provide more specific information about the location and
2329    extent of disease. These CT devices may be operated at lower doses if the CT portions of the
2330    exams are not intended to be used for diagnosis independent of the SPECT or PET exam.
2332    Technological development in image reconstruction, increases in computer processor power,
2333    equipment innovation, and optimization techniques in general have led to a marked increase in
2334    the ability to obtain adequate quality images at lower patient doses. These improvements should


                                         DRAFT PROPOSAL

2335    be implemented to the fullest extent practicable. Facilities should use equipment that provides
2336    relevant patient dose information. This equipment should allow the facility to program in dose
2337    alerts to inform operators if selected operating parameters might produce a radiation dose
2338    exceeding that recommended by the facility.  Equipment manufacturers should incorporate these
2339    features into the equipment.
2341           Testing and Quality Assurance
2343    Equipment testing for quality assurance should be performed after installation but before first
2344    clinical use, annually thereafter, and after each repair or modification that may affect patient dose
2345    or image quality.  Testing should be performed as specified in the section of this document
2346    entitled Technical Quality Assurance in Medical Imaging with X-Rays.  In addition, the
2347    recommendations found in the current version of ICRP Publication 102 (NCRP 1989b) should be
2348    followed when applicable.
2350    A quality control  program should be established. The program should conform to the ACR
2351    Technical Standard for the Diagnostic Medical Physics Performance Monitoring of Computed
2352    Tomography (CT) Equipment or equivalent guidance.
2354           Personnel
2356    A CT system should only be operated by a Radiologic Technologist registered by the American
2357    Registry of Radiological Technologists (ARRT) or equivalent, preferably with advanced
2358    certification in CT, operating under the supervision of a Radiological Medical Practitioner with
2359    appropriate training in CT physics, radiation  safety and CT image interpretation.
2361    Ideally, a PET/CT or SPECT/CT should be operated by a technologist certified in both nuclear
2362    medicine and CT.  However, a PET/CT or SPECT/CT may also be operated by a nuclear
2363    medicine technologist with Certified Nuclear Medicine Technologist (CNMT) or Radiological
2364    Technologist Nuclear qualified (RT(N)) certification and additional training in CT imaging
2365    sufficient to safely operate a CT system.  Alternatively, a PET/CT may be operated by a
2366    technologist who  is qualified to operate a CT system and who also has additional training in PET
2367    imaging sufficient to safely operate a PET  system.  If a technologist who meets these
2368    requirements is not available, the PET/CT or SPECT/CT system should be operated by two
2369    technologists, one a nuclear medicine technologist qualified to operate the PET or SPECT
2370    system and the other a Diagnostic Radiological Technologist (DRT) or a therapist in radiation
2371    oncology who is qualified to operate the CT system.  Utilization and training requirements for
2372    the operation of other hybrid modalities should be evaluated as new combinations of modalities
2373    emerge.
2375           Procedures
2377    One of the most effective ways to optimize the dose of radiation delivered to the patient in a CT
2378    study is to tailor the study to the patient's specific needs.

                                          DRAFT PROPOSAL

2380    A CT protocol specifies the parameters for the image acquisition and largely determines the dose
2381    to the patient. It defines the portion of the patient's anatomy to be imaged, whether and how
2382    contrast agents will be administered, the number and timing of imaging sequences, and
2383    acquisition technical parameters. Imaging sequences in a multiphase study may include several
2384    phases, such as a pre-contrast phase, an arterial phase, a venous phase and/or a delayed phase.
2385    Acquisition technical parameters may include pitch, collimation (beam width), kV, mA (constant
2386    or modulated), rotation time, physiologic gating, image quality factors, and reconstruction
2387    method. In addition:
2388     1.   In some cases, the kV may be adjusted for the type of examination (e.g., contrast enhanced
2389         angiography) to accommodate patient size.
2390     2.   If constant mA is selected, the protocol should utilize a chart for adjusting the mA for the
2391         patient's size (girth or thickness).  If mA modulation is selected, the protocol should specify
2392         the parameters determining the balance between image noise and patient dose.
2393     3.   Organ-specific tube current modulation, where available, technically feasible, and clinically
2394         appropriate, should be considered to protect organs such as the breast in younger female
2395         patients and the lens of the eye.
2396     4.   Where applicable, the prescription of image acquisition technique factors should take into
2397         account the availability of advanced image reconstruction techniques to decrease the
2398         required patient dose.
2399     5.   Once the image sequence is acquired, the user can select alternative reconstruction
2400         parameters (e.g., reconstructed slice thickness) to  view the images differently without
2401         having to rescan the patient.
2403    Each CT protocol should be documented in two ways.  The first way is a document detailing all
2404    relevant information.  The second way provides a more limited subset of programmable
2405    information, primarily acquisition parameters, stored on the imaging device.
2407    It is important to image only the area of anatomy in question and acquire only the necessary
2408    sequences.  This is accomplished by determining the imaging protocol for the examination.
2409    Where appropriate, the radiological medical practitioner should select and adjust the protocol to
2410    ensure that the patient is examined using the appropriate techniques and dose.
2412    The technologist performing the study is responsible for limiting the length of the patient being
2413    scanned to the minimum clinically necessary.  The technologist is also responsible for setting up
2414    the CT system so that the correct protocol is used and the imaging parameters are appropriate for
2415    the patient's size, age, and intended examination.  Before performing the study, the technologist
2416    should confirm that the technical parameters and the radiation dose metric are appropriate for the
2417    patient and planned study. If existing equipment does not provide a dose metric, efforts should
2418    be made to upgrade or replace it. To prevent accidental overexposure, the projected dose should
2419    correspond to the doses normally associated with the protocol, within reasonable variability.
2420    This should be confirmed again after the patient has been scanned.
2422    Optimization of CT protocols is important for minimizing patient dose.  The facility's standard
2423    protocols for CT imaging  should be reviewed by a team, including a physician expert in CT
2424    image interpretation, a technologist expert in performing CT examinations, and a qualified
2425    physicist:


                                          DRAFT PROPOSAL

2426     1.   when the protocol is developed,
2427     2.   when the protocol is significantly modified,
2428     3.   on a regular basis (preferably annually), and
2429     4.   after an equipment upgrade or replacement.
2431    It is strongly recommended that procedures be established to avoid inadvertent or unapproved
2432    modification of CT protocols.  Methods, such as limiting access through the use of passwords,
2433    should be adopted to implement these procedures.  Superseded protocols should be archived for
2434    future reference.
2436    Reviews and revisions should align protocols with current clinical practice, evaluate the
2437    magnitude of delivered radiation doses, and optimize the radiation dose. Modifications of the
2438    protocol to suit the needs of an individual patient generally do not require a specific review, but
2439    the impact on radiation dose should be understood and considered.
2441    Operator selectable parameters on CT scanners that affect the dose to the patient include the
2442    voltage applied to the x-ray tube (kV), the x-ray tube current (mA) or current-time product per
2443    x-ray tube rotation (mAs), and the pitch (incremental table movement per x-ray tube rotation
2444    divided by the nominal x-ray beam width at isocenter).  The radiation dose to the patient within
2445    the scanned volume is approximately proportional to the square of the kV and is proportional to
2446    the effective mAs (the mAs divided by the pitch). Technique factors should be appropriate for
2447    the size (and not just the age) of the patient and the body part being imaged.  In particular, adult
2448    technique factors should not be used for children and infants.  Technique factors should be
2449    chosen that produce a diagnostically adequate image rather than a "perfect image," thus
2450    matching the radiation exposure to the diagnostic requirement. If available on the  CT scanner,
2451    automated modulation of the tube current should be used for those procedures for which it
2452    produces substantial dose savings, e.g., scans of the thorax.  Using this  feature appropriately can
2453    reduce dose significantly, whereas errors in its use have produced substantial increases in dose.
2454    For gated cardiac CT imaging, utilize (when available) the feature that reduces or terminates the
2455    beam current during portions of the cardiac cycle that will not be used for image reconstruction
2456    (ICRP2012).
2458    Several phantom-derived dose indices specific to CT have been defined. These can be useful to
2459    compare one study protocol to another in the assessment of benefit and risk; these  are described
2460    in the literature (McNitt-Gray 2002).  Two indices in common use are the volumetric computed
2461    tomography dose index (CTDIyoL), which is approximately the average dose in the scanned
2462    volume, and the dose-length product (DLP), defined as the CTDIvoL multiplied by the scanned
2463    length. These indices indicate the radiation exposure delivered by the CT scanner  to a phantom,
2464    not the specific radiation energy (i.e., dose) received by any patient. Both of these measures may
2465    be available from current CT scanners, and future devices may incorporate more accurate and
2466    useful dose metrics.  The DLP and the portion of the patient that is scanned (e.g., head, thorax, or
2467    abdomen) may be used to estimate the effective dose to the patient.  Effective dose is an
2468    indicator of stochastic risk. CT dose indices should be recorded as part of the patient record in
2469    the imaging study or medical record.

                                         DRAFT PROPOSAL

2473    Bone densitometry noninvasively measures certain physical characteristics of bone that reflect
2474    bone strength, typically reported as bone mineral content or bone mineral density. It is used for
2475    diagnosing osteoporosis and estimating fracture risk. It is also used to monitor changes in bone
2476    mineral content, whether from age, conditions causing bone mineral loss, or treatment. Devices
2477    that measure bone mineral content are called bone densitometers. Non-invasive methods for
2478    measuring bone mineral content are based on the transmission of x-rays or gamma rays through
2479    the bone.  The radiation beams can be produced as pencil or fan beams.  The advantage of the
2480    latter is that it is faster, but the radiation dose is increased by a factor of about 4.
2482    There are also devices that use the transmission of sound waves through bone to assess bone
2483    structure.  These are ultrasound devices that do not directly measure bone mineral content, but
2484    are also commonly called densitometers.
2486           Equipment
2488    The principal methods in routine clinical use in 2012 for the non-invasive measurement of bone
2489    mineral content using ionizing radiation include:  x-ray  absorptiometry and quantitative x-ray
2490    computed tomography (QCT).  X-ray absorptiometers measure attenuation of two x-ray beams
2491    of well-separated average photon energies to discriminate between bone mineral and soft tissue.
2492    This method is called dual-energy x-ray absorptiometry (DXA or DEXA). The other principal
2493    method for assessment of bone structure regarding osteoporosis is quantitative ultrasound (QUS)
2494    (ACR 2008a; Bonnick and L. 2006).
2496    Of all the methodologies available in 2012, DXA is the only one that can be used to make a
2497    diagnosis of osteoporosis.  The World Health Organization has developed criteria for diagnosing
2498    normal bone density, osteopenia, and osteoporosis (Kanis et al.  1994). This classification is
2499    specific for DXA (total hip or femur and neck, PA lumbar vertebrae, or distal 1/3 radius)  and
2500    cannot be applied to any other technology (ISCD 2007a; ISCD 2007b).  As of 2012, DXA is also
2501    the most commonly used technology for monitoring changes in  bone mineral density (BMD).
2502    QCT is sometimes used to monitor changes in the trabecular portion of the vertebrae when there
2503    is a need to measure changes more frequently than with DXA. QCT,  nevertheless, involves a
2504    much higher exposure to radiation, especially if done sequentially, and is more expensive and
2505    requires more specialized equipment and staff expertise than DXA.
2507    Bone mineral can be assessed non-invasively by these methods at several sites in the axial and
2508    appendicular skeleton.  DXA is most commonly used to assess the lumbar spine, proximal
2509    femurs, and distal radii.  DXA measurements of the thoracic spine cannot be performed because
2510    the ribs overlap the thoracic vertebrae.  Measurements of the proximal femurs are commonly
2511    referred to as "hip" measurements, but the bone mineral content measurements themselves are
2512    limited to the proximal femurs. DXA and SXA devices are available  for measurements of
2513    peripheral sites such as the radius and the calcaneus. The standard evaluation of bone mineral
2514    density includes evaluation of at least one proximal femur and the lumbar spine in the frontal
2515    plane.


