Coronary Calcium Scans Can Raise Cancer Risks

July 14 -- MONDAY, July 13 (HealthDay News) -- When weighing whether a coronary calcium scan is worth the risk, a new study suggests that arriving at an answer won't be clear-cut or easy.

A team of researchers from the U.S. National Cancer Institute and Columbia University found that the average range of radiation exposure from having such a screening test every five years would cause 42 additional cases of cancer among 100,000 men and 62 additional cases among 100,000 women. However, given the wide range of radiation doses seen in the study, the increase could be as low as 14 cases and as high as 200 cases among 100,000 men, and as low as 21 cases or as high as 300 cases among 100,000 women.

This is an issue of growing importance on the American medical scene, said Dr. Andrew J. Einstein, director of cardiac computed tomography research at Columbia University, and a member of a team that reports its findings in the July 13 issue of the Archives of Internal Medicine.

"There has been great interest recently in computed tomography, owing to the fact that the number of CAT scans has grown tremendously in the United States," Einstein said. "The National Council on Radiation Protection & Measurement estimates that 70 million are done per year."

The study in which Epstein took part looked at a form of computed tomography that scans for calcium deposits in heart arteries. CAC scanning, as it is called, is one of the lesser-done forms of computed tomography, but a private organization, Screening for Heart Attack, Prevention and Education, has proposed that it be done annually on 50 million Americans, and a new Texas law mandates health insurance coverage of the procedure.

The new study looked at what a dose of radiation in a single CAC scan would be, and found an enormous variation. There is no single protocol -- set of rules -- for such a scan, which can be done on a variety of equipment, Einstein said. "This was first proposed in 1990, and CT scanner technology has changed, so it is not clear what the protocol might be," he noted.