Bross I D, Ball M, Falen S
Am J Public Health. 1979 Feb;69(2):130-6. doi: 10.2105/ajph.69.2.130.
Most exposure to low-level ionizing radiation, both diagnostic x-rays and nuclear radiation, occur in the range between 100 milirads and 10 rads--the "one rad range". In the past, the estimates of hazards in this range have been obtained by linear extrapolation from data on persons who were exposed to much higher dosages, generally in the centirad range used in radiotherapy of non-malignant disease. This article presents the first dosage response curve for the one rad range ever to be developed directly from data on men exposed to ordinary diagnostic radiation. The findings are based on approximately 220 men with non-lymphatic leukemia and more than 270 random-sample controls from the Tri-State Survey. The new findings suggest that the estimates previously obtained by extrapolation from high dosage levels to low dose levels underestimate the actual hazards by an order of magnitude. The new dosage response curves indicate that linear extrapolation fails because it disregards the subgroups in the general population that are particularly vulnerable to x-ray. There are immediate implications concerning the use of medical x-rays in screening or for routine purposes. The past risk-benefit calculations are based on extrapolative estimates and require drastic revision. Uses of x-ray which were previously marginal are now clearly counterindicated.
大多数低水平电离辐射暴露，包括诊断性X光和核辐射，都发生在100毫拉德至10拉德的范围内——即“一拉德范围”。过去，该范围内的危害估计是通过从暴露于更高剂量（通常是用于非恶性疾病放射治疗的厘拉德范围）的人员数据进行线性外推得出的。本文展示了首个直接从暴露于普通诊断性辐射的男性数据得出的一拉德范围剂量反应曲线。这些发现基于来自三州调查的约220名非淋巴细胞白血病男性和270多名随机样本对照。新发现表明，以前通过从高剂量水平向低剂量水平外推得出的估计将实际危害低估了一个数量级。新的剂量反应曲线表明线性外推失败，因为它忽略了普通人群中对X光特别敏感的亚组。这对医学X光在筛查或常规用途中的使用有着直接影响。过去的风险效益计算基于外推估计，需要大幅修订。以前处于边缘的X光使用现在显然是禁忌的。
