Rise in CT scans spark radiation fears

risks of patients' increased exposure to radiation, Time reports.

Dr Rebecca Smith-Bindman, a professor of radiology and biomedical imaging at the University of California San Francisco, and her colleagues report that, between 1996 and 2010, the use of computed tomography (CT) scans nearly tripled, from 52 scans per 1 000 patients, to 149 scans per 1 000 patients, and rates of magnetic resonance imaging (MRI) increased fourfold, from 17 scans per 1 000 patients, to 65 scans per 1 000 patients. Nuclear medicine and ultrasound rates also soared.

The study also found that the percentage of patients who received high exposure to radiation of greater than 20 millisieverts to 50 millisieverts, or very high, which is greater than 50 millisieverts, during a given year doubled, Bloomberg writes.

The general population is exposed to about 6.2 millisieverts of radiation each year, half from natural sources such as the sun and the rest from encounters such as medical imaging, according to the US Nuclear Regulatory Commission. The commission limits adults working with radioactive material to exposure of 50 millisieverts a year.

"There has been an enormous amount of literature that shows radiation in the range used for CTs is associated with cancer," San Francisco Chronicle quotes Smith-Bindman as saying.

"There are benefits to imaging and some harm. We need to have much more informed decisions and choices about when to use imaging."