Cancer risks and radiation exposure from computed tomographic scans: how can we be sure that the benefits outweigh the risks?

T HE INTRODUCTION OF THE COMPUTED TOmographic (CT) scanner ushered in a new era of internal medicine diagnosis. Conditions that once required laparoscopy for diagnosis could now be diagnosed on the radiology reading board. The previously opaque anatomy of the living brain could now be visualized. The best part was that the test was “noninvasive,” fast, and painless. With the exception of patients who were allergic to dye or had renal insufficiency, CT was considered completely safe. No wonder it had such a significant effect on the practice of medicine.