Radiation exposure has been in the news lately with the recent events in Japan, making the public more aware of possible radiation hazards from other sources.

Radiation exposure has been in the news lately with the recent events in Japan, making the public more aware of possible radiation hazards from other sources.

How much radiation is in a single chest X-ray? Not a whole lot, but why get an X-ray if you don't need it?

Diagnostic X-rays are the largest man-made source of radiation exposure to the general population, contributing about 14 percent of the total annual exposure worldwide from all sources.

A study published in 2004 in Lancet researched the risk of development of cancer with diagnostic X-rays in 14 countries. The researchers found that 0.6 percent to 3 percent of the cumulative risk of cancer to age 75 could be attributable to diagnostic X-rays in the countries studied.

The U.S. Nuclear Regulatory Commission recommends that beyond background radiation, the average person should limit their exposure to less that one millisevert a year. A single CT scan, for example, can expose the patient to one millisevert. However, the radiation risks need to be weighed with the medical benefits of performing the diagnostic X-ray.

Take home message for the average patient? Be aware of radiation risks when getting diagnostic X-rays. Discuss the risks/benefits of diagnostic tests with your physician, especially when getting tests that expose you to high levels of radiation.