New Methods for Reducing CT Scan Radiation Exposure

At the meeting of the American Association of Physicists in Medicine, which was held recently in Philadelphia, experts presented new proposals on how to reduce the amount of radiation people are exposed to during computed tomography (CT) scans. Investigators are aware that the doses patients receive during routine or emergency medical check-ups are fairly small, but they say that it can't hurt to reduce them even further. A typical CT scan exposes a person to between one and 14 millisieverts of radiation, Technology Review reports.

The research is extremely important when considering the number of CT scans performed annually in the United States alone. According to statistics for 2007, more than 70 million such tests were applied in a single year. According to a scientific report published in the December 2009 issue of the esteemed journal Archives of Internal Medicine, it would appear that these scans will produce a number of 29,000 cancer cases. A clear correlation between the use of CT scans and the development of various types of cancer has not yet been established, but some researchers are convinced that patients exposed to several imaging techniques in a short time frame are more prone to developing the condition.

“There is no direct evidence linking the radiation dose from CT scans to cancer. Doses delivered in a CT scan are of the same magnitude that we get every year from [cosmic] background radiation,” explains Mayo Clinic radiological physicist Cynthia McCollough. She explains that the 2009 study represents only a statistical calculation. The expert adds that one of the reasons motivating scientists to look for low-emissions methods of imaging their patients is the fact that some people need more than one scan. This is especially true in ER and trauma rooms, where accident victims need several scans before doctors can make a decision on the course of treatment they want to follow.

“Dose reduction depends on a case-by-case basis and the application. You could go lower or higher [than an eighth] depending on the part of body,” says Girijesh Yadava, a lead scientist at the Waukesha, Wisconsin-based GE Healthcare. Experts here presented a new method of conducting CT scans, that subjects the patient to only 1/8 the amount of radiation a normal scan does. The resulting image is just as detailed and useful as the one obtained through the normal procedure, GE experts explain.