Sinclair W K
National Council on Radiation Protection and Measurements, Bethesda, Maryland 20814.
Radiat Res. 1987 Nov;112(2):191-216.
Radiation protection concerns the risk of stochastic late effects, especially cancer, and limits on radiation exposure both occupationally and for the public tend to be based on these risks. The risks are determined, mainly by expert committees, from the steadily growing information on exposed human populations, especially the survivors of the atomic bombs dropped in Japan in 1945. Risks of cancer estimated up to the early 1980s were in the range 1 to 5 X 10(-2)/Sv, but recent revisions in the dosimetry of the Japanese survivors and additional cycles of epidemiological information suggest values now probably at the high end of this range. These are likely to require an increase in the values used for radiation protection. A major problem with risk estimation is that data are available only for substantial doses and must be extrapolated down to the low-dose region of interest in radiation protection. Thus the shape of the dose-response curve is important, and here we must turn to laboratory research. Of importance are studies involving (1) dose rate, which affects the response to low-LET radiation and often to high-LET radiation as well; (2) radiation quality, since the shapes of the dose-response curves for high- and low-LET radiation differ and thus the RBE, the ratio between them, varies, reaching a maximum value RBEM at low doses; and (3) modifiers of the carcinogenic response, which either enhance or reduce the effect of a given dose. Radiation protection depends both on risk information, and especially also on comparisons with other occupational and public risks, and on research, not only for extrapolations of risk to low doses but also in areas where human information is lacking such as in the effects of radiation quality and in modifications of response.
辐射防护关注随机迟发效应的风险，尤其是癌症风险，职业和公众辐射暴露限值往往基于这些风险。这些风险主要由专家委员会根据不断增加的受照人群信息来确定，特别是1945年日本原子弹爆炸的幸存者。到20世纪80年代初估计的癌症风险在1至5×10⁻²/Sv范围内，但最近对日本幸存者剂量测定的修订以及更多轮的流行病学信息表明，现在的值可能处于该范围的高端。这可能需要提高用于辐射防护的值。风险估计的一个主要问题是，数据仅适用于大剂量情况，必须外推到辐射防护中感兴趣的低剂量区域。因此，剂量反应曲线的形状很重要，在这里我们必须依靠实验室研究。重要的研究包括：（1）剂量率，它影响对低线性能量传递辐射的反应，通常也影响对高线性能量传递辐射的反应；（2）辐射品质，因为高线性能量传递和低线性能量传递辐射的剂量反应曲线形状不同，因此它们之间的比值，即相对生物效应（RBE）会变化，在低剂量时达到最大值RBEM；（3）致癌反应的调节剂，其可增强或降低给定剂量的效应。辐射防护既依赖于风险信息，尤其还依赖于与其他职业和公众风险的比较，以及研究，不仅用于将风险外推到低剂量，还用于缺乏人类信息的领域，如辐射品质的影响和反应的修饰。
