CT Heart Scan Radiation: Cancer Risk?

Cancer 101: Cancer Explained

Study: Radiation From High-Tech Heart Scan May Increase Lifetime Cancer Risk

By Miranda Hitti
WebMD Medical News

Reviewed by Brunilda Nazario, MD

July 17, 2007 -- High-tech heart scans help evaluate heart disease, but their radiation may affect lifetime cancer risk, a new study shows.

The study, published in The Journal of the American Medical Association, isn't based on actual patients.

Instead, the researchers used computer software to predict lifetime cancer risk from a standard dose of radiation delivered by 64-slice computed tomography coronary angiography.

Never heard of 64-slice computed tomography coronary angiography? It's a type of CT scan that gives doctors a detailed look at the coronary arteries, which supply blood to heart muscle. The technique is quick, noninvasive, and becoming more popular.

CT Heart Scan Radiation Study

The new study comes from researchers including Andrew Einstein, MD, of New York's Columbia University Medical Center.

They estimated the odds of ever developing cancer associated with standard radiation exposure from a single heart scan using 64-slice CT coronary angiography.

The odds varied widely, were highest for young women, and depended on whether or not radiation-reducing technology was used.

Einstein's team estimates that women in their 20s may have the highest lifetime cancer risk from heart scan radiation, compared with other adults.

The study predicts that one in 143 women in their 20s might ever develop cancer linked to heart scan radiation. Those estimated odds improved to one in 219 when the researchers assumed that radiation-reducing technology was used in the heart scan.

The researchers predict the lowest lifetime cancer risk -- one in 5,017 -- for men in their 80s when radiation-reducing technology was used in the heart scans.

Heart Scan and Cancer Risk?

Because heart scans target the chest area, lung cancer stood out as a possible cancer risk related to heart scans. In women younger than 32, breast cancer was the most likely cancer risk.

But the researchers don't have any data on cancers in people who've gotten 64-slice heart scans. The heart scan technology is too new for that information, Einstein's team notes.

Why did the patients' age matter? Cancer usually develops slowly. Older patients might die of other causes before a cancer was diagnosed, according to the study.

The researchers call for further studies on the topic. For instance, they don't know what the lifetime cancer risk would be in people who get several heart scans over the years.

Meanwhile, Einstein and colleagues say they aren't against high-tech heart scans.

Heart disease is the No. 1 killer of U.S. men and women. With that in mind, the researchers recommend "cautious" use of CT coronary angiography, especially in young women, using the lowest effective dose of radiation.

Patients and their doctors should weigh the pros and cons of heart scans vs. other, more invasive diagnostic techniques, the researchers also suggest.

SOURCES: Einstein, A. The Journal of the American Medical Association, July 18, 2007; vol 298: pp 317-323. News release, JAMA/Archives.

© 2007 WebMD, Inc. All rights reserved.

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