                                         DRAFT PROPOSAL

2517    Some DXA devices are also capable of imaging the spine to detect vertebral fractures.  This is
2518    called vertebral fracture assessment (VFA). Detection of vertebral compression fractures is an
2519    independent method for diagnosing osteoporosis. This is performed with imaging of the thoracic
2520    and lumbar spine in the lateral plane. Exposure to radiation is higher with VFA than with DXA
2521    but still considerably lower than for conventional radiography of the same area (Genant et al.
2522    1996).
2524    Some DXA devices allow the C-arm holding the x-ray tube and detector to rotate to a position
2525    permitting lateral bone mineral density measurements of the lumbar spine in the supine patient,
2526    in addition to the usual PA or AP measurements.  Some DXA devices permit the acquisition of
2527    projection images of the entire lateral spine for vertebral morphometry. Furthermore, some
2528    DXA devices permit PA or AP scans of the entire body for body composition analysis, providing
2529    an estimation of total bone mineral mass, lean body mass, and fat mass.
2531    QCT measurements are usually performed of the lumbar spine, but there are options to perform
2532    measurements at other anatomical sites as well. Unlike DXA, QCT is able to differentiate
2533    mineral content in the bone as opposed to mineral content outside bones,  such as in osteophytes
2534    or aortic calcifications. The presence of these extra-osseous calcifications makes the use of
2535    DXA of the vertebrae less reliable in older people. QCT, on the other hand, is able to focus on
2536    the trabecular or cortical component of bone. QCT may be performed with a standard CT
2537    system; however, a special phantom and software are needed.  QUS is used to measure sites in
2538    the append!cular skeleton, most commonly the calcaneus.
2540           Testing and Quality Assurance
2542    Each facility performing bone densitometry should have a quality assurance program. The
2543    procedures for this program should be documented in writing.  The program should conform to
2544    manufacturer's recommendations and recommendations of professional societies such as the
2545    International Society for Clinical Densitometry (ISCD) and the American College of Radiology.
2547    The quality assurance program should include daily assessments of accuracy and periodic
2548    assessments of precision.  Cross calibration should be performed whenever the densitometer is
2549    repaired, modified, or replaced.  This helps ensure proper measurement of bone mineral content,
2550    detection of osteoporosis, estimation of fracture risk, and changes over short and long periods of
2551    time (i.e., minutes and years) even as equipment is repaired, modified, or replaced.
2553                 Accuracy  check
2555    Accuracy is the degree to which a measurement value estimates the actual value of the quantity
2556    being measured. The test for accuracy primarily measures equipment characteristics.  Most
2557    densitometers will not allow a DXA scan to be performed unless the accuracy test is passed.
2558    Phantoms are available and an accuracy assessment should be obtained daily.


                                          DRAFT PROPOSAL

2563                  Precision
2565    Precision is the degree to which the same value is obtained when a measurement is repeated
2566    (Bonnick and L. 2006; ISCD 2012).  The better the precision, the smaller the Least Significant
2567    Change (LSC), and the more likely is the detection of small changes in BMD. Precision studies
2568    assess the technologist's skills at positioning the patient reproducibly.  Several patient factors
2569    affect positioning, including obesity, arthropathies, pain, deformities, fractures, and other
2570    conditions limiting patient mobility.  Phantoms are not available for assessing precision; this is
2571    due to the complexity of relating phantom data to patient results.  Given these clinical variables
2572    and lack of appropriate phantom, precision studies should be conducted on subjects who are
2573    representative of the bulk of the population scanned at the particular facility. For instance, if
2574    most patients scanned in a facility are over the age of 65 years, precision studies should not be
2575    done in that facility on young athletes.  Each facility should establish a range of acceptable
2576    precision performance and ensure that each technologist meets this standard. If a facility has
2577    more than one technologist,  an average precision error combining data from  all technologists
2578    should be used to establish precision error and LSC for the facility.
2580    For DXA, precision is affected by the positioning of patients. Therefore, precision assessments
2581    should be performed using repeated measurements of patients, with repositioning of the patients
2582    between measurements. Precision studies can be done on either 30  patients scanned twice (after
2583    the patient is repositioned in between scans) or 15 patients scanned 3 times, also after
2584    repositioning in between each scan (ISCD 2012).  The technician's or facility's precision is then
2585    used to calculate the Least Significant Change (LSC) to determine whether an observed change
2586    in BMD over a period of time is significant (higher than LSC) or not (less than the LSC). The
2587    patients imaged for precision studies should be representative of the facility's patient  population.
2588    Retraining should occur if a technologist's precision is worse than values recommended by
2589    professional societies, e.g., ACR and ISCD.
2591                  Cross calibration
2593    Cross-calibration is a method to derive equivalent BMD values when measured on the original
2594    densitometer and a modified or new densitometer.  Cross-calibration should  be performed when
2595    repairing, modifying, or replacing the entire system or any portion of the system that might alter
2596    the absolute BMD value.  The old and new densitometers should be cross-calibrated to establish
2597    a new baseline. As with precision assessments, phantoms are not available for cross calibration.
2598    Cross-calibration is conducted in-vivo by scanning 60 to 100 patients with a  wide  range of bone
2599    densities (normal to osteoporosis) on both the old and new densitometer. A cross-calibration
2600    equation is then developed (by using linear regression methods), and can be used to predict the
2601    BMD value on the different densitometer.
2603                  Justification for quality assurance studies
2605    Patients enrolled in precision studies benefit indirectly and may benefit directly because these
2606    studies improve the reliability of the results.  Patients enrolled in cross calibration  studies benefit
2607    directly in that these processes allow a better comparison with future scans done on the same or
2608    different  equipment.  It is in a patient's best interest to be scanned in a facility where precision is


                                          DRAFT PROPOSAL

2609    high and LSC small, as the results are more reliable and comparisons with other scans more
2610    meaningful.
2612    Precision and cross-calibration studies conducted by scanning patients are not research. Thus,
2613    these studies do not need approval of an institutional review board.  However, the facility should
2614    obtain informed consent from each patient participating in a precision or cross-calibration study.
2615    Although each scan results in a low effective dose to the individual patient, radiation doses to the
2616    individual patient can be reduced by scanning a larger number of patients a fewer number of
2617    times and by not including a patient in both precision and cross-calibration studies.  Patients or
2618    staff should not be scanned solely for the purpose of training.
2620    Cross-calibration should be performed when changing the entire system or any portion of the
2621    system that might alter the absolute BMD value.
2623    Patient radiation dose should be determined by a qualified physicist or a qualified medical health
2624    physicist after installation, after service that may affect the radiation dose, and at least annually
2625    thereafter.
2627    In most cases, structural shielding will not be required for DXA or SXA devices or for QCT
2628    devices designed for use only on the append!cular skeleton.  Nonetheless, the radiation safety
2629    officer or a qualified physicist should make a determination whether shielding is needed. After
2630    device installation, whether or not additional shielding is installed, dose measurements should be
2631    made in adjacent areas and at the operator's station (which may be inside the room) and should
2632    be documented in a written report. This will help determine the need for occupational  dosimetry
2633    and provide a historical record to ensure proper equipment functioning.
2635           Personnel
2637    Technologists performing absorptiometry should have documented formal training in the use  of
263 8    the absorptiometry equipment they are operating, including performance of all manufacturer -
2639    specified and facility quality assurance (QA) procedures.  Each person performing bone
2640    densitometry should meet the State licensing requirements in addition to at least one of the
2641    following qualifications:
2642     1.  be a Diagnostic Radiologic Technologist (DRT),
2643     2.  be certified by the American Registry of Radiologic Technologists (ARRT) in Nuclear
2644        Medicine Technology,
2645     3.  be certified by the Nuclear Medicine Technology Certification Board,
2646     4.  be certified by the International  Society of Clinical Densitometry as a Certified
2647        Densitometry Technologist,
2648     5.  have ARRT post-primary certification in Bone Densitometry, or
2649     6.  have state licensure or limited licensure in Bone Mineral Densitometry, when the licensure
2650        requires successful completion of the ARRT Limited Scope Bone Densitometry
2651        Exami nati on.

                                          DRAFT PROPOSAL

2653    Interpretation of the results is important and the interpreting Radiological Medical Practitioner
2654    should be knowledgable in bone densitometry.  Reliance on the report generated by the
2655    equipment alone is inadequate.  Clinicians should also examine the plates and raw data.
2657          Procedures
2659    Organizations that use bone densitometry should refer to current versions of procedures or
2660    position statements issued by professional organizations (ISCD 2007a; ISCD 2007b). The
2661    following guidance applies to DXA scans.
2663    Before the DXA scan, the technologist should:
2664     1.   Ensure that the various quality assurance parameters have been fulfilled.
2665     2.   Verify that there are no contraindications to the DXA scans.  Pregnant patients or patients
2666         likely to be pregnant should not have a DXA scan. It is also not recommended to scan
2667         patients  whose weight exceeds the weight limit of the densitometer as the results may not
2668         be accurate and the densitometer table may be damaged.
2669     3.   Verify that there are no artifacts. Patients who have a prosthetic hip or orthopedic device in
2670         the lumbar vertebrae should not have this part of the body scanned. It is also recommended
2671         not to scan patients who have taken calcium supplements the day of the scan as the calcium
2672         tablet may be in the path of the X-rays and artificially elevate the mineral content of the
2673         area scanned.  Similarly patients who have undergone radiological contrast studies on the
2674         abdomen should not be scanned until the contrast material is no longer in the patient's
2675         body. Patients should not have metallic objects on the parts  scanned,  including navel rings
2676         which interfere with the absorption of radiation.  Other common artifacts include zippers,
2677         buttons and wallets.
2678     4.   Enter and verify the accuracy of all the relevant patient demographic information, such as
2679         the age,  race, gender, weight and height. Any erroneous information will invalidate the
2680         subsequent calculation of the T- and Z-scores and hence the validity of the  scan.
2681     5.   Position the patient according to the criteria set by the manufacturer.  If it is not possible to
2682         position the patient as per the recommendations because the patient is unable to be placed
2683         in that position because of pain or limitation of movement, the technologist should make a
2684         note to that effect.
2685     6.   Note the scan mode (e.g., fan beam or pencil  beam) and the type of leg block used.
2687    During the DXA scan:
2688     1.   The patient must refrain from moving.
2689     2.   The technologist should:
2690         a.  Ascertain that the patient's positioning is  good. If the patient positioning is not as per
2691            the accepted recommendations, the subsequent analysis of the scan will not be valid.
2692         b.  Ascertain that there are no artifacts.
2693         c.  Ascertain that all the regions of interest are clearly visualized.
2694         d.  Stop the DXA scan and restart it if positioning is not adequate, if there are artifacts, or if
2695            the regions of interest are not clearly visualized.
2697    Analysis of the DXA scan:
2698     1.   Before the analysis, the technologist needs to ascertain that:


                                          DRAFT PROPOSAL

2699            a.  The patient's demographics are correctly noted.
2700            b.  The patient's positioning is good.
2701            c.  There are no artifacts.
2702            d.  The various regions of interest are clearly visualized.
2703     2.  During the analysis, the technologist will follow the manufacturer's recommended
2704         procedure to identify the various regions of interest.
2706    After the analysis the technologist will print out the results of the exam that would have been
2707    configured according to parameters set by the facility where the scans are done.
2709    Reporting the DXA scan results:
2710     1.  Reports are automatically generated by the equipment,  and should be modified to meet the
2711         needs of the facility where the scans are done. Other information also may be added such
2712         as risk factors for osteoporosis and fracture risk assessment FRAX scores for hips and other
2713         major fracture sites.  FRAX is the World Health Organization's (WHO's) Fracture
2714         Assessment Tool, a computer program used to estimate the probability of the patient
2715         sustaining a hip or other major osteoporotic fracture in  the following ten years (WHO 2004;
2716         WHO 2012).  Various models of reporting are also available from the International Society
2717         of Clinical Densitometry.  These may include information about recommended diagnostic
2718         tests and treatment options.  It is important however, to tailor the reports to the needs of the
2719         referring physicians.
2720     2.  Various report styles exist.  The ones preferred by the facility and which satisfy the needs
2721         of the referring physician should be used. Structured reports should be used if electronic
2722         records are maintained by the facility.

