Watanabe H, Okamoto T, Yamada K, Ando Y, Ito A, Hoshi M, Sawada S
Department of Cancer Research, Hiroshima University, Japan.
J Radiat Res. 1993 Sep;34(3):235-9. doi: 10.1269/jrr.34.235.
The effects of the dose rate and the energy of fission neutrons using an iron block on tumorigenesis in B6C3F1 mice were examined. Six-week-old female animals were divided into 4 groups and exposes to 252Cf neutron irradiation at dose rates of 0.05 cGy/min, with (Group 1) or without (Group 2) filtering through a 10 cm thick iron block, 0.8 cGy/min (Group 3) or 0 (Group 4 controls). Total neutron exposure