Medical Radiation: Friend and Foe

A healthWise column by Laurine Brown, Ph.D., MPH

X-rays are a remarkable medical tool, enabling us to see inside the body without a surgeon's scalpel. Besides spotting injuries, X-rays (including computer tomography or CT scans) help us screen, diagnose, and even treat (as for cancer) various medical conditions from head to toe. We use them a lot. Seven out of ten Americans will get a medical or dental X-ray this year.

But concerns are mounting about harms of our zealous use of these imaging techniques, especially excess cancer, but also cataracts and skin burns. X-rays emit ionizing (or high energy, electromagnetic) radiation. When these high energy rays pass through the body, they can create “free radicals” which can damage DNA in cells. With the aid of an antioxidant-rich diet, our body often repairs these cells (or they die with very high doses). But sometimes cell repair is faulty; cells act wildly and in time may grow into cancer. A new study from the National Cancer Institute (NCI) projects 29,000 extra cancers from the 72 million CT scans that Americans got in 2007 alone. Nearly 15,000 of those cancers could be fatal, they say. This is concerning, since Americans' “lifetime risk” of developing cancer is stunningly high already - a 1 in 2 chance for men, and a 1 in 3 chance for women. Children, younger adults and women are especially vulnerable. While some scientists feel these predictions are too high, most agree more safeguards are urgently needed.

Today, Americans receive far more medical radiation than ever before - the average radiation dose per person has increased almost 500 percent since 1982. Nearly half of all exposures come from CT, and the number of CT scans is growing by 10 percent yearly, whether medically warranted or not. It's often said that a chest X-ray is comparable to flying across the continent, but a CT scan rivals 500 transcontinental flights.

Also of concern, recent studies have found needlessly high and inconsistent radiation doses for the same procedures from one hospital to another. For example, of more than 1,100 patients studied in four San Francisco hospitals, some received 13 times more radiation from CT of the same body part than others. In light of these findings and other disturbing (though still rare) medical mistakes, in February 2010 the US Food and Drug Administration (FDA) announced plans to more stringently regulate three of the most potent forms of medical radiation, including the increasingly popular CT scans. Medical groups are also seeking ways to minimize the amount of radiation in each scan or eliminate unnecessary X-rays. One effective tool that has minimized overuse of scans requires doctors to list a reason for ordering radiation-emitting studies, and a computer program feeds back an “appropriateness score” indicating if it is likely unnecessary.

Minimizing Your Risks

There is no doubt that medical radiation saves countless lives. But, as with most things, it can also do harm. While more radiation safeguards are put in place by government and the medical community, there is much you can do, personally, to protect yourself from unnecessary harm.

o Educate yourself about risks. Explore online calculators www.xrayrisk.com and http://www.epa.gov/rpdweb00/understand/calculate.html that estimate your dose and cancer risk from CT scans, simple X-rays, and more. For more information see www.epa.gov/radiation and http://www.fda.gov/Radiation-EmittingProducts/

o Ask your health care professional how an X-ray will help determine what's wrong or guide your treatment. You have a right to know. In some cases a CT scan can be replaced by a simpler test (like conventional X-rays) or tests that don't involve radiation (like ultrasound or MRI). But don't refuse an X-ray if medically needed, since risks of avoiding it are usually greater than the risks from the radiation.

o Don't insist on an X-ray. Sometimes providers give in to people who demand X-rays, even if it isn't medically needed.

o Tell the provider if you are (or may be) pregnant before having an x-ray of your abdomen or lower back. The fetus is very vulnerable since it is growing so quickly.

o Keep up on new mammography information. Mammography (breast x-ray) is important in early detection of breast cancer. But questions remain about the most effective use. Women likely to benefit most from mammography are those with symptoms, post-menopausal, or with a personal/family history of breast cancer. Consult your doctor for your personal risks/benefits.

o Ask if your dentist uses the faster (E or F) speed film for X-rays. The radiation dose is lower that conventional D speed film, but costs and other benefits are similar. Using digital imaging detectors instead of film further reduces radiation doses.