                                          DRAFT PROPOSAL

2724    DENTAL
2726    Diagnostic imaging is an integral part of dentistry.  Dental radiographs are estimated to
2727    contribute approximately one percent (0.006 mSv)  of the total population's effective dose. The
2728    daily background effective dose to a member of the U.S. general population is estimated to be
2729    3.0 mSv/365 = 0.008 mSv/day (NCRP 2009). As of 2012, there is no scientific or epidemiologic
2730    evidence to suggest that the effective dose to the U.S. population from dental diagnostic
2731    radiographic procedures estimated to be in the range of 0.006 mSv carries significant potential
2732    biological risk either at the population level, or individual level.
2734    The dental health-care worker's goal is to keep radiation exposures to the minimum necessary to
273 5    meet diagnostic requirements. In 2003, the NCRP updated its recommendations on radiation
2736    protection in dentistry (NCRP 2003). The Centers  for Disease Control and Prevention published
2737    its Guidelines for Infection Control in Dental Health-Care Settings in 2003, and the U.S. Food
2738    and Drug Administration along with the American Dental Association updated selection criteria
2739    for dental radiographs in 2004 (ADA FDA 2004; CDC 2003). In 2006, the American Dental
2740    Association published its practice recommendation for the use of dental radiographs .  All of
2741    these recommendations were considered when developing the following guidelines.
2743           Equipment
2745    It is strongly recommended that dental x-ray machine be capable of being operated in  at least the
2746    60-90 kVp range, with the x-ray beam filtration consistent with the FDA requirements ((FDA
2747    2012f) Table 1). It is also strongly recommended that the equipment be collimated with a lead-
2748    lined  40 cm (16 in) beam indicating device (BID) (NCRP 2003), which results in less beam
2749    divergence and less volume of patient's tissue irradiated per exposure. Utilization of rectangular
2750    collimation is recommended for intra-oral techniques.  This further restricts the beam to
2751    approximately the size of the film/imaging receptor being used (Gibbs 2000; NCRP 2003). Use
2752    of rectangular collimation reduces the exposed area to approximately 48% compared with round
2753    collimation.  This improves image quality by reducing scatter, resulting in a radiograph with
2754    better resolution and better contrast.
2756    The dental health professional (dentist or dental hygienist) has a  variety of image receptors to
2757    select from that include conventional film, along with evolving digital technology which include
2758    photostimulable imaging plates and digital imaging sensors. Although digital radiography offers
2759    a potential for significant dose reduction, the number of retakes (commonly due to poor
2760    positioning of the bulky sensors with encumbering  wire) may result in actual increased dose for
2761    the patient unless care is given to providing proper  training and the use of image receptor
2762    positioning devices.  Furthermore, due to the  smaller active area  of some sensors, more than one
2763    exposure may be required to cover the anatomical area imaged using  a single conventional film.
2764    Therefore, it is recommended that an image receptor positioning device be used with sensors,
2765    that specific and ongoing training be given to orient operators on ways to eliminate the need for
2766    retakes, and that technique charts provided by manufacturers be reviewed for proper sensor
2767    placement.

                                          DRAFT PROPOSAL

2769    In clinics or field use environments where film is still used, the fastest appropriate film should be
2770    used.  For periapical and bite-wing radiographs, only films of American National Standard
2771    Institute Speed Group "F" or faster are recommended (NCRP 2003). Since there are minimal
2772    diagnostic differences between the various intraoral films available in 2012, the use of faster
2773    films (E- or F-speed) is preferred because they reduce the radiation dose by more than 50% when
2774    compared with D-speed film.
2776    When panoramic and other extraoral projections are taken, it is recommended that high speed
2777    films be matched to their rare earth intensifying screens. The higher speed of the rare earth
2778    screen-film combinations (400 or higher system speed) are twice as fast as conventional calcium
2779    tungstate screen-film combinations with equivalent diagnostic value at  1/2 to 1/4 the dose to the
2780    patient (Miles et al. 1989).
2782    It is imperative that the operator's manual for all imaging acquisition hardware is readily
2783    available to the user, and that the equipment is operated and maintained following the
2784    manufacturer's instructions, including any appropriate adjustments for optimizing dose and
2785    image quality.
2787    Leaded aprons were recommended for dentistry when dental x-ray equipment was poorly
2788    collimated, unfiltered, and films were much slower than those available in 2012.  Given the
2789    advent of good collimation, filtration, direct current x-ray machines, faster film speeds, and
2790    digital sensors, gonadal and effective doses resulting from scatter radiation are extremely low
2791    and are not significantly reduced by the use of the leaded aprons.  According to NCRP Report
2792    No. 145 , technological advancements have eliminated the requirement for lead aprons on
2793    patients when all of the following recommendations are followed: a 60-80 kVp intraoral
2794    exposure unit is used, the source-to-image receptor distance for intraoral radiography is between
2795    20-40 cm, a rectangular collimator is used for intraoral radiographs, and a minimum of E-speed
2796    equivalent exposure film/sensors is used. It is not unreasonable to have aprons available for
2797    patients who request their use (NCRP 2003).
2799    The thyroid gland is among the most sensitive organs to radiation-induced tumors, especially in
2800    children. NCRP Report No. 145 states that, "thyroid shielding shall be provided  for children, and
2801    should be provided for adults, when it will not interfere with the examination" (NCRP 2003).
2802    These recommendations may be relaxed in the cases where anatomy or the inability of the
2803    patient to cooperate makes beam-receptor alignment awkward. The positive project! on-angle of
2804    the panoramic x-ray beam of+4° to +7 ° essentially eliminates thyroid dose.
2806    Protective aprons and thyroid shields should be hung or laid flat and never folded, and
2807    manufacturer's instructions should be followed. All protective shields  should be evaluated for
2808    damage (e.g., tears, folds, and cracks) at least annually using visual and manual inspection
2809    (Miller et al.  2010b). If a defect in the attenuating material is suspected, radiographic or
2810    fluoroscopic inspection may be performed as an alternative to immediately removing the item
2811    from service. Consideration should be given to minimizing the radiation exposure of inspectors
2812    by minimizing unnecessary fluoroscopy.

                                          DRAFT PROPOSAL

2814    As of 2012, hand-held, battery-powered x-ray systems are available for intra-oral radiographic
2815    imaging. The hand-held exposure device is activated by a trigger on the handle of the device.
2816    Device operation, at first glance, poses several concerns, which appear inconsistent with
2817    previously established dental radiological protection guidelines.  These concerns include: (1) the
2818    x-ray tube assembly is hand-held by the operator rather than wall mounted, (2) the trigger for x-
2819    ray exposure is on the hand-held device and not remotely located away from the source of
2820    radiation, and (3) the operator does not stand behind a barrier.  However, dosimetry studies
2821    indicate that these hand-held devices present no greater radiation risk than standard dental
2822    radiographic units to the patient or the operator (Goren et al. 2008; Masih et al. 2006; Witzel
2823    2008).  No additional radiation protection precautions are needed when the device is used
2824    according to the manufacturer's instructions. These include: (1) holding the device at mid-torso
2825    height, (2) orienting the shielding ring properly with respect to the operator, and (3) keeping the
2826    cone as close to the patient's face as practical. If the hand-held device is operated without the
2827    ring shield in place, it is recommended that the operator wear a lead apron.
2829    All operators of hand-held units should be instructed on their proper storage. Due to the portable
2830    nature of these devices, they should be secured properly when not in use to prevent accidental
2831    damage, theft or operation by an unauthorized user.  Hand held units should be stored in locked
2832    cabinets, locked storage rooms or locked work areas when not under the direct supervision of an
2833    individual authorized to use them.  Units with user-removable batteries should be stored with the
2834    batteries removed. Records listing the names of approved individuals who are granted access
2835    and use privileges should be prepared and kept current.
2837           Testing and Quality Assurance
2839    Quality assurance refers to those steps that are taken to make sure that a dental facility or
2840    imaging facility consistently produces images that are adequate for the purpose with  optimal
2841    patient and minimal  operator exposure.  Quality assurance may be divided into two major
2842    categories: quality administration and quality control. Quality administration refers to the
2843    management aspect of a quality assurance program.  It includes those organizational  steps taken
2844    to make sure that testing techniques are properly performed and that the results of tests are used
2845    to effectively maintain a consistently high level  of image quality. An effective program includes
2846    assigning personnel to determine optimum testing frequency of the imaging devices, evaluate
2847    test results,  schedule corrective action, provide training, and perform ongoing evaluation  and
2848    revision of the quality assurance program.
2850    Quality control comprises the procedures used for the routine physical testing of the primary
2851    components of the dental imaging chain from the x-ray machine, through processing, to the
2852    viewing of dental images. Quality control measures are listed in Table 2. Each facility, through
2853    its radiation quality control team (e.g. health physicist, medical physicist, biomedical
2854    maintenance personnel), needs to track maintenance and monitoring procedures.  Dental clinics
2855    that use film should  evaluate film processing darkrooms and daylight loaders for light leaks and
2856    safelight performance.

                                          DRAFT PROPOSAL

2859           Personnel
2861    As in general medical radiology, it is important to eliminate unproductive radiation exposure in
2862    dentistry; thus, privileges to order dental x-ray examinations should be limited to Doctors of
2863    Dental Surgery or Dental Medicine who are eligible for licensure in the United States or one of
2864    its territories or commonwealths.  Exception may be granted for persons in post graduate training
2865    status under the supervision of a person meeting such requirements. Variances to the above
2866    qualification requirements should occur only for emergency or life-threatening situations, such as
2867    natural disasters.  Also, non-peacetime operations in the field or aboard ship could require such
2868    variances. Dental equipment operators should receive appropriate education and training in the
2869    areas of anatomy, physics, technique and principles of radiograph! c exposure, radiation
2870    protection, radiographic positioning, and image processing that are relevant to dental imaging.
2871    Proficiency can be demonstrated by satisfying existing state certification programs for dental
2872    auxiliaries.  Also, proficiency can be improved by reviewing dental radiology practice
2873    recommendations from the American Dental Association.
2875    Operators of dental x-ray equipment may be exposed to primary radiation in the  useful beam,
2876    leakage radiation from the tube housing, and scattered radiation.  Operator protection measures
2877    are required to minimize their occupational exposure.  There are three basic methods to reduce
2878    the occupational dose from x-rays: position, distance, and  shielding. The  most effective way of
2879    reducing operator exposure to primary radiation is to enforce  strict application of the position
2880    and distance rule (i.e., the operator should stand at least 2  m (6 ft) away from the tube head of
2881    the dental x-ray generator).  If the operator cannot stand at least this far from the patient during
2882    the exposure, he or she should stand behind an appropriate barrier or outside the  operatory
2883    behind a wall.  In clinics or field situations, where the operator is required to be in the immediate
2884    exposure area,  the operator should be positioned at the location of minimum exposure.  This
2885    location, also known as the safe quadrant, is at an angle between 90 and 135° to the primary
2886    beam.  Dental personnel should not hold image receptors in patients' mouths.  If a patient has to
2887    be restrained during exposure, a relative or friend of the patient should do so. The relative or
2888    friend may be provided a lead apron and latex gloves if the image receptor is to be held in the
2889    mouth  so they have protection during exposure.
2891    In panoramic imaging, scattered radiation is typically low  due to the narrow beam of radiation
2892    and the shielding incorporated into the cassette carrier. With  a typical workload, operators can
2893    produce panoramic images without the use of shielding as long as they are at least 2 meters (6
2894    feet) from the unit.  An appropriate shield should be used if this distance cannot be maintained.
2896    Structural shielding criteria are provided by NCRP (NCRP 2003).  Only a qualified individual
2897    (preferably  a qualified physicist) can determine how much shielding is needed for a given
2898    situation. The walls of the dental x-ray operatory must provide sufficient  attenuation to limit the
2899    exposure of other individuals to permissible levels.  Usually, it is not necessary to line the walls
2900    with lead to meet this requirement when intraoral or panoramic equipment is used. A wall
2901    constructed of gypsum wall board (drywall) has been determined to be sufficient for use of this
2902    equipment in the average dental office (MacDonald et al. 1983).

                                         DRAFT PROPOSAL

2904    Any individual who is likely to exceed a designated fraction of the regulatory dose limit shall be
2905    enrolled in a radiation monitoring program (OSHA 2012; USNRC 2012c).  Historically, dental
2906    radiation workers have not approached these limits and have not required dosimetry when good
2907    radiation practices have been used.  To determine if dosimeters are required, evaluations of
2908    occupational dose should be conducted by a qualified physicist when a program is initiated,
2909    facilities are significantly modified, or equipment or processes change. The evaluation may
2910    consist, for example, of monitoring personnel for a period of time or assessing the radiation field
2911    around the equipment. With regard to workers who have declared their pregnancy, NCRP
2912    Report No. 145 states that "Personal dosimeters shall be provided for known pregnant
2913    occupationally-exposed personnel" (NCRP 2003).
2915          Procedures
2917    Justification applies to imaging in dentistry.  The number of images obtained should be the
2918    minimum necessary to obtain essential diagnostic information. Dental radiographs should be
2919    prescribed only following an evaluation of the patient's needs that includes a health history
2920    review, a clinical dental history assessment, a clinical examination and an evaluation of
2921    susceptibility to dental diseases. A full mouth survey or panoramic radiograph of the teeth and
2922    jaw structure may be justified for forensic purposes for military personnel.  Postoperative
2923    radiographs should be taken only when there is clinical indication and not as verification for
2924    third-party payment plans. This is consistent with the recommendations of the Food and Drug
2925    Administration and the American Dental  Association (ADA FDA 2004; NCRP 1990).  In cases
2926    where emerging new dental imaging technologies are used by physicians for non-dental
2927    evaluations, these physicians should request these  studies through their medical imaging ordering
2928    procedures as determined by their local facility.
2930    Optimization also applies to imaging in dentistry.  In order to  achieve lower exposures, the
2931    operator's manual should be readily available to the user, and  the equipment should be operated
2932    following the manufacturer's instructions, including any appropriate adjustments for optimizing
2933    dose and ensuring adequate image  quality. The x-ray machine should be operated at the highest
2934    kilovoltage (kVp) adequate for diagnosis. An image receptor  holding device should be used for
2935    proper film, photostimulable phosphor (PSP) plates, or sensor positioning whenever possible.
2936    Technique charts provided by manufacturers should be reviewed for proper image receptor
2937    placement.  Protocols may be relaxed in the cases where anatomy or the inability of the patient to
2938    cooperate makes beam-receptor alignment awkward.
2940    Cone beam computed tomography (CBCT) is used for dental implant planning, orthodontics,
2941    surgical assessment of pathology, pre- and postoperative assessment of craniofacial fractures,
2942    and temporomandibular joint assessment. CBCT provides high-resolution computed
2943    tomographic images with short scanning times  (approximately 20 seconds) and high geometric
2944    accuracy (actual size of item imaged without distortion) (Scarfe et al. 2006). The major
2945    advantage of CBCT over multi-row detector computed tomography systems (MDCT) is the
2946    lower radiation dose . CBCT scanners utilize a narrow, collimated cone beam of radiation that
2947    scans both the maxilla and mandible at one time. The effective dose of a CBCT examination is
2948    approximately 7 times greater than a panoramic image but only 2-5%  of a conventional CT of
2949    the same region (Scarfe et al. 2006). Given these low radiation doses, the same radiation


                                      DRAFT PROPOSAL

2950   protection guidelines recommended for conventional dental imaging should be implemented for
2951   CBCT.

