CT Scans Cause Coming Cancer Epidemic


(Mar 10, 2011) The medical community is waking up to an enormous problem with radiation - mainly X-rays and CT scans - used to diagnose disease and injury. Patients are getting too much radiation, and the excess itself causes injuries, many years down the road, in a big uptick in the risk of cancer.

Even a "routine" CT scan of the abdomen, ordered thousands of times every day in the United States for patients with belly pain, carries a large risk of downstream cancer, just from that single scan.

Dr. Rebecca Smith-Bindman, MD, of the University of California San Francisco, estimates a 20-year-old woman who undergoes a CT scan of the abdomen and pelvis has a one in 250 chance over her lifetime of getting cancer just from that single dose of radiation. This number was in a talk she gave recently at UCSF, as reported by her colleague Bob Wachter, MD, a patient safety expert at UCSF.

More scary statistics are in two articles Dr. Smith-Bindman and her colleagues published in Archives of Internal Medicine in 2009.

There, they estimated that a single CT scan of the heart's arteries (called a CT coronary angiogram, and promoted as being safer than the usual test called a cardiac catheterization) would cause cancer in one in 270 women and one in 600 men who underwent the test at age 40.

One problem is a huge range in the amount of radiation used at different facilities. Dr. Smith-Bindman's group found a 13-fold variation from the lowest to the highest radiation exposure between scanners running the exact same imaging study.

She blames lax regulation by the Food and Drug Administration and lack of aggressive self-regulation by the medical physicists, working in hospitals, who are supposed to protect patients.

Most patients have no idea of the amount of radiation in one CT scan. It's estimated to be about 200,000 times more than the radiation you get from going through an airport whole-body scanner, or about 450 times more than a simple chest X-ray.

Once people start to appreciate the risk, they realize that the pretty pictures produces by CT scans can have a very expensive cost down the road. It's something to remember the next time you see a billboard advertising "whole body scans" for healthy checkups, or "virtual colonoscopies" (to pick two examples of the heavily hyped types of CT scans now available).
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