Researchers Say Medical Radiation Overused, Creating Health Risks

Radiation has been a great boon to medicine, helping doctors reveal hidden problems, including broken bones, lung lesions, heart defects and tumors. It can be used to treat and sometimes cure certain cancers.

Now researchers are pointing to its potentially serious side effects: the ability to damage DNA and, 10 to 20 years later, to cause cancer. CT scans alone, which deliver 100 to 500 times the radiation associated with an ordinary X-ray and now provide three-fourths of Americans’ radiation exposure, are believed to account for 1.5 percent of all cancers that occur in the United States.

Numerous experts, including some radiologists, are now calling for more careful consideration before ordering tests that involve radiation.

The trend was reported recently in The New York Times.

“All imaging has increased, but CTs account for the bulk of it,” said Dr. Rebecca Smith-Bindman, a specialist in radiology and biomedical imaging at the University of California, San Francisco. “There’s clearly widespread overuse. More than 10 percent of patients each year are receiving very high radiation exposures.”

The trick to using medical radiation appropriately, experts say, is to balance the potential risks against known benefits. But despite the astronomical rise in recent years in the use of radiation to obtain medical images, this balancing act is too often ignored, experts say. The consequences include unnecessary medical costs and risks to the health of patients.

Patients may be surprised to learn that some of the newest uses of radiological imaging, including CT scans of coronary arteries to look for calcium buildup, have not been tested in scientifically designed clinical trials, and their true benefits are at best a guess. Experts have estimated that widespread use of coronary artery scans, which deliver 600 times the radiation of a chest X-ray, could result in 42 additional cases of cancer for every 100,000 men who have the procedure, and 62 cases for every 100,000 women who do.

For every 1,000 people undergoing a cardiac CT scan, the radiation adds one extra case of cancer to the 420 that would normally occur. This risk may seem inconsequential, but not to someone who gets a cancer that could have been prevented.

Complicating the matter is the enormous variation — sometimes tenfold or more — in the amounts of radiation to which patients are exposed from the same procedure at different institutions, or even at the same institution at different times.

Although the cancer-causing effects of radiation are cumulative, no one keeps track of how much radiation patients have already been exposed to when a new imaging exam is ordered. Even when patients are asked about earlier exams, the goal is nearly always to compare new findings with old ones, not to estimate the risks of additional radiation.

After an extensive review of the environmental causes and risk factors for breast cancer, the Institute of Medicine reported last year that sufficient evidence of risk was found only for combined hormone therapy used by postmenopausal women and exposure to ionizing radiation, at doses much higher than those received during a mammogram.

Everyone is exposed to a certain amount of background radiation — about three millisieverts a year from cosmic rays, radon gas and the earth’s radioactive elements. By 1980, according to The Harvard Health Letter, various introduced sources, like medical tests, nuclear power plants, nuclear fallout, television sets, computer monitors, smoke detectors and airport security scanners, added another 0.5 millisieverts per year.

Now, however, the amount of radiation used medically rivals that of the background radiation, adding three millisieverts each year to the average person’s exposure. (A mammogram involves 0.7 millisieverts, a dose that is doubled with a 3-D mammogram.)

There are many reasons for this increase. Doctors in private practice who have bought imaging equipment tend to use it liberally to recoup the expense. The same goes for hospitals just a few miles apart that needlessly duplicate certain equipment so they can boast of having the latest and greatest capacity to detect disease.

According to a new study, the rise in medical imaging clearly goes beyond financial motives. Dr. Smith-Bindman and her colleagues reported in June in The Journal of the American Medical Association that a dramatic rise in imaging rates from 1996 to 2010, including a tripling of CT scans, occurred in six large prepaid health systems where the financial incentive ought to have encouraged fewer, not more, tests. The increased testing doubled the proportion of patients who received high or very high radiation exposures.

By 2010, the researchers reported, 20 CT scans were performed for every 100 adult patients; for every 100 patients ages 65 to 75, about 35 CT scans were done. And among the 10 to 20 percent of children in the study who underwent a single CT scan of the head, radiation doses were in the range previously shown to triple the risk of later developing brain cancer or leukemia.

Dr. Smith-Bindman urged patients to participate in the decision to undergo medical imaging. She said, “Patients should ask, ‘What is this test for? Do I need it? Why? Do I need it now?’ ”
Kreisman Law Offices has been handling Illinois radiation errors and Illinois product defect matters for over 36 years in and around Cook County, including Bridgeport, Evanston, Melrose Park and Highland Park.

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