                                          DRAFT PROPOSAL

2955    Diagnostic radiology is an essential part of present-day veterinary practice.  The typical imaging
2956    workload in a veterinary practice is low on the average; however, certain practices unique to
2957    veterinary radiology can expose the staff at a greater rate than typical operators. In veterinary
2958    medicine, the possibility that anyone may be exposed to enough radiation to create deterministic
2959    effect is extremely remote.
2961    There are two main aspects of the problem to be considered.  First, personnel working with x-ray
2962    imaging equipment should be protected from excessive exposure to radiation during their work.
2963    Secondly, personnel in the vicinity of veterinary radiology facilities and the general public
2964    require adequate protection (NCRP 2004b; OSHA 2012; USNRC 2012c).
2966           Equipment
2968    The recommendations pertaining to the use of medical radiographic equipment and shielding
2969    requirements for humans apply to the use of similar equipment in veterinary medicine.  The
2970    following points are highlighted for veterinary applications:
2972     1.   In a fixed facility, the floors, walls, ceilings and doors should be built with materials
2973         providing adequate radiation protection to workers.
2974     2.   The shielding should be constructed to form an unbroken barrier.
2975     3.   In a fixed facility, a control booth should be provided for the protection of the operator.
2976         Mobile protective barriers are not considered adequate as a control booth except for
2977         facilities requiring no shielding at 1 meter from source,  or where 1/20 of permissible dose
2978         equivalent limits are not likely to be exceeded at 1 meter.
2979     4.   The control booth should be located, whenever possible, such that the radiation has to be
2980         scattered at least twice before entering  the booth. In facilities where the radiation beam
2981         may be directed toward the booth, the booth becomes a primary barrier and should be
2982         shielded accordingly.
2983     5.   The control booth should be positioned so that during an irradiation no one can enter the
2984         radiographic room without the knowledge of the operator.
2985     6.   Required warning signs should be posted on all entrance doors of each x-ray  imaging room.
2986     7.   Mobile x-ray equipment used routinely in  one location is considered to be a fixed
2987         installation, and the facility should be shielded accordingly.
2988     8.   Protective aprons, gloves and thyroid shields used for veterinary x-ray examinations should
2989         provide attenuation equivalent to at least 0.5 mm of lead-equivalence at x-ray tube voltages
2990         of up to 150 kVp. Protection should be provided throughout the glove, including  fingers
2991         and wrist. Further discussion is provided in the section on RADIATION SAFETY
2995    An addition to the diagnostic veterinary imaging inventory as of 2012 is hand-held, battery-
2996    powered x-ray systems which have been developed for radiographic imaging. The hand-held
2997    exposure device is activated by a trigger in the handle of the device by the operator. This
2998    technology, at first glance, poses several concerns, which appear inconsistent with previously


                                         DRAFT PROPOSAL

2999    established radiological protection guidelines. The first concern is that the x-ray tube assembly
3000    is hand-held by the operator rather than wall mounted. The second concern is that the trigger for
3001    x-ray exposure is within the hand-held device and not remotely located away from the source of
3002    radiation. The final concern is that the operator does not stand behind a barrier. These concerns
3003    arise from previous guidelines that were established to: 1) protect the operator from possible
3004    radiation leakage from the housing of the device; 2) protect the operator from backscatter from
3005    the patient; and 3) protect the  patient from excessive radiation or repeat exposures when
3006    inadequate image quality results from movement of the hand-held x-ray generator.
3008    For additional information, see the veterinary section below on SPECIAL PROCEDURES FOR
3011          Testing and Quality Assurance
3013    Since veterinary equipment is generally identical to medical equipment all the quality assurance
3014    tasks associated with medical  equipment can be applied to veterinary equipment; however, based
3015    on the typical workload a reduced quality assurance program is probably warranted in most
3016    cases.  Atypical testing and QA program would consist of at least the following:
3017     1.  It is essential that a radiation safety survey be completed on all new veterinary x-ray
3018        equipment by or under the direction of a qualified expert. As stated in NCRP Report No.
3019        148, "Resurveys shall be made following replacement of irradiation equipment, or
3020        modifications that could change the radiation source, whenever the workload increases
3 021        significantly, or if other operating conditions are modified that could affect the radiation
3022        dose in occupied areas. Resurveys are required after the installation of supplementary
3023        shielding to determine the adequacy of the modification" (NCRP 2004b).
3024     2.  Prior to the first use of a mobile fluoroscope, a radiation exposure survey should be done
3025        with the x-ray beam and maximum operating potential and with an appropriate test
3026        phantom in place to determine the perimeter of the area within which individuals without
3027        radiation protection apparel should not be present (NCRP 2004b).
3028     3.  Reduce radiation exposure to the  animal patient, operator, and members of the public by
3029        minimizing the need for  repeat exposures because of inadequate image quality (NCRP
3030        2004b).
3031     4.  For film-based systems,  a sensitometry and densitometry test should be done each day the
3032        system is used in order to ensure consistent operation. A step wedge test may be used as a
3033        substitute for the standard sensitometry and densitometry test.
3034     5.  Darkroom fog or darkroom integrity should be evaluated biannually. This may be
3035        especially relevant if the darkroom is not a single use room.
3036     6.  It is strongly recommended that lead personnel protective equipment (e.g., aprons, gloves,
3037        thyroid collars) be evaluated at least annually for lead protection integrity using visual and
3038        manual inspection (Miller et al. 2010b; NCRP 2010).  If a defect in the attenuating material
3039        is suspected, radiographic or fluoroscopic inspection may be  performed as an alternative to
3040        immediately removing the item from service. Consideration  should be given to minimizing
3041        the radiation exposure of inspectors by minimizing unnecessary fluoroscopy.

                                          DRAFT PROPOSAL

3044           Personnel
3046    Veterinary x-ray equipment operators, similar to medical x-ray equipment operators, should
3047    receive appropriate education and training in the areas of anatomy, physics, technique and
3048    principles of radiograph! c exposure, radiation  safety, radiographic positioning, and image
3049    processing that are relevant to veterinary imaging. Only personnel with specific, appropriate
3050    training should be permitted to operate x-ray equipment. It is strongly recommended that the
3051    veterinary medical application of x-ray equipment be performed only by or under the general
3052    supervision of a veterinarian properly trained and credentialed to operate such equipment.
3053    Individuals who routinely use veterinary radiologic equipment need a basic understanding of the
3054    following:
3056     1.   animal positioning techniques to allow for minimal radiation exposure for employees;
3057     2.   basic principles and concepts of radiation in general and x-radiation in particular;
3058     3.   component parts/workings of the x-ray machine and the production of x-rays;
3059     4.   factors affecting the quality of the x-ray beam and the radiographic image;
3060     5.   effects of ionizing radiation on living tissues;
3061     6.   radiation bioeffects, health, and safety;
3062     7.   radiation protection procedures for the operator and the patient;
3063     8.   selection of appropriate imaging surveys, image receptor types, duplicating, and record
3064         keeping;
3065     9.   technique of proper image processing, handling, and record keeping;
3066     10. viewing  techniques and principles of interpretation;
3067     11. digital imaging and alternate imaging modalities;
3068     12. appearances  of normal radiographic landmarks, artifacts, and shadows; and
3069     13. requirements for monitoring and documenting staff occupational radiation exposure.
3071           Procedures
3073    The procedures pertaining to the use of veterinary radiography are generally equivalent to
3074    procedures for medical (human) radiography.  The following recommendations will minimize
3075    the  dose to veterinary facility staff and clients  from veterinary diagnostic radiographic
3076    procedures. All suggestions will secondarily minimize the dose to the radiation operator and
3077    consequently, the  results may be considered as a double benefit to the patient and the worker.
3078    The guidelines and procedures outlined in this section are primarily directed toward occupational
3079    health protection.  Adherence to these guidelines will also provide protection to visitors and
3080    other individuals in the vicinity of an x-ray facility. However, the safe work practices and
3081    procedures for using various types of x-ray equipment should be regarded as a minimum to be
3082    augmented with additional requirements, when warranted, to cover special circumstances in
3083    particular facilities.  To achieve optimum safety, operators should make every reasonable effort
3084    to keep exposures to themselves and to other personnel as low as reasonably achievable.

3086                 Veterinary clinic setup
3088     1.   An x-ray room should be used for only one x-ray procedure at a time.


                                          DRAFT PROPOSAL

3089     2.   All entrance doors to an x-ray room should be kept closed while a radiographic procedure is
3090         being performed.
3091     3.   Where a control booth or protective barrier is available, it is strongly recommended that
3092         operators remain inside or behind when making an irradiation. If a control booth or
3093         protective screen is not available, the operator should always wear protective clothing.
3094     4.   When film screen imaging is used, the fastest combination of films and intensifying screens
3095         consistent with diagnostically acceptable results and within the capability of the equipment
3096         should be used.
3097     5.   When digital x-ray imaging is used, procedures should be established to prevent
3098         excessively high doses, also known as dose creep, as addressed in the radiography section
3099         of this document.
3101                 Personal protective equipment
3103     1.   Personnel should use protective devices, as appropriate.
3104     2.   Protective aprons, gloves and thyroid  shields should be hung or laid flat and never folded,
3105         and manufacturer's instructions should be followed.
3106     3.   Armored gloves (welding gloves) should be used to restrain fractious animals.  Since lead-
3107         lined gloves will not protect against bites that could puncture the lead, the radiation
3108         protection provided by the garment may be compromised (NCRP 2004b).
3110                 Animal restraint
3112     1.   If necessary, the animal should be sedated or holding devices used during radiography.
3113         However, if this is not possible and a person must restrain the animal, that person should
3114         wear appropriate radiation protective equipment (aprons, gloves, etc.) and avoid direct
3115         irradiation by the primary x-ray beam. No person should routinely hold animal patients
3116         during x-ray examinations (NCRP 2004b).
3117     2.   Individuals under the age of 18 and pregnant or potentially pregnant women should not be
3118         permitted to hold animals during radiography.
3120                 Use of x-ray equipment
3122     1.   X-ray equipment should be operated only by or under the direct supervision of qualified
3123         individuals.
3124     2.   X-ray machines that are energized and ready to produce radiation should be supervised.
3125     3.   The x-ray room should contain only those persons whose presence is essential when a
3126         radiological procedure is carried out.
3127     4.   The radiation beam should always be  directed toward adequately shielded or unoccupied
3128         areas.
3129     5.   The radiation beam and scattered radiation should be attenuated as closely as possible to the
3130         source.
3131     6.   Personnel should keep as far away from the x-ray beam as is practicable at all times (2 m).
3132         Exposure of personnel to the x-ray beam should never be allowed unless the beam is
3133         adequately attenuated by the animal and by protective clothing or barriers.
3134     7.   A hand-held radiographic cassette or image receptor should not be used.


