Study: Imaging tests almost double Americans' radiation exposure

A new study concludes that American's radiation exposure is doubled by common imaging tests over normal levels, though imaging still isn't dangerous overall, the authors suggest.

The study, which appears in the New England Journal of Medicine, concludes that CT scans and nuclear imaging contribute to more than three-quarters of the exposure. More than 80 percent of such procedures are performed on outpatients, according to the researchers, who looked at records on about 1 million adults aged 18 to 64 in five regions across the U.S.

The authors note that the number of CT scans performed overall since 1992 has quadrupled, most frequently to do a myocardial perfusion scan to assess blood flow through the heart or trace damaged heart muscle. During the study period, ranging from 2005 to the end of 2007, almost 70 percent had one imaging procedure exposing them to radiation.

While the paper's lead author didn't seem worried about these results, other experts disagreed. For example, it appears that up to 2 percent of all cancers in the U.S. may be due to CT scans, something that suggests that the issue requires further study, according to Dr. Michael S. Lauer, director of the Divisions of Prevention and Population Sciences and of Cardiovascular Diseases at the U.S. National Heart, Lung, and Blood Institute. A separate study by Harvard researchers suggests that collective radiation exposure from CT scans alone can boost cancer risks by as much as 12 percent.

To learn more about the study:
- read this HealthDay News piece