Mind and Body

Large Jump in Imaging Scans Since 1996

Many more imaging scans are done these days, greatly boosting the amount of radiation that patients receive and raising questions about overuse of these imaging methods, a new analysis concludes.

Photo of CT scanner

Researchers at the University of California-San Francisco studied millions of patients from six large HMOs from 1996 to 2010. They tracked 1 million to 2 million people each year.

They found that people had an average of just over one image exam each year. A little over a third of those exams were advanced tests - CT scans, MRIs, nuclear medicine, ultrasounds, and PET, or positron emission tomography.

On the upswing

The researchers found that CT scans grew by nearly 8 percent a year, MRIs by 10 percent a year, and ultrasounds by nearly 4 percent a year. Nuclear medicine scans, which are fairly uncommon, dipped by 3 percent a year, but PET scans grew rapidly from 2004 to 2010 -- by 57 percent annually. PET scans are most commonly used by oncologists, neurologists, and cardiologists.

MRI scans and ultrasound do not use radiation.

The researchers also found that the percentage of patients who received high or very high levels of radiation through scans also rose over the 15 years. Of those who received scans in 2010, nearly 7 percent received high annual radiation exposure and nearly 4 percent received very high annual exposure. Radiology procedures used to treat cancer were not included in this study.

Study author Rebecca Smith-Bindman, M.D., says the study didn't answer several basic questions: Does this extra radiation exposure pose a health risk? Do these advanced scans make a difference in diagnosing and treating illness?

For example, Dr. Hatabu said, scans make it much easier to diagnose bleeding in the brain.

Better guidelines needed

"We spend in the ballpark of $100 billion a year on medical imaging, and we need to invest some research dollars to figure out how best to spend these dollars and when to image more and when to image less," Dr. Smith-Bindman says. "The impact on health outcomes should be the driver of these decisions, rather than the fact that a new test has simply become available and we are enamored with the images."

Scanning technology has become much more accurate and useful over time, says Hiroto Hatabu, M.D., at Brigham and Women's Hospital in Boston, who co-wrote a commentary accompanying the study.

But he acknowledges that high-tech scans can be overused. "I think we can use information technology and try to control it in the future," he says. "And there are ongoing efforts to decrease the radiation doses and get the same information."

When you have a radiology procedure, you may want to ask your doctor about the amount of radiation used and the risks related to your particular situation. It's a good idea to keep a record of your past history of radiation exposure, such as previous CT scans and other types of X-rays, so that you can inform your doctor.

The study was published in a recent issue of the Journal of the American Medical Association.

Always talk with your health care provider to find out more information.

Online Resources

(Our Organization is not responsible for the content of Internet sites.)

American Academy of Orthopaedic Surgeons - X-rays, CT Scans and MRIs

Health Physics Society - Doses from Medical Radiation Sources

RadiologyInfo.org - Radiation Exposure in X-ray and CT Examinations

August 2012

What Is a CT Scan?

A CT scan is a procedure that uses a combination of X-rays and computer technology to make horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, organs, and blood vessels. CT scans are more detailed than standard X-rays.

CT scans may be performed to help diagnose tumors, investigate internal bleeding, or check for other internal injuries or damage.

The risks of radiation exposure may be related to the cumulative number of X-ray examinations or treatments over a long period of time. If you are pregnant or suspect that you may be pregnant, you should tell your doctor.

Always talk with your health care provider to find out more information.

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