                                         DRAFT PROPOSAL

3135     8.   For table-top radiography when the sides of the table are not shielded, a sheet of lead at
3136         least 1 mm in thickness and slightly larger than the maximum beam size should be placed
3137         immediately beneath the cassette or film.
3138     9.   Veterinarians should not allow veterinary diagnostic radiation devices under their control to
3139         be used on human beings (NCRP 2004b).
3140     10. Technique charts should be developed for all animal types that are routinely radiographed.
3142                 Personal dosimetry
3144     1.   The workload in a typical veterinary clinic may not be sufficient to require the issuance of
3145         personal dosimetry; however, a qualified expert should be consulted for a  clinic's particular
3146         situation.
3147     2.   Personal dosimetry should be worn in a manner that complies with regulatory requirements
3148         and ensures that radiation doses can be determined accurately. See the section on
3150     3.   Occupational radiation dose limits in veterinary and human medical practice should be the
3151         same.  See the section on PERSONNEL AND AREA MONITORING.
3153                 Special procedures for portable hand-held systems
3155      1.  Portable hand-held x-ray systems should be used as outlined in the instructions that come
3156         with the unit. Exposures using this unit should be made only when the area adjacent to the
3157         clinical area is free of all individuals not directly involved in the imaging procedure. When
3158         standard radiology protocols are utilized according to manufacturer instructions, with the
3159         ring shield in place, there is no indication for additional radiation protection
3160         recommendations.
3162      2.  Portable hand-held x-ray systems use essentially the same amount of radiation as
3163         traditional wall mounted x-ray units since the amount of radiation needed  to generate an
3164         adequate image is determined by the image receptor, not by the x-ray device. Radiation
3165         safety criteria for operators of the hand-held device should be the same as mentioned
3166         earlier for conventional exposure systems.
3168      3. All operators of these units should be instructed on its proper storage. Due to the portable
3169         nature of the hand-held device, it should be secured properly when not in use to prevent
3170         accidental damage, theft or operation by an unauthorized user. Hand held units should be
3171         stored in locked cabinets, locked storage rooms or locked work areas when not under the
3172         direct supervision of an individual authorized to use them.  Units with user-removable
3173         batteries should be stored with the batteries removed.  Records listing the  names of
3174         approved individuals that are granted access and use privileges should be prepared and kept
3175         current (quarterly revi ew).

                                         DRAFT PROPOSAL

3177                            MEDICAL IMAGING INFORMATICS
3179    Digital information systems are used for the ordering, scheduling, tracking, processing, storage,
3180    transmission, and viewing of imaging studies and providing the reports of study interpretations.
3181    These systems should be used to the greatest extent possible. They include picture archiving and
3182    communication systems (PACSs), teleradiology systems, radiology information systems,
3183    hospital information systems, and the Electronic Health Record (Congress 2007). For efficiency
3184    of workflow, these systems do not operate independently, but instead are connected to the
3185    imaging devices and each other by computer networks and exchange information in accordance
3186    with standards such as TCP/IP (Transmission Control Protocol/Internet Protocol, or the Internet
3187    protocol suite), DICOM, HL7, and ME. These information systems are complex and will not be
3188    discussed in detail in this report.  However, there are certain aspects of these systems that
3189    indirectly can affect the radiation doses to patients from imaging studies. Proper planning,
3190    design, management, and use of these systems can help avoid performing unnecessary or
3191    inappropriate studies and repeat studies. These systems can also help in monitoring doses to
3192    patients and image receptors and  monitoring retakes; the information from this monitoring can
3193    help in optimizing doses from imaging procedures.
3195    These information systems can help avoid the ordering of unnecessary or inappropriate imaging
3196    studies. At the time that a Referring Medical Practitioner places the order for an imaging study,
3197    the system can provide decision support regarding the appropriateness of the study for the
3198    particular patient and notification of alternatives that may impart less or no radiation. These
3199    information systems can also notify the Referring Medical Practitioner of previously acquired
3200    studies that may render an additional imaging study unnecessary.
3202    The inability to retrieve an imaging study can create the need for a repeat study. These digital
3203    information systems and procedures for their use should be designed to protect against data loss.
3204    Such measures should include administrative, physical, and technical safeguards, including
3205    storing information on stable media, ensuring the storage location is secure from natural and
3206    human threats, ensuring the stored information is secure from deliberate or accidental erasure or
3207    modification, storing duplicate backup copies of the information on media in a remote location
3208    or locations, and precautions against loss of information from media wear and aging and media
3209    obsolescence.  Additionally, the facility should have a disaster plan in place to guide operations
3210    when the network is inoperable or power outage affects operation of the PACS system. It is the
3211    responsibility of the institution to meet the records retention, security, privacy, and retrieval
3212    requirements of its agency and other Federal requirements (e.g., HIPAA and associated Federal
3213    regulations) (ACR 2007c; ACR 2009a; DHHS 2012b), and to address the aforementioned issues.
3215    These systems also provide an important quality assurance  function. They should facilitate
3216    monitoring of patient dose indices, the doses to radiographic image receptors, and the
3217    number of retakes and inadequate images. This requires both capture and storage of this
3218    information and appropriate software tools for data analysis and display. Equipment
3219    manufacturers should be encouraged to work with professional societies and standards
3220    organizations to develop and implement standardized dose  reporting systems. These
3221    systems should provide an estimate of patient radiation dose that is accurate for the
3222    individual, available in real time to the operator, and documented for the individual


                                        DRAFT PROPOSAL
3223   patient. These systems should also be capable of transmitting de-identified patient
3224   radiation dose data to a central dose registry. To this end, Federal facilities should give
3225   preference to equipment with these standardized dose reporting systems when making
3226   purchasing decisions.

                                          DRAFT PROPOSAL

3230    GENERAL
3232     1.   Each facility should establish a formal mechanism whereby Referring Medical Practitioners
3233         have sources of information available at the time of ordering regarding appropriate
3234         diagnostic imaging methods to answer the clinical question and to optimize ionizing
3235         radiation dose to the patient.  These may include decision support software or
3236         appropriateness criteria. A mechanism for consultation with Radiological Medical
3237         Practitioners should also be made available.
3238     2.   The Universal Protocol should always be followed to ensure the right patient gets the right
3239         procedure.
3240     3.   Physicians and staff should always strive to limit patient irradiation to that necessary to
3 241         perform the procedure.
3242     4.   Facilities involved in health care delivery should ensure that operators of medical imaging
3243         equipment that use x-rays: 1) are adequately trained to produce acceptable quality  images,
3244         2) know how to produce these images with appropriate patient doses, and 3) periodically
3245         demonstrate continuing competence.
3246     5.   Facilities should ensure that the operator's manual is readily available to the user, and the
3247         equipment is operated following the manufacturer's instructions, including any appropriate
3248         adjustments for optimizing dose and ensuring adequate image quality.
3249     6.   Facilities should establish a formal mechanism whereby Radiological Medical Practitioners
3250         are available to consult with Referring Medical Practitioners regarding the optimal
3251         diagnostic imaging method to answer the clinical question while minimizing ionizing
3252         radiation dose to the patient.
3253     7.   Facilities should use equipment that provides relevant patient dose information.  This
3254         equipment should allow the facility to program in dose  alerts to inform operators if selected
3255         operating parameters might produce a radiation dose exceeding that recommended by  the
3256         facility.
3257     8.   Facilities should use the dose information from individual patient imaging procedures that
3258         is provided by imaging equipment as part of the quality assurance program for identifying
3259         opportunities to reduce dose.  .
3260     9.   Facilities should use reference levels as a quality improvement tool by collecting and
3261         assessing radiation dose data. Each facility should also submit its radiation dose data to a
3262         national registry, if and when such a registry is available.
3263     10. Facilities should be aware  of upgrades to software and hardware of x-ray imaging systems
3264         that enhance safety. These should be  evaluated and considered for implementation.
3265     11. Facilities should assess the radiation exposure of workers and provide periodic feedback to
3266         them.  In addition, each worker who is expected to receive  more than 10% of the applicable
3267         dose limit should be required to wear one or more dosimeters.
3271     1.  Facilities should establish a range of acceptable precision performance and ensure each
3272        technologist is trained and meets this standard.

                                          DRAFT PROPOSAL

3273     2.  The facility should ensure that patients imaged for precision and cross-calibration studies
3274        should be representative of the facility's patient population
3275     3.  Facilities should ensure that practitioners who interpret bone densitometry results are
3276        knowldegable in this field and not rely solely on a report produced by the equipment..
3280     1.  Facilities should ensure that when a monitored radiation worker declares her pregnancy she
3281        wears a dosimeter on the lower abdomen, underneath the apron at the level of the fetus.
3282        The dosimeter should be exchanged monthly. She should be issued this dosimeter unless
3283        such a dosimeter is already  being worn.
3284     2.  Children are more radiosensitive than adults.  Facilities should ensure that technique and
3285        imaging protocols are appropriate for the child's size or weight to ensure adequate image
3286        quality and optimize radiation dose.
3287     3.  In general, facilities should ensure that neither screening nor elective x-ray examinations
3288        are performed on pregnant women.
3291     1.  Facilities should ensure that beam indicating devices are used with sensors,  specific and
3292        ongoing training is given to orient operators on ways to eliminate the need for retakes, and
3293        technique charts provided by manufacturers are reviewed periodically for proper sensor
3294        placement.
3295     2.  In clinics or field use environments where film may  still need to be used, the fastest and
3296        most appropriate film should be used.
3297     3.  In facilities where panoramic and other extraoral projections are obtained using film, it is
3298        recommended that high speed film be used and spectrally  matched to its appropriate rare
3299        earth intensifying screen.
3300     4.  An image receptor holding  device for proper film, PSP or sensor positioning should be used
3301        whenever possible.
3302     5.  Thyroid shielding shall be provided for children, and should be provided for adults, when it
3303        will not interfere with the examination (NCRP 2003).
3304     6.  Dental clinics that use film  should evaluate film processing darkrooms and daylight loaders
3305        for light leaks and safelight performance.
3308     1.  The facility's procedures should be written with the understanding that fluoroscopy can
3309        deliver a significant radiation dose to the patient, even when used properly.
3310     2.  The facility  should ensure that every person who operates or directs the operation of
3311        fluoroscopic equipment is trained in the safe use of the equipment.
3312     3.  When a facility purchases fluoroscopic equipment, the additional cost of including dose-
3313        reduction technology is justified because the reduction in patient radiation dose can be
3314        considerable.
3315     4.  Some types  of fluoroscopic procedures have a potential for patient skin doses exceeding 2
3316        Gy. The facility should ensure that there are additional training requirements for operators
3317        and additional equipment requirements for these procedures.

                                          DRAFT PROPOSAL

3318     5.  The facility should ensure that patient radiation dose data, including patient skin dose data
3319         when available, are recorded in the patient's medical record.
3323     1.  Facilities should ensure that the veterinary medical application of x-ray equipment is
3324         performed only by or under the general supervision of a veterinarian properly trained and
3325         credentialed to operate such equipment.
3326     2.  Facilities should ensure that individuals who routinely use veterinary radiographic
3327         equipment have a basic understanding of using medical x-rays and animal positioning
3328         techniques.
3329     3.  Facilities should ensure that armored gloves (welding gloves) are used to restrain fractious
3330         animals since lead-lined gloves will not protect against bites that could puncture the lead.
3331     4.  Facilities should have animal sedatives and holding devices available, and ensure they are
3332         used, if necessary.
3333     5.  Facilities should not allow anyone to routinely hold animal patients during x-ray
3334         examinations.
3335     6.  Facilities should not allow veterinary diagnostic radiation devices under their control to be
3336         used on human beings.
3340     1.  Patient safety requires that infrastructure exists for collecting, storing, and analyzing patient
3341         dosimetry data. Facilities should plan for longitudinal tracking of patient radiation doses.
3342         This planning should address the data acquisition, networking, storage, analysis, and
3343         security requirements of existing and planned future diagnostic devices.
3344     2.  Digital information systems should be used in Federal facilities to the greatest extent
3345         possible.
3346     3.  Facilities should give preference to equipment with standardized dose reporting systems
3347         when making purchasing decisions.
3348     4.  Facilities should ensure that their health professionals use digital information systems, to
3349         help avoid the ordering of unnecessary or inappropriate imaging studies.
3353         Federal facilities should ensure that, except in emergency situations, informed consent is
3354         obtained from the patient or the patient's legal representative and is appropriately
3355         documented prior to the initiation of any procedure that is likely to expose the patient, or
3356         fetus if the patient is pregnant, to significant risks and potential complications.
3360         Facilities should ensure that appropriate information is obtained and reviewed at the time of
3361         ordering/prescribing to optimize the choice of study and protocol, and to optimize the dose.

