Are Medical Tests a Hazard?
Say you have abdominal pain, and your doctor suspects diverticulitis, a digestive disorder. He or she will likely order a CT (computed tomography) scan, a procedure that uses radiation to capture cross-sectional images of your insides and transmit them to a computer. By compiling the images, the doctor creates a 3D picture of the body region he's investigating in order to diagnose you.
But this quick test, which is increasingly popular, exposes you to a potentially dangerous dose of radiation, says David Brenner, PhD, a professor of radiation biophysics at Columbia University Medical Center. A CT scan of the abdomen, for example, delivers at least 50 times more radiation than an x-ray. Such high dosages could be damaging: 1.5 to 2 percent of all cancers in the United States may be linked to CT scans, according to a recent study coauthored by Dr. Brenner in the New England Journal of Medicine. Women are at greater risk: For example, a 20-year-old woman who gets a coronary CT angiogram has a one in 143 chance of getting cancer, compared with a one in 686 chance for a man of the same age, according to estimates from a 2007 study in the Journal of the American Medical Association. It may be that the female breast is more sensitive than male breast tissue, notes Andrew Einstein, MD, lead author of the study.
Medical radiation is a powerful tool; a CT scan can detect kidney stones, coronary blockages, and brain tumors. But "little thought is given to a person's cumulative exposure to radiation," says Mark S. Smith, MD, chairman of emergency medicine at Washington Hospital Center, in Washington, D.C. Experts offer these tips for limiting exposure without compromising your diagnosis:
Ask your doctor if a CT scan is necessary. Sometimes an x-ray or an imaging tool that doesn't use radiation, such as ultrasound, can be used instead.
Check that the facility performing your procedure is accredited by the American College of Radiology (ACR). The ACR endorses capturing clear images with as low a dose as possible. Doctors and staffers must also meet training standards and equipment must be checked regularly.
Ask if the dosage on the CT scanner can be adjusted for children or small adults. A lower body mass requires less radiation for the test.
Avoid unnecessary repeat procedures. If you've had a CT scan already, have results sent to your current doctor. If he insists on more images, ask why.
Don't get a whole-body scan unless it's a medical must. Healthy people can get screened, but there's no need to expose yourself to radiation just to ease your mind.
Originally published in Ladies' Home Journal, May 2008.