UPDATED: JAMA study: CT & PET scan use soars

Use of CT scans tripled and MRI imaging quadrupled in 6 large health systems between 1996 and 2010, boosting radiation exposure considerably and creating possible health risks, according to a new study.

Details of the study by Dr. Rebecca Smith-Bindman of the University of California, San Francisco and her team are published in the latest issue of the Journal of the American Medical Association, or JAMA.

Smith-Bindman has long evaluated the increased use of imaging equipment and the radiation risks it can cause when used unnecessarily. She wrote a recent JAMA article, based on data from a previous Institute of Medicine report, concluding that CT scans and other imaging equipment could boost the risk of breast cancer.

For this larger study, the research team doesn't make any direct connections between imaging equipment and cancer. But the study and its corresponding media promotion notes the possible risks all the same: that CT and PET scans produce much higher levels of ionizing radiation than conventional radiology equipment, and that "evidence has linked exposure to radiation levels in this range with the development of radiation-induced cancers." The goal here, the researchers say, is to better why imaging use has increased beyond the boost of fee-for-service insurance reimbursements.

For the study, the team looked at electronic medical records involving 1 million to 2 million patients annually going back to 1996 through 2010, covering 30.9 million imaging tests (of which about one-third involved advanced CT scans, MRI scans or other advanced diagnostic imaging equipment). Why did these imaging methods become so popular? The researchers cite a number of reasons, such as better technology leading to wider use, patients and physicians wanting to use the machines more, and "defensive medical practices," where physicians order tests in order to rule something out and protect themselves from legal liability.

The imaging industry was quick to respond to the study, challenging its results. The Medical Imaging & Technology Alliance issued a statement asserting that the use of CT and PET scans and other medical imaging technologies is actually on the decline, based on a number of recent independent analyses of Medicare and private insurance data.

While more imaging has improved patient care, the researchers say their study points to possible health risks and expense as reasons to try to limit use of the machines. Imaging costs the healthcare system $100 billion each year, they note.

Editor's Note: This story was updated in the sixth paragraph to include a statement from the Medical Imaging and Technology Alliance.

- read the release
- check out the journal abstract
- more from Bloomberg
- here's the MITA statement