o Ask if a protective shield can be used (like a lead apron) for yourself and especially your children (e.g., gonad shield to protect sex organs from radiation “scatter”, or full-body apron with thyroid collar during dental X-rays).

o Know your X-ray history. Just as you keep a list of medications or immunizations, keep a list of imaging records including dental x-rays, for everyone in the family. Carry it in your wallet. When an x-ray is taken, record date, type of exam, referring physician, and address where X-ray is kept. Show the card to your medical provider to avoid unnecessary duplication of X-rays of the same body part. See sample: http://www.fda.gov/downloads/Radiation-EmittingProducts/ResourcesforYouRadiationEmittingProducts/Consumers/UCM142630.pdf.


References

o Bogdanich W. “The Radiation Boom: As Technology Surges, Radiation Safeguards Lag.” The New York Times. January 27, 2010. http://www.nytimes.com/2010/01/27/us/27radiation.html.

o Bogdanich W. “The Radiation Boom: Radiation Offers New Cures, and Ways to Do Harm.” The New York Times. January 24, 2010. http://www.nytimes.com/2010/01/24/health/24radiation.html.

o Bogdanich W. “The Radiation Boom - Case Studies: When Medical Radiation Goes Awry.” The New York Times. January 27, 2010. http://www.nytimes.com/2010/01/27/us/27RADIATIONSIDEBAR.html?ref=us.

o Bogdanich W, Rebelo K. “The Radiation Boom -They Check the Medical Equipment, But Who's Checking Up On Them?” The New York Times. January 27, 2010. http://www.nytimes.com/2010/01/27/us/27sideradiation.html?ref=us.

o Bogdanich W, Ruiz R. “The Radiation Boom - FDA to Increase Oversight of Medical Radiation.” The New York Times. February 9, 2010. http://www.nytimes.com/2010/02/10/health/policy/10radiation.html.

o Environmental Protection Agency. “Calculate Your Radiation Dose.” US Environmental Protection Agency. Updated October 26, 2009. http://www.epa.gov/rpdweb00/understand/calculate.html.

o Environmental Protection Agency. “Radiation Risks and Realities” US Environmental Protection Agency, Office of Air and Radiation, Office of Radiation and Indoor Air. EPA-402-K-07-006. May 2007. http://www.epa.gov/rpdweb00/docs/402-k-07-006.pdf/

o Food and Drug Administration. “Radiation-Emitting Products - Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging.” US Food and Drug Administration, US Department of Health and Human Services.Updated February 9, 2010. http://www.fda.gov/Radiation-EmittingProducts/RadiationSafety/RadiationDoseReduction/ucm199904.htm

o Food and Drug Administration. “Reducing Radiation from Medical X-rays. FDA Consumer Health Information. US Food and Drug Administration. February 19, 2009. http://www.fda.gov/downloads/ForConsumers/ConsumerUpdates/ucm095824.pdf.

o Food and Drug Administration. “We Want You to Know About X-Rays: Get the Picture on Protection.” US Food and Drug Administration, US Department of Health and Human Services. Updated April 30, 2009. http://www.fda.gov/radiation-emittingproducts/resourcesforyouradiationemittingproducts/consumers/ucm142627.htm#7

o Food and Drug Administration. “White Paper: Initiative to Reduce Radiation from Medical Imaging.” Administration Center for Devices and Radiological Health, US Food and Drug Administration. February 2010. http://www.fda.gov/downloads/Radiation-EmittingProducts/RadiationSafety/RadiationDoseReduction/UCM200087.pdf.

o Food and Drug Administration. “X-ray Record Card.” Undated. Viewed February 15, 2010. http://www.fda.gov/downloads/Radiation-EmittingProducts/ResourcesforYouRadiationEmittingProducts/Consumers/UCM142630.pdf

o Knox R. “Radiation From CT Scans May Raise Cancer Risk.” National Public Radio. December 15, 2009. http://www.npr.org/templates/story/story.php?storyId=121436092.

o X-RayRisk.com. “Radiation Risk Calculator.” Viewed February 15, 2010. http://www.xrayrisk.com/