                                          DRAFT PROPOSAL

3365     1.   Reference levels are dose values for a standard phantom or actual patient for specific
3366         procedures measured at a number of representative clinical facilities.  Facilities should use
3367         reference levels as quality assurance and quality improvement tools.
3368     2.   National reference levels that are specific for the U.S. population should continue to be
3369         developed.  The on-going nationwide collection of these data from government and non-
3370         government facilities, such as by NEXT and ACR, is essential to this effort. Facilities
3371         should submit radiation dose data to a national registry, if and when available.
3372     3.   Facilities should ensure that a representative sampling and assessment of exposure
3373         indicators from each modality is performed at least annually, but preferably quarterly. It
3374         should be reviewed by the chief technologist.  This effort should be performed under the
3375         guidance of a qualified physicist.
3376     4.   If the mean radiation dose at the facility exceeds the reference level, the facility should
3377         investigate as appropriate to reduce radiation dose. If the mean radiation dose is
3378         significantly lower than the reference level, the facility should evaluate image quality.
3379     5.   If local practice at a facility results in a  mean radiation dose that is greater than the  RL, the
3380         facility should investigate the equipment. If the equipment is functioning properly  and
3381         within specification, operator technique and procedure protocols should be examined.



American Association of Physicists in Medicine
American College of Cardiology
American College of Cardiology Foundation
Accreditation Council for Graduate Medical Education
American College of Radiology
American Cancer Society
American Dental Association
automatic exposure control
American Heart Association
as low as reasonably achievable
American Medical Association
American National Standards Institute
American Osteopathic Association
American Osteopathic Board of Radiology
American Registry of Radiologic Technologists
Agency for Toxic Substances and Disease Registry
Biological Effects of Ionizing Radiation
beam indicating device
bone mineral density
cone beam computed tomography (cone beam CT)
Code of Federal Regulations
Cardiovascular and Interventional Radiology  Society of Europe
Certified Nuclear Medicine Technologist
computed radiography
Conference of Radiological Control Program  Directors
computed tomography
computed tomography dose index
volumetric CTDI
dose area product (units are Gy-cm2)
direct current
Doctor of Dental Medicine
Direct digital radiography
Doctor of Dental Surgery
see DXA
Department of Health and Human Services
dose length product
Department of Defense
digital radiography
Diagnostic Radiologic Technologist
dual-energy x-ray absorptiometry (formerly DEXA)
Electronic Health Record
Environmental Protection Agency
entrance skin exposure



entrance skin exposure guide
Food and Drug Administration
Federal Guidance Report
field of view
genetically significant dose
gray (radiation dose, equal to 100 rem). Subunitis mGy (milligray)
Heart Rhythm Society
International Commission on Radiological Protection
International Electrotechnical Commission
Institutional Review Board
International Society for Clinical Densitometry
Interagency Steering Committee on Radiation Standards
kerma  area product
kinetic energy released in matter (type of radiation measurement in air)
kilovolts potential (or kilovolts peak)
multi-row detector computed tomography (multi-detector CT)
Mammography Quality Standards Act
millisi evert
National Cancer Institute
National Council on Radiation Protection and Measurements
Nationwide Evaluation of X-ray Trends
National Institutes of Health
Occupational Safety and Health Administration
optically stimulated luminescence
picture archiving and communication system
positron emission tomography
position-sensitive x-ray detection
photostimulable phosphor
Registered Cardiovascular Invasive Specialists
Traditional radiation unit for equivalent dose (product of absorbed dose [rad] and
radiation weighting  factor). Subunit is mrem (millirem) or jirem (microrem)
Radiation  Safety Officer
Radiological Technologist Nuclear qualification
Society for Cardiac  Angiography and Intervention
single particle emission computed tomography
Society of Interventional Radiology
source-to-skin distance
sievert (SI radiation unit for equivalent dose or effective dose). Subunit is mSv
(millisievert) or jiSv (micro si evert)

3475   TLD         thermoluminescent dosimeter
3476   USPSTF     United States Preventive Services Task Force
3477   USN         United States Navy
3478   VA          US Department of Veterans Affairs

3480                                         GLOSSARY
3482    Acceptance test - a test carried out after new equipment has been installed or major
3483      modifications have been made to existing equipment, in order to verify compliance with the
3484      manufacturer's specifications, contractual specifications, and applicable local regulations or
3485      equipment standards
3486    Adequate image - an image that provides the information needed to answer the clinical question
3487      at an optimized dose, i.e., the lowest dose possible to produce that image
3488    Adequate image quality - image quality sufficient for the clinical purpose. Whether the image
3489      quality is adequate depends on the modality being used and the clinical question being asked.
3490    ALARA (as low as reasonably achievable) - a principle of radiation protection philosophy that
3491      requires that exposures to ionizing radiation be kept as low as reasonably achievable,
3492      economic and social factors being taken into account.  The protection from radiation exposure
3493      is ALARA when the expenditure of further resources would be unwarranted by the reduction
3494      in exposure that would be achieved.
3495    Ancillary personnel - personnel beyond the operational medical staff who provide support
3496      services
3497    Angiography - radiography of vessels  after the inj ection of a radiopaque contrast material;
3498      usually requires percutaneous insertion of a radiopaque catheter and positioning under
3499      fluoroscopic control (Stedman 2006)
3500    Attenuation - reduction in radiation intensity, such as via the use of shielding
3501    Backscatter (as opposed to  scatter) - a  Compton scattering event in which a photon strikes an
3502      object and deflects at an angle greater than 90°, i.e., in a direction back toward its source
3503    Beam indicating device (BID) - a lead lined tube attached to an x-ray tube head through which
3504      the primary x-ray beam will travel, used by the operator, especially in a dental setting, to align
3505      the b earn with the i mage re ceptor
3506    Benefit - the probability or quantifiable likelihood that health will improve or deterioration will
3507      be prevented as a result of performing or not performing a medical procedure
3508    Benefitrisk ratio -  a determination (possibly subjective) of the benefit to the patient from
3509      undergoing a procedure involving imaging using ionizing radiation compared with the risk to
3510      the patient from receiving a radiation dose associated with the consequent imaging.
3511      Maximizing the benefitrisk ratio involves balancing the benefitrisk ratio to the patient from
3512      an x-ray procedure against that from alternatives (e.g.,  ultrasound, MRI, or  no action).
3513    Bone densitometry  - the noninvasive measurement of certain physical characteristics of bone
3514      that reflect bone strength (typically reported as bone mineral content or bone mineral density)
3515      and used for diagnosing  osteoporosis, estimating fracture risk, and monitoring changes in
3516      bone mineral content
3517    Collimator - a device used to reduce the cross-sectional area of the useful beam of photons or
3518      electrons with an absorbing material
3519    Computed radiography (CR; also see DR) - a projection x-ray imaging method in which a
3520      cassette houses a sensor plate rather than photographic film. This photo-stimulable phosphor -
3521      coated plate captures a latent image when exposed to x-rays and, when processed, releases
3522      light that is converted to a digital image.
3523    Computed tomography (CT) - an imaging procedure that uses multiple x-ray transmission
3524      measurements and a computer program to generate tomographic images of the patient (NCRP
3525      2000)


3526    Cone - an open-ended device on a dental x-ray machine designed to indicate the direction of the
3527      central ray and to serve as a guide in establishing a desired source-to-image receptor distance
3528      (NCRP2000)
3529    Cone Beam Computed Tomography system (CBCT) - A digital volume tomography method
3530      used in some imaging applications using two dimensional digital detector arrays, and a cone-
3531      shape x-ray beam (instead of fan-shaped) that rotates around the patient to generate a high-
3532      resolution, 3D image, with high geometric accuracy. Reconstruction algorithms can be used
3533      to generate images of any desired plane.
3534    Credential - diploma, certificate, or other evidence of adequate educational performance that
3535      gives one a title or credit
3536    CTDIvoi - a radiation dose parameter derived from the CTDIW (weighted or average CTDI given
3537      across the field of view). The formula is:
3538      CTDUi = N-T-CTDIW /1, where
3539          N = number of simultaneous axial scans per x-ray source rotation,
3540          T = thickness of one axial scan (mm), and
3541          I = table increment per axial scan (mm).
3542    Deterministic effects - effects that occur in all individuals who receive greater than the threshold
3543      dose and for which the severity of the effect varies with the dose (NCRP 2003)
3544    Diagnosis - the determination of the nature of a disease, injury, or congenital defect (Stedman
3545      2006)
3546    Digital radiography (DR) - an x-ray imaging method (or radiography) which produces a digital
3 547      rather than film proj ection image. Includes both CR and DDR
3548    Direct digital radiography (DDR; also see CR and DR) - an x-ray imaging method in which a
3549      digital sensor, rather than photographic film, is used to capture an x-ray image. DDR is a
3550      cassette-less imaging method (providing faster acquisition time than cassette-based CR) using
3551      an electronic sensor that converts x-rays to electronic signals (charge or current) when
3552      exposed to x-rays.
3553    Dose - a measure of the energy deposited by radiation in a target. Used in this report as a
3554      generic term unless context refers to a specific quantity, such as  absorbed dose, committed
3555      equivalent dose, committed effective dose, effective dose, equivalent dose or organ dose, as
3556      indicated by the context.
3557          Cumulative air kerma  -  sum of the kinetic energy released  to a small volume of air at a
3558             specific point in space during a specified event or time frame when irradiation by an x-
3559             ray beam
3560          Cumulative dose - total radiation dose from all delivered to any specific organ or tissue
3561          Dose area product (DAP), also  called kerma-area product (KAP) - the product of the air
3562             kerma and the area  of the irradiated field and is measured in Gycm2, so it does not
3563             change with distance from the x-ray tube. A good measure of total energy delivered to
3 564             the patient, and of stochastic risk. Not a good indicator of deterministic risk
3565          Dose alert value - a value of CTDIvoi (in units of mGy) or of DLP (in units of mGycm)
3566             that is set by the operating institution to trigger an alert to the operator prior to
3567             scanning within an  ongoing examination if it would be exceeded by  an accumulated
3568             dose index, on acquisition of the next confirmed protocol element group.  An alert
3569             value represents a value above which the accumulated dose index value would be well
3570             above the institution's established range for the examination that warrants more
3571             stringent review and consideration before proceeding, (see dose notification value)


3572           Dose equivalent - the product of the absorbed dose at a point in the tissue or organ and
3 573             the appropriate quality factor for the type of radiation giving rise to the dose
3574           Dose length product (DLP) - an indicator of the integrated radiation dose from a
3575             complete CT examination. It addresses the total scan length by the formula DLP =
3576             CTDIvoi x scan length, with the units mGy-cm.
3577           Dose notification value - A value of CTDIvoi (in units of mGy) or of DLP (in units of
3578             mGycm) that is set by the operating institution to trigger a notification to the operator
3579             prior to scanning when exceeded by a  corresponding dose index value expected for the
3580             selected protocol element. A notification value represents a value above which a dose
3581             index value would be above the institution's established range for the protocol
3582             element, (see dose alert value)
3583           Dose registry - see registry
3584           Effective dose - (E) - the sum of the weighted equivalent doses for the radiosensitive
3585             tissues and organs of the body.  It is given by the expression E = ET (WT HT), in which
3586             HI is the equivalent dose in tissue or organ T and WT is the tissue weighting factor for
3587             tissue or organ T. The unit of E and HI is joule per kilogram (J kg"1), with the special
3588             name si evert (Sv) (see equivalent dose and tissue weighting factor).
3589           Equivalent dose (formerly dose equivalent) - (HT): the mean absorbed dose (DT) in a
3590             tissue or organ modified by the radiation weighting factor (WR) for the type and energy
3591             of the radiation.  The quantity HT,R, defined as HT,R = WR • DT,R, where DT,R is the
3592             absorbed dose  delivered by radiation type R averaged over a tissue or organ T and WR
3593             is the radiation weighting factor for radiation type R (IAEA 2011 a). The unit for HT is
3594             J kg"1, with the special name si evert (Sv).
3595           Reference point dose - radiation dose at the reference point, selected for reporting
3596             purposes, which is located at the center or in the central part of the planning target
3597             volume (PTV)
3598           Skin dose - radiation dose to the dermis
3599    Dosimeter -  dose measuring device (NCRP 2003)
3600    Electronic Health Record (EHR) - an electronic  record of health-related information on an
3601      individual that is created, gathered, managed,  and consulted by authorized health
3602      professionals and staff (Congress 2007)
3603    Exposure - in this report, exposure is used most  often in its general  sense, meaning to be
3604      irradiated. When used as the specifically defined radiation quantity, exposure is a measure of
3605      the ionization produced in air by x or gamma  radiation. The unit of exposure is coulomb per
3606      kilogram (C kg"1). The special unit for exposure is roentgen (R),  where 1 R = 2.58 x 10"4 C
3607      kg"1.
3608    Exposure categories-
3609      Medical exposure - exposure incurred by patients for the purpose of medical or dental
3610      diagnosis  or treatment; by carers and comforters associated with  medical, dental, and
3611      veterinary procedures; and by volunteers in a  program of biomedical research involving their
3612      exposure
3613      Occupational exposure - exposure of workers incurred in the course of their work
3614      Public exposure - exposure incurred by members of the public from sources in  planned
3615      exposure situations, emergency exposure situations, and existing exposure situations,
3616      including incidental medical exposure, but excluding any occupational or prescribed medical
3617      exposure


