Oghiso Yoichi, Yamada Yutaka
Internal Radiation Effects Research Group, Research Center for Radiation Safety, National Institute of Radiological Sciences, Japan.
J Radiat Res. 2003 Sep;44(3):261-70. doi: 10.1269/jrr.44.261.
Radiation-induced pulmonary carcinogenesis was compared in female Wistar rats following either inhalation exposure to alpha-emitting (239)PuO(2) aerosols, whole-body or thoracic X-ray irradiation. Dose-dependent survival reduction was correlated with increased malignant lung tumors at doses over 0.45 Gy, reaching the maximum incidence of 90% at 6.6-8.5 Gy in (239)Pu-exposed rats. While the differential dose responses for each histopathological type of tumors were noted, almost 70-80% were carcinomas among all of the primary tumors from (239)Pu-exposed rats. As the dose response curves for lung carcinomas were compared, the slope of the fit linear equation and the calculated relative effectiveness for 50% incidence of lung carcinomas were approximately 11-times as high in (239)Pu-exposure as those of thoracic X-irradiation. The numbers of tumor lesions distributed in the lung per tumor-bearing animal were about 2-fold more in (239)Pu-exposed rats, while the proportions of their histopathological types were similar between (239)Pu-exposure and X-irradiation. These results indicate that the magnitudes of the relative effectiveness or risk for pulmonary carcinogenesis are greater in (239)Pu-exposure than X-irradiation, and that radiation-induced lung tumors appear to originate mostly from the same target epithelial cells.
在雌性Wistar大鼠中，比较了吸入α发射性（239）PuO₂气溶胶、全身或胸部X射线照射后辐射诱发的肺癌发生情况。在剂量超过0.45 Gy时，剂量依赖性存活降低与恶性肺肿瘤增加相关，在暴露于（239）Pu的大鼠中，在6.6 - 8.5 Gy时达到最高发病率90%。虽然注意到每种组织病理学类型肿瘤的剂量反应差异，但在暴露于（239）Pu的大鼠的所有原发性肿瘤中，几乎70 - 80%为癌。比较肺癌的剂量反应曲线时，拟合线性方程的斜率以及计算得出的肺癌发生率为50%时的相对有效性，在暴露于（239）Pu的大鼠中约为胸部X射线照射的11倍。在每只患肿瘤动物的肺中分布的肿瘤病灶数量，在暴露于（239）Pu的大鼠中约多2倍，而它们的组织病理学类型比例在暴露于（239）Pu和X射线照射之间相似。这些结果表明，暴露于（239）Pu时诱发肺癌的相对有效性或风险程度比X射线照射更大，并且辐射诱发的肺肿瘤似乎大多起源于相同的靶上皮细胞。
