CT与肿瘤新英格兰杂志.pdfVIP

T h e n e w e ng l a nd j o u r na l o f m e dic i n e review article current concepts Computed Tomography — An Increasing Source of Radiation Exposure David J. Brenner, Ph.D., D.Sc., and Eric J. Hall, D.Phil., D.Sc. he advent of computed tomography (ct) has revolutionized di- From the Center for Radiological Re- agnostic radiology. Since the inception of CT in the 1970s, its use has increased search, Columbia University Medical Cen- Trapidly. It is estimated that more than 62 million CT scans per year are cur- ter, New York. Address reprint requests to Dr. Brenner at the Center for Radiologi- rently obtained in the United States, including at least 4 million for children.1 cal Research, Columbia University Medical By its nature, CT involves larger radiation doses than the more common, conven- Center, 630 W. 168th St., New York, NY 10032, or at djb3@. tional x-ray imaging procedures (Table 1). We briefly review the nature of CT scanning and its main clinical applications, both in symptomatic patients and, in N Engl J Med 2007;357:2277-84. a more recent development, in the screening of asymptomatic patients. We focus Copyright © 2007 Massachusetts Medical Society. on the increasing number of CT scans being obtained, the associated radiation doses, and the consequent cancer risks in adults and particularly in children. Al- though the risks for any one person are not large, the increasing exposure to ra- diation in the population may