Radiology: Volume 262: Number 2-February 2012
H. Benjamin Harvey, MD, JD Pari V. Pandharipande, MD, MPH
Computed tomography (CT) has become a routine part of medicine in the United States, with close to 70 million scans completed per year (1). While the clinical benefits of CT have always come hand-in-hand with the risk of radiation exposure, it is not until recently that this risk has reached the forefront of public aware-ness, prompting the federal government to take a renewed interest in CT regulation (2,3). Two primary factors are responsible. First, in 2009 and 2010, reports were released describing nearly 400 patients who received radiation overdoses during perfusion CT imaging of the brain, resulting in hair loss and skin changes in some patients, and garnering widespread public attention (4,5). Second, unrelated to these events, investigators have projected that radiation-induced cancer risks from CT may be substantial at the population level (6,7). One analysis projected that up to 29 000 Americans may develop future cancers as a result of CT scans performed in 2007 (6). While these studies have known limitations-in particular, they do not account for competing risks relevant to ordering in-dications, and utilize extrapolated risk projections from atomic bomb survi-vors, many of whom received much higher doses-they nonetheless have elevated public concern and support the need for greater vigilance in CT prac¬tices (6,7).
