Debbie Liebross describes herself as a bit of “a cancer phobic.” And she has reason to worry. Her mother died of lung cancer at age 69, and Liebross was once a social smoker, although she kicked the habit early.

 

   To keep anxiety at bay, the 55-year-old resident of Fort Lauderdale, Fla., has gotten a chest x-ray every few years for at least a decade to check out her lungs. Last year, when her family doctor suggested a baseline CT (computed tomography) scan of her heart to identify any developing problems, she decided to get her lungs scanned as well.

 

   Thousands of Americans like Liebross undergo imaging tests each day without hesitation. Costly medical imaging has become increasingly—and sometimes unnecessarily—commonplace. As a result, Americans today are exposed to seven times more radiation, via medical tests, than they were in the early 1980s, according to a report released this spring by the National Council on Radiation Protection and Measurements.

 

   “People can be exposed to a large amount of radiation,” says Timothy Bullard, M.D., an emergency room physician in Orlando, Fla., who has studied radiation exposure in patients. “They don’t realize it. Nor do the physicians. We don’t have any good way of tracking it right now.”

 

   A variety of influences have boosted Americans’ exposure to imaging radiation — from physician malpractice fears to aggressive marketing of body scans, virtual colonoscopies and other painless screening tools.

 

   But when radiation exposure is involved, how much is too much? And how does one weigh relative risks and benefits, particularly in light of proliferating imaging options?