How Much Radiation Are You Getting?


We absorb radiation from a variety of sources. How much is too much? Experts say 3 mSv per year is probably OK for most of us; 20 mSv for those who must have medical tests.


CT scan, full body

10–12 mSv

CT scan, chest or pelvis

4–8 mSv

Natural background radiation (from sunlight, radon gas, etc.) from living in high-altitude cities (e.g., Denver, Salt Lake City)

6 mSv (per year)

Natural background radiation from living at sea level (e.g., Chicago)

3 mSv (per year)


1–2 mSv

High-mileage frequent flying (100,000–450,000 miles per year)

1–6.7 mSv

X-ray of chest (or ankle to look for broken bones)

0.1–0.6 mSv

DEXA (bone-density) scan

0.01–0.05 mSv

Dental X-ray (bitewing)

0.02 mSv

Single airplane flight, coast-to-coast

0.01–0.03 mSv

*mSv=millisievert, the scientific unit of measurement for radiation dose. At high levels, radiation can mutate the structure (genetic components) of a body’s dividing or reproducing cells and increase cancer risks. Sources: American College of Radiology; Radiological Society of North America; American Association of Physical Medicine; The New England Journal of Medicine; University of California, San Francisco, Cancer Center.