New research has found that it is a regularly occurring practice at hundreds of hospitals to allow chest CT scans, which typically dose out 45 millisieverts (mSv) of radiation — and sometimes substantially more — twice in the same day. In contrast, the average chest X-ray gives off 0.02 mSv of radiation.
Back-to-back mega-doses of radiation! That sounds like something out of the “Incredible Hulk.” But unfortunately, this is not a scene from a comic book or movie. It is taking place in hospitals all across the United States.
New research has found that it is a regularly occurring practice at hundreds of hospitals to allow chest CT scans, which typically dose out 45 millisieverts (mSv) of radiation — and sometimes substantially more — twice in the same day.1 In contrast, the average chest X-ray gives off 0.02 mSv of radiation. The levels of radiation a patient is exposed to in one CT scan are only questionably safe — now in all these instances, that amount is doubled.
The study, performed through the Center for Medicare and Medicaid Services, examined Medicare outpatient claims from 2008 and discovered wide variations in the use of CT scans. Some hospitals will not perform two scans in a day on the same patient or do it less than 1 percent of the time. Others, however, allow double scanning in a day to occur more than 80 percent of the time.
The data was broken down by state as well as by each individual hospital. Overall, approximately 75,000 patients across the country received two CT scans in one day in 2008. The scans are performed slightly differently, as one employs iodine contrast to monitor blood flow and the other does not. But according to most radiologists, as well as common sense, they are almost never both necessary. A physician should be choosing one method over the other, depending on what it is they are assessing.
One CT scan of the chest area is the equivalent of roughly 350 standard x-rays — which is already a tremendous amount of radiation to subject a patient to. So two scans is 700 chest x-rays worth of radiation…in one day. Seems a little excessive in any possible scenario.
The research determined that the national average among Medicare patients receiving double scans is 5.4 percent. However, there were over 200 hospitals that gave two scans in a day to more than 30 percent of their Medicare patients. Of course, this study only focused on Medicare patients; double scanning was found to be just as common among privately insured patients of all ages.
The use of CT scans stems from their ability to provide three-dimensional images far more detailed and flexible than normal X-rays. Since many doctors rely heavily on them for diagnoses, the number of CT scans performed in the United States has increased 23-fold from three million in 1980 to about 70 million by 2007.
Despite assurances from doctors that the benefits of getting such accurate diagnostic images outweigh the risks, there is evidence that indicates that the radiation received from CT scans increases cancer risk by a substantial margin. A 2009 study at four San Francisco hospitals found the median doses of radiation delivered during CT scans was higher than previously thought. Also, the radiation levels varied wildly for the same procedure from hospital to hospital and even within the same institution.
Another 2009 study, published in the Archives of Internal Medicine, concluded that approximately 4,100 new cancers would result from CT scans of the chest in 2007.2 How many of these might be avoided if double scanning was procedurally banned?
In fact, CT scans should probably not be used as a diagnostic tool option, except for the very sickest patients for whom no other diagnostic tool will work. In those who are generally healthy, with only a mild form of illness, the risk of developing cancer should far outweigh the potential benefit provided when there are other methods of determining cause that are safer. And when it comes to double scans on the same day — or during any contiguous time period, make sure your doctor provides a compelling reason. But again, remember that according to most radiologists, they are almost never both necessary.
So go armed to your physician with the knowledge that CT scans are not usually your best option and double scans are almost never okay. Be your own best advocate in the hospital and when obtaining medical services anywhere, because the medical system often will not take care of you the way it should.
1 Bogdanich, Walt and Craven McGinty, Jo. “Medicare Claims Show Overuse for CT Scanning.” The New York Times. 17 June 2011. The New York Times Company. 3 July 2011. <http://www.nytimes.com/2011/06/18/health/18radiation.html>.
2 Amy Berrington de González, DPhil; Mahadevappa Mahesh, MS, PhD; Kwang-Pyo Kim, PhD; Mythreyi Bhargavan, PhD; Rebecca Lewis, MPH; Fred Mettler, MD; Charles Land, PhD, “Projected Cancer Risks From Computed Tomographic Scans Performed in the United States in 2007.” Archives of Internal Medicine. Vol. 169 No. 22, Dec 14/28, 2009 <http://archinte.ama-assn.org/cgi/content/abstract/169/22/2071>