Merck Manual

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Annual Radiation Exposure in the United States

Annual Radiation Exposure in the United States

Source

Average Effective Dose (millisieverts)

Naturally occurring sources

Radon gas

2.3

Other terrestrial sources

0.2

Radiation from the sun and outer space

0.3

Natural radioactive material in the body

0.3

Subtotal

3.1

Manufactured sources

Diagnostic medical imaging*

3.0

Consumer products

0.1

Fallout from weapons testing

less than 0.01

Nuclear industry

less than 0.01

Subtotal

3.1

Total annual exposure

6.2

Other sources of exposure (per incident)

Airline travel

0.001–0.014/hour of flight

Dental x-rays

0.005

Chest x-ray (back-to-front view)

0.02

Chest x-ray (two views: back-to-front and side-to-side)

0.1

Mammography

0.4

Computed tomography of the head

2

Computed tomography of the chest, abdomen, or pelvis

6-8

Barium enema

8

Nuclear medicine (for example a bone scan)

4.2

*Average value. Most people receive much lower doses each year, from examinations such as dental x-rays and mammograms, whereas a smaller number of ill or injured people require numerous imaging tests and thus receive much larger doses.

Data from the National Council on Radiation Protection and Measurements. Ionizing radiation exposure of the population of the United States. NCRP Report No. 160 National Council on Radiation Protection and Measurements, Bethesda, MD, 2009.