3618    Film/film radiograph - film is a thin, transparent sheet of polyester or similar material coated on
3619      one or both sides with an emulsion sensitive to radiation and light; a radiograph is a film or
3620      other record produced by the action of x-rays on a sensitized surface (NCRP 2003)
3621    Filtration - material in the useful beam that usually absorbs preferentially the less penetrating
3622      radiation (NCRP 2003)
3623    Fluoroscopy - the process of producing a real-time image using x-rays (NCRP 2003)
3624    Gamma ray - a photon emitted in the process of nuclear transition or radioactive decay
3625    Gray (Gy) - the special  SI name for the unit of the quantities absorbed dose and air kerma. 1 Gy
3626      = 1 J kg"1 (see rad, rem, gray, and Si evert)
3627    Guidance level - optimal range of detector exposure index values that should be based on patient
3628      body habitus, anatomical view, clinical question, and other relevant factors
3629    Health physics - the field of science concerned with radiation physics and radiation biology and
3630      their application to radiation protection. Health physicists may specialize in nuclear power,
3631      environmental and waste management, laws and regulations, dosimetry, emergency response,
3632      medicine  or a host of other sub-specialties where radiation is utilized.  Of particular interest
3633      for this  document is the medical health physics sub-specialty.
3634    Health physicist - a health professional, with education and specialist training in the concepts
3635      and techniques of applying physics in medical, environmental, or occupational settings, or
3636      competent to practice independently in one or more of the subfield specialties of medical
3637      physics or in health physics
3638    Health professional - an individual who has been formally recognized through appropriate
3639      national procedures to practice a  profession related to health (e.g., medicine, dentistry,
3640      chiropractic, podiatry, nursing, veterinary medicine) (adapted from (IAEA201 la))
3641    Helical - spiral in form; a curve traced on a cylinder (or human body) by the rotation of a point
3642      crossing its right section at a constant oblique angle
3643    Image - representation of an object  produced by machine-produced ionizing radiation
3644    Image receptor - a system for deriving a diagnostically usable image from the x-rays transmitted
3645      through the patient (NCRP 2003)
3646    Incidental  exposure - exposure not associated with the primary purpose for which it was
3647      delivered
3648    Informed consent - voluntary agreement given by a person or a patients' responsible proxy (e.g.,
3649      a parent) for participation in a study, immunization program, treatment regimen, invasive
3650      procedure, etc., after  being informed of the purpose, methods, procedures, benefits, and risks.
3651      The essential criteria of informed consent are that the subject has both knowledge and
3652      comprehension, that consent is freely given without duress or undue influence, and that the
3653      right  of withdrawal at any time is clearly communicated to the patient. Other aspects of
3654      informed  consent in the context of epidemiologic and biomedical research,  and criteria to be
3655      met in obtaining it, are specified in International Guidelines for Ethical Review of
3656      Epidemiologic Studies (Chanaud 2008;  Stedman 2006)(Geneva: CIOMS/WHO 1991) and
3657      International Ethical  Guidelines for Biomedical Research Involving Human Subjects (Geneva:
3658      CIOMS/WHO  1993).
3659    Intensifying  screen - a device consisting of fluorescent material, which is placed in contact with
3660      the film in a radiographic cassette. Radiation interacts with the fluorescent material, releasing
3661      light photons, (adapted from (NCRP 2003)

3662    Interlock - device that automatically shuts off or reduces the radiation emission rate from an
3663       accelerator to acceptable levels (e.g., by the opening of a door into a radiation area).  In
3664       certain applications, an interlock can be used to prevent entry into a treatment room.
3665    Intervention - any measure taken to alter the course of medical diagnosis whose purpose is to
3666       improve a health outcome
3667    Isocenter - the small point in space (or generally spherical or elliptical volume) where radiation
3668       beams emitted during the rotational swing of an x-ray tube gantry intersect
3669    Justification - the process of determining for a planned exposure situation whether a practice is,
3670       overall, beneficial, i.e. whether the expected benefits to individuals and to society from
3671       introducing or continuing the practice outweigh the harm (including radiation detriment)
3672       resulting from the practice (IAEA 2011 a)
3673    Kerma (kinetic energy released per unit mass, or kinetic energy released in matter) - the sum of
3674       the initial kinetic energies of all the charged particles liberated by uncharged particles (e.g., x-
3675       rays) in a material of mass 5m (IAEA 201 la). The unit for kerma is J kg-1, with the special
3676       name gray (Gy). Kerma can be quoted for any specified material at a point in free space or in
3677       an absorbing medium (e.g., air kerma).
3678    Kerma-area product (KAP, also called dose-area product or DAP) - the product of the air kerma
3679       and the area of the irradiated field and is measured in Gycm2, so it does not change with
3680       distance from the x-ray tube.  A good measure of total energy delivered to the patient, and of
3681       stochastic risk.  Not a good indicator of deterministic risk.
3682    Licensed independent practitioner - any individual permitted by law and by the organization to
3683       provide care and services, without direction or supervision,  within the scope of the
3684       individual's license and  consistent with individually granted clinical  privileges (see Referring
3685       Medical Practitioner and Radiological Medical Practitioner)
3686    Mammography - the use of x-rays to produce a diagnostic image of the breast
3687    Medical exposure - exposure incurred by patients for the purposes of medical or dental  diagnosis
3688       or treatment; by careres and comforters; and by volunteers subject to exposure as part of a
3689       program of biomedical research (IAEA 201 la)
3690    Medical health physics - the profession dedicated to the protection of healthcare providers,
3691       members of the public, and patients from unwarranted radiation exposure. Medical health
3692       physicists are knowledgeable in the principles of health physics and  in the applications of
3693       radiation in medicine. While medical physics and medical health physics have  a number of
3694       similarities and overlapping fields of study and interest, the emphasis of practice or day-to-
3695       day routines are different.
3696    Medical physics -  a field of science concerned with applying physics to medical imaging and
3697    determining patient dose. The Medical Physicist's clinical practice focuses on methods to assure
3698    the safe and effective delivery of radiation to achieve a diagnostic or therapeutic result as
3699    prescribed in patient care.
3700    Medical physicist - a health professional, with education and specialist training in the concepts
3701       and techniques of applying physics in medicine, competent to practice independently in one or
3702       more of the subfield specialties of medical physics (IAEA2011a)
3703    Medical technologist - a health professional, with specialist education and training in medical
3704       radiation technology,  competent to carry out radiological procedures, on delegation from the
3705       radiological medical practitioner, in one or more of the specialties of medical radiation
3706       technology (IAEA201 la)

3707    Members of the public - all persons who are not already considered occupationally exposed by a
3708      source or practice under consideration. When being irradiated as a result of medical care,
3709      patients are a separate category.
3710    Occupational  exposure - exposure to an individual that is incurred in the workplace as a result of
3711      situations that can reasonably be regarded as being the responsibility of management
3712      (exposures associated with medical diagnosis or treatment for the individual are excluded).
3713      (NCRP2003)
3714    Optically stimulated luminescent (OSL) dosimeter - a dosimeter containing a crystalline solid
3715      for measuring radiation dose, plus filters to help characterize the types of radiation
3716      encountered. When irradiated with intense light, OSL crystals that have been exposed to
3717      ionizing radiation give off light proportional  to the energy they receive from the radiation
3718      (NCRP2003).
3719    Optimal dose  - the minimum radiation dose required to be delivered by an x-ray imaging system
3720      to produce  an image that is of adequate quality for the intended purpose. This requires that
3721      the x-ray generator and imaging equipment to be working appropriately, (see adequate image).
3 722    Optimization  of protection - the process of determining what level of protection and safety
3723      would result in the magnitude of individual doses, the number of individuals (workers and
3724      members of the public) subject to exposure and the likelihood of exposure being "as low as
3725      reasonably achievable, economic and social factors being taken into account" (ALARA) (as
3726      required by the  System of Radiological Protection). For medical exposures of patients, the
3727      optimization of protection and safety is the management of the radiation dose to the patient
3728      commensurate with the medical purpose. "Optimization of protection and safety" means that
3729      optimization of protection and safety has been applied and the result of that process has been
3730      implemented. (IAEA 2011 a)
3731    Personal protective equipment - specialized clothing or equipment (e.g., leaded or tungsten
3732      apron, gloves, thyroid collar, eyeglasses) worn by an employee to protect against a hazard.
3733      General work clothes not intended to serve as a protection against a hazard are not considered
3734      to be personal protective equipment.
3735    Phantom - as  used in this report, a volume of tissue- or water-equivalent material used to
3736      simulate the absorption and scattering characteristics of the patient's body or portion thereof
3737    Picture archiving and communications system (PACS) - electronic system for the archival
3738      storage and transfer of information associated with x-ray images
3739    Pitch - in CT, table incrementation per x-ray tube rotation divided by  the nominal x-ray beam
3740      width at isocenter
3741    Prescribe - the process of requesting or ordering an exam to be performed, or the process of
3742      determining how an exam should be done in  order to optimize the choice of study and
3743      protocol, and optimize the radiation dose
3744    Protocol - selected parameters for image acquisition that defines the portion of the patient's
3745      anatomy to be imaged, whether and how contrast agents will be administered, the number and
3746      timing of imaging sequences, and acquisition technical parameters  (pitch, collimation or beam
3747      width, kV,  mA (constant or modulated and specifying the parameters determining the balance
3748      between image noise and patient dose), rotation time, physiologic gating, image quality
3749      factors, and reconstruction method
3750    Pulsed (as in pulsed fluoroscopy) - x-rays not produced continuously, but in rapid succession as
3751      pulses. Reduces dose by using a lower pulse rate (e.g., 15 or 7.5 pulses/sec) and in
3752      conjunction with digital image memory to  provide a continuous video display


3753    Qualified expert - an individual who, by virtue of certification by appropriate boards or societies,
3754      professional licenses or academic qualifications and experience, is duly recognized as having
3755      expertise in a relevant field of specialization, e.g. medical physics, radiation protection,
3756      occupational health, fire safety, quality assurance or any relevant engineering or safety
3757      specialty (IAEA 201 la)
3758    Qualified physicist - an individual who is competent to practice independently in the relevant
3759      medical subfield of medical physics or health physics. In general, a health physicist or
3760      medical physicist with appropriate training and experience regarding the medical use of x-rays
3761      is considered a qualified physicist. Ideally, persons should have certification from the
3762      American Board of Health Physics, the American Board of Medical Physics, the American
3763      Board of Radiology, or the American Board of Industrial Hygiene, to be considered a
3764      qualified expert in these respective fields.  For the purposes of this document, the relevant
3765      subfield of medical physics is diagnostic radiological physics. Certification, continuing
3766      education, and experience are factors toward demonstrating that an individual is a qualified
3767      physicist. Individual federal agencies may develop their own criteria for determining when a
3768      physicist is a "Qualified Physicist" as defined in this document.
3769    Qualified medical physicist - an individual who is competent to practice independently in the
3770      relevant subfield of medical physics. For the purposes of this document, the relevant subfield
3771      is diagnostic radiological physics.  Certification and continuing education and experience in
3772      the relevant subfield is one way to demonstrate that an individual  is competent to practice in
3773      that subfield of medical physics and to be a qualified medical physicist.
3774    Quality assurance - the function of a management system that provides confidence that specified
3775      requirements will be fulfilled
3776    Rad - the special (traditional or historical) name for the unit of absorbed dose. 1  rad = 0.01 J kg"
3777      \ In the SI system of units, it is replaced by the special name gray (Gy). 1 Gy =  100 rad
3778      (NCRP 2000). (see rad, rem, gray, and Sievert)
3779    Radiation Safety Officer - the individual whose responsibility it is to ensure adequate protection
3780      of workers and the public from exposure to ionizing radiation
3781    Radiation weighting factor, WR - a number (as specified in the System for Radiological
3782      Protection) by which the absorbed dose in a tissue or organ is multiplied to reflect the relative
3783      biological effectiveness of the radiation in inducing stochastic effects at low doses, the result
3784      being the equivalent dose (IAEA 2011 a)
3785    Radiography - the production of images on film or other record by the action of x-rays
3786      transmitted through the patient (NCRP 2003)
3787    Radiological Medical Practitioner - a health professional with specialist education  and training
3788      in the medical uses of radiation, who is competent to perform independently or to oversee
3789      procedures involving medical  exposure in a given specialty (IAEA 201 la) (see licensed
3790      independent practitioner)
3791    Reference dose, patient entrance reference dose (or reference air kerma, reference dose,
3792      cumulative dose, cumulative air kerma, KA,R) - the dose at the patient entrance reference
3793      point. For C-arm fluoroscopic equipment, this is also known as the interventional reference
3794      point, and is located along the central ray of the x-ray beam, 15 cm back from the isocenter
3795      toward the x-ray tube. The isocenter is the central point about which the C-arm  rotates.
3796      Reference dose is measured in Gy and is not the same as skin dose (IEC 2008).

