NCRP Sources of Radiation Exposure - 2009
Sources of Radiation Exposure
Industrial < 0.1%
Occupational <0.1% ,	Consumer 2%
Computed Tomography 24%
Nuclear Medicine 12%
Interventional Fluoroscopy 7%
Conventional Radiography/Fluoroscopy 5%
Terrestrial 3%
Internal 5%
Space 5%
Radon &Thoron 37%

Average Annual Radiation Dose








Sources
Radon &
Thoron
Computed
Tomography
Nuclear
Medicine
Interventional
Fluoroscopy
Space
Conventional
Radiography/
Fluoroscopy
Internal
Terrestrial
Consumer
Occupational
Industrial
Units
mrem (United States)
mSv (International)
228 mrem
2.28 mSv
147 mrem
1.47 mSv
77 mrem
0.77 mSv
43 mrem
0.43 mSv
33 mrem
0.33 mSv
33 mrem
0.33mSv
29 mrem
0.29 mSv
21 mrem
0.21 mSv
13 mrem
0.13 mSv
0.5 mrem
0.005 mSv
0.3 mrem
0.003 mSv
(Source: National Council on Radiation Protection & Measurements, Report No. 160)
Description of Medical Terms:
•	Computed tomography (CT): A medical imaging procedure that uses x-rays to show cross-sectional
images of the body. Also called computerized axial tomography (CAT) scanning.
•	Interventional fluoroscopy: The use of ionizing radiation to guide small instruments such as
catheters through blood vessels or other pathways in the body.
•	Conventional radiography and fluoroscopy: Radiography is the use of x-ray machines by doctors
and dentists to view the human body. Fluoroscopy is a medical technique used by doctors to take
real-time moving images of internal structures in the body by placing a patient between a
fluorescent screen and an x-ray source.
•	Nuclear medicine: Radioactive elements or tracers that are given intravenously or orally. A
gamma camera detects gamma rays emitted by the tracer. These data are fed into a computer
where they are used to produce images and other information about the body's organ system.

-------