Hall E J
Center for Radiological Research, College of Physicians and Surgeons of Columbia University, New York, NY 10032.
Radiographics. 1991 May;11(3):509-18. doi: 10.1148/radiographics.11.3.1852943.
The average number of diagnostic x-ray procedures per year in the United States equals the total population and results in an annual collective effective dose equivalent of about 9 million person-rem. Possible deleterious effects include (a) genetic consequences, the risks of which can be assessed only from animal studies; (b) carcinogenesis, which can be assessed from survivors of nuclear bombings and patients exposed for medical reasons; and (c) effects on the developing embryo or fetus. For stochastic endpoints such as cancer and genetic anomalies, it is estimated that the current practice of radiology in the United States increases spontaneous frequency by less than 1%. No single procedure is likely to produce harm to the conceptus, but an accumulation of procedures in a pregnant woman could be hazardous during the sensitive period of 8-15 weeks after conception, with microcephaly and mental retardation the most likely deleterious effects. The balance of risk versus benefit in diagnostic radiology is heavily weighted toward benefit, but the risks are there, and constant efforts are needed to reduce radiation doses to the minimum necessary.
在美国，每年诊断性X射线检查的平均次数与总人口数相等，导致的年集体有效剂量当量约为900万人-雷姆。可能的有害影响包括：（a）遗传后果，其风险只能通过动物研究来评估；（b）致癌作用，可根据核弹爆炸幸存者和因医疗原因接受照射的患者来评估；以及（c）对发育中的胚胎或胎儿的影响。对于诸如癌症和遗传异常等随机终点，据估计，美国目前的放射学实践使自发频率增加不到1%。没有哪一项检查可能对胎儿造成伤害，但孕妇多次检查积累起来，在受孕后8至15周的敏感期可能是危险的，最有可能的有害影响是小头畸形和智力迟钝。诊断性放射学中风险与益处的权衡严重倾向于益处，但风险确实存在，需要不断努力将辐射剂量降至必要的最低水平。