3797    Reference level - a level used in medical imaging to indicate whether, in routine conditions, the
3798       dose to the patient in a specified radiological procedure is unusually high or low for that
3799       procedure
3800    Referring Medical Practitioner - a health professional who, in accordance with national
3801       requirements,  may refer individuals to a radiological medical practitioner for medical
3802       exposure (IAEA 201 la) (see licensed independent practitioner)
3803    Registry - central national repository for patient radiation dose and equipment parameter data
3804    Rem - the special (traditional or historical) name for the unit of dose equivalent numerically
3805       equal to the absorbed dose (D) in rad, modified by a quality factor (Q). 1 rem = 0.01 J kg"1. In
3806       the SI system  of units, it is replaced by the special name si evert (Sv), which is numerically
3807       equal to the absorbed dose (D) in gray modified by a radiation  weighting factor (COR). 1 Sv =
3808       100 rem (NCRP 2003). (see rad, rem, gray, and Sievert)
3809    Resolution - in the context of an imaging system, the output of which is finally viewed by the
3810       eye, it refers to the smallest size or highest spatial frequency of an obj ect of given contrast that
3811       is just perceptible. The resolution actually achieved with imaging lower contrast obj ects is
3812       normally much less, and depends upon many variables such as subject contrast levels and
3813       noise of the overall imaging system (NCRP 2003).
3814    Risk - the probability or quantifiable likelihood that a detriment to health will occur as a result of
3815       performing or not performing a medical procedure
3816    Roentgen - the special name for exposure, which is a specific quantity  of ionization (charge)
3817       produced by the absorption of x- or gamma-radiation energy in a specified mass of air under
3818       standard conditions. 1 R = 2.58 x 10"4  coulombs per kilogram (C kg'1) (NCRP 2003).
3819    Screening - the evaluation of an asymptomatic person in a population to detect a disease process
3820       not known to exi st at the time of evaluation
3821    Sievert (Sv) - the special SI name for the quantities equivalent dose or effective dose.
3822       Equivalent dose is the radiation protection quantity used for setting limits that help ensure that
3823       deterministic effects (e.g. damage to a particular tissue) are kept within acceptable levels.  The
3824       SI unit of equivalent dose is the J kg"1, and is abbreviated HT. It is numerically  equal to a
3825       radiation weighting factor (COR)  [or quality factor (Q)] multiplied by the absorbed dose in
3826       tissue T (DT,R). 1 Sv = 100 rad (NCRP 2003). The formula is:
3 827         HT = ZR roR DT,R or ZR QR DT;R
3828         where
3 829           COR = radiation weighting factor,
3830           DT,R = absorbed dose to tissue T from radiation type R, and
3831           QR= quality factor.
3833       Effective dose is the radiation protection quantity used for setting limits that help ensure that
3834       stochastic effects (i.e., cancer and genetic effects) are kept within acceptable levels. The SI
3 83 5       unit of effective dose is the J kg"1, and is abbreviated HE.  It is numerically equal to a radiation
3836       weighting factor (COR) multiplied by a tissue weighting factor (COT) and the absorbed dose from
3837       that radiation in tissue T (DT,R) in gray. Identically, it is the equivalent dose multiplied by a
3838       tissue weighting factor. 1 Sv = 100 rem (NCRP 2003). The formula is:
3839           HE = ZT COT ZR roR DT,R = ZT HT COT
3840           where
3841           HE = the effective dose (or effective dose equivalent) to the entire individual,
3842           COT = the tissue weighting factor in tissue T,


3843           HT = the equivalent dose (or dose equivalent),
3 844           COR = the radiation weighting factor, and
3845           DT,R = the absorbed dose to tissue T from radiation type R.
3846         (see rad, rem, gray, and Si evert)
3 847    Signal to noise ratio - the ratio of input signal to background interference.  The greater the ratio,
3 848      the clearer the image (NCRP 2003).
3849    Skin dose - radiation dose to the dermis, measured for example as entrance skin dose or peak
3850      skin dose
3851    Slice - a 2-dimensional reconstructed cross-sectional image depicting a patient's anatomy
3852      produced using x-rays, MRI, ultrasound, or other non-invasive means
3853    Step wedge - a device with various thicknesses of aluminum used to verify the consistency of
3854      the x-ray and film processing systems. Typically  each step of the stepwedge is about 1 mm
3855      thick and about 3 to 4 mm wide with at least 6 steps.  The device is placed on a film cassette
3856      and exposed under the exact same exposure parameters and geometry set up. The film is then
3857      developed and the steps are visually compared to the reference film identically exposed  and
3858      processed in fresh solutions under ideal conditions. A reproducible change of one step or
3859      more in density should signal the need for corrective action.
3860    Stochastic effects - effects, the probability of which, rather than their severity, is a function of
3861      radiation dose, implying the absence of a threshold. More generally, stochastic means random
3862      in nature (NCRP 2003).
3863     Supervision, general - means the procedure  is furnished under the supervising individual's
3864      overall direction and control, but the supervising individual's presence is not required during
3865      the performance of the procedure. Under general  supervision, the training of the personnel
3866      who actually perform the task and the maintenance of the necessary equipment and supplies
3867      are the continuing responsibility of the supervising individual  (adapted from (DHHS 2012a)
3868    Supervision, direct - means the supervising individual must be present in the local area (for
3869      physicians, in the office  suite) and immediately available to furnish assistance and direction
3870      throughout the performance of the procedure. It does not mean that the  supervising individual
3871      must be present in the room when the task is performed (adapted from (DHHS 2012a)).
3872    Supervision, personal - means a supervising individual must be in attendance in the room during
3 873      the performance of the task (adapted from (DHHS 2012a))
3874    Technique factor - operator selectable parameter affecting the x-ray beam (e.g., kV, mA, time)
3875    Tissue weighting factor, wT - multiplier of the equivalent dose to an organ or tissue, as given by
3876      the System for Radiological Protection, used for radiation protection purposes to account for
3877      the different sensitivities of different organs and tissues to the  induction  of stochastic effects
3878      of radiation (IAEA 201 la)
3879    Tomography - a special technique to show in detail images of structures lying in a
3880      predetermined plane of tissue, while blurring or eliminating detail in images of structures in
3881      other planes (NCRP 2003)
3882    Total effective dose equivalent (TEDE) - the sum of the deep-dose equivalent (for external
3883      exposures) and the committed effective dose equivalent (for internal exposures)
3884    Universal Protocol - A Joint Commission process developed to address wrong site, wrong
3885      procedure, and wrong person surgeries and other procedures.  The three  principal components
3886      of the Universal Protocol include a pre-procedure verification, site marking, and a timeout
3887      (The Joint Commission 2012a; The Joint Commission 2012b)

3888    Worker - any person who works, whether full time, part time or temporarily, for an employer
3889      and who has recognized rights and duties in relation to occupational radiation protection
3890      (IAEA 2011 a)

The guidance in this appendix is suitable for research involving diagnostic and interventional x-
ray procedures. It applies to radiation use indicated for research involving human subjects.
Examples might include evaluating new mammography protocol using lower kVp as
recommended by ICRP, virtual colonoscopy, and national lung screening trials. It excludes
radiation oncology research, in which radiation doses to subjects may be much higher. A
discussion of human subjects research ethics, patient benefit:risk considerations, and the role of
Institutional Review Boards is beyond the scope of this document, but is an essential process
prior to the conduct of research involving human subjects.

The risk from research protocols involving radiation use indicated for research, as described
above, can be categorized into groups. A useful approach is to group risk as minimal, minor to
intermediate, or moderate. The templates on the following pages are adapted from those used by
the NIH in 2012 (less than 1 mSv (100 mrem) "minimal" and 1 -50 mSv (100 mrem - 5 rem)
"minor to intermediate"). Doses above 50 mSv (5 rem) may be considered to range  from
moderate to substantial.  The specific ranges and text may be adjusted as required by the specific
IRB (NIH 2001; NIH 2008a; NIH 2008b; NIH 2010).  Another approach to selecting the dose
ranges and descriptors for these templates is shown below.
Classification schemes for use of E as a qualitative indicator of stochastic risk for diagnostic and
interventional x-ray procedures
Range of E
Radiation Risk Descriptor

Martin (2007)
Very low

Acceptable (in
context of the
expected benefit)
Expected Minimum
Individual or Societal Benefit
Justifiable expectation of very
substantial individual benefit
Adapted from: (ICRP 1991b; Martin 2007)

3917    Adapted from NIH TEMPLATE A (Total effective dose less than or equal to 1 mSv (100 mrem))
3919    This research study involves exposure to radiation from (insert type of procedure or procedures).
3920    Please note that this radiation exposure is not necessary for your medical care and is for research
3921    purposes only.
3923    The total amount of radiation you will receive in this study is from (insert maximum number) of
3924    (insert description of type of x-ray procedure). The Radiation Safety Committee has reviewed
3925    the use of radiation in this research study and has approved this use as involving minimal risk
3926    and necessary to obtain the research information desired.
3928    You will receive a total of (XX) mSv or (YY)  rem to your (insert highest-dosed organ, typically
3929    skin) from participating in this study.  All other parts of your body will receive smaller amounts
3930    of radiation.  Although each organ will receive a different dose, the amount of radiation exposure
3931    you will receive from this study is equal to a uniform whole-body exposure of less than (insert
3932    total effective dose value).  This calculated value is known as the "effective dose" and is used to
3933    relate the dose received by each organ to a single value.
3935    For comparison, the average person in the United States receives a radiation dose of 3 mSv (300
3936    mrem) per year from natural background sources, such as from the sun, outer space, and from
3937    radioactivity found naturally in the earth's air and soil. The dose that you will receive from
3938    participation in this research study is about the same amount you would normally receive in
3939    (insert number) months from these natural sources.
3941    While there is no direct evidence that the small radiation dose received from participating
3942    in this study is harmful, there is indirect evidence it may not be completely safe.  There
3943    may be an extremely small increase in the risk of cancer.

3946    Adapted from Nffl TEMPLATE B (7 mSv < Total effective dose = < 50 mSv) or (100 mrem <
3947    Total effective dose = < 5 rem)
3949    This research study involves exposure to radiation from (insert type of procedure or procedures}.
3950    Please note that this radiation exposure is not necessary for your medical care and is for research
3951    purposes only.
3953    The total amount of radiation you will receive in this study is from (insert maximum number}
3954    (scans or repetitions) of (insert description of type of x-ray procedure).  The Radiation Safety
3955    Committee has reviewed the use of radiation in this research study and has approved this use as
3956    involving low risk (more than minimal but less than moderate) and necessary to obtain the
3957    research information desired.
3959    Although each organ will receive a different dose, the amount of radiation exposure you will
3960    receive from this study is equal to a uniform whole-body exposure of less than (insert total
3961    effective dose value).  This calculated value is known as the "effective dose" and is used to relate
3962    the dose received by each organ to a single value.  The amount of radiation you will receive in
3963    this study is less than the annual radiation dose of 50 mSv per year  (5 rem per year) permitted for
3964    someone who works with radiation on a daily basis.
3966    For comparison, the average person in the United States receives a radiation  dose of 3 mSv (300
3967    mrem) per year from natural background sources, such as from the  sun, outer space, and from
3968    radioactivity found naturally in the earth's air and soil. The dose that you will receive from
3969    participation in this research study is about the same amount you would normally receive in
3970    (insert number) months from these natural sources.
3972    The effects of radiation exposure on humans have been studied for over 60 years.  In fact, these
3973    studies are the most extensive ever done of any potentially harmful  agent that could affect
3974    humans. In all these studies, no harmful effect to humans has been observed from the levels of
3975    radiation you will receive by taking part in this research study. However, scientists disagree on
3976    whether radiation doses at these levels are harmful. Even though no effects have been observed,
3977    some scientists believe that radiation can be harmful at any dose - even low doses such as those
3978    received during this research.
3980    While there is no direct evidence that the radiation dose received from participating in this
3981    study is harmful, there is indirect evidence it may not be completely safe. There may be a
3982    small increase in the risk of cancer.
3984    (INCLUSION OF THIS             IS OPTIONAL) Some people may be concerned that
3985    radiation exposure may have an effect on fertility or cause harm to future children.  The radiation
3986    dose you will receive in this research study is well below the level that affects fertility. In
3987    addition, radiation has never been shown to cause harm to the future children of individuals who
3988    have been exposed to radiation.  Harm to future generations has been found only in experiments
3989    on animals that have received radiation doses much higher than the amount you will receive in
3990    this study.


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