Ullrich R L
Radiat Res. 1983 Mar;93(3):506-15.
This study was designed to examine the dose-response relationships for tumor induction after neutron irradiation in female BALB/c mice, with emphasis on the response in the dose range 0 to 50 rad. Tumors induced after radiation exposure included ovarian tumors, lung adenocarcinomas, and mammary adenocarcinomas. For comparison the dose responses for induction of these tumors after 137Cs gamma irradiation were also examined. As previously described for the female RFM mouse, the data for ovarian tumor induction after neutron and gamma irradiation were consistent with a threshold model. For lung and mammary tumors the dose-response curve after neutron irradiation appeared to "bend over" in the dose range 10 to 20 rad. The factors responsible for this bend-over and their relative contributions to the overall form of the dose-response relationship are not presently known. However, these data strongly indicate that extrapolation from data above 50 rad could result in a significant underestimate of risks. Further, it is clear that current models of neutron carcinogenesis are inadequate, since such a bend-over is not predicted at these low dose levels.
本研究旨在探讨雌性BALB/c小鼠经中子照射后肿瘤诱发的剂量-反应关系，重点关注0至50拉德剂量范围内的反应。辐射暴露后诱发的肿瘤包括卵巢肿瘤、肺腺癌和乳腺腺癌。为作比较，还研究了137Csγ射线照射后这些肿瘤诱发的剂量反应。如先前针对雌性RFM小鼠所描述的，中子和γ射线照射后卵巢肿瘤诱发的数据与阈值模型一致。对于肺和乳腺肿瘤，中子照射后的剂量-反应曲线在10至20拉德剂量范围内似乎出现“转折”。目前尚不清楚导致这种转折的因素及其对剂量-反应关系总体形式的相对贡献。然而，这些数据强烈表明，从50拉德以上的数据进行外推可能会导致对风险的显著低估。此外，很明显目前的中子致癌模型并不充分，因为在这些低剂量水平下并未预测到这种转折。
