Tumor induction in BALB/c mice after fractionated or protracted exposures to fission-spectrum neutrons.
Tumor induction in BALB/c mice after fractionated or protracted exposures to fission-spectrum neutrons.
复制标题
BALB/c 小鼠在分次或长时间暴露于裂变谱中子后诱导肿瘤。
作者：
R. Ullrich
本研究研究了剂量率或分割对裂变中子致癌作用的影响，重点是低于 50 拉德的剂量范围。在以高剂量率单次照射进行全身中子照射后，或以间隔 24 小时或 30 天的两个等份进行全身中子照射后，检查雌性 BALB/c 小鼠肺腺癌、乳腺癌和卵巢肿瘤的诱导情况，并将这些效果与低剂量率中子照射后的效果进行比较。分次剂量分割方案后卵巢肿瘤发生的剂量反应与单次高剂量率中子暴露后观察到的相似。然而，降低剂量率可降低 0-50 rad 剂量范围内的发生率。对于肺癌和乳腺肿瘤，结果更为复杂。这些数据表明，对于不同的肿瘤类型，分割和剂量率效应是不同的，可能是因为可能涉及不同的肿瘤发生机制。
This study has examined the effect of dose rate or fractionation on the carcinogenic effects of fission neutrons with emphasis on the dose range below 50 rad. The induction of lung adenocarcinomas, mammary adenocarcinomas, and ovarian tumors in female BALB/c mice was examined after whole-body neutron irradiation delivered at a high dose rate as a single exposure, or delivered as two equal fractions separated by intervals of 24 hr or 30 days and compared these effects to those after neutron irradiation at low dose rates. The dose responses for ovarian tumorigenesis after the split-dose fractionation regimen were similar to that observed after single high-dose-rate neutron exposure. However, lowering the dose rate reduced the incidence over the dose range of 0-50 rad. For lung and mammary tumors the results were more complex. These data suggest that fractionation and dose-rate effects are different for different tumor types presumably because of the different mechanisms of tumorigenesis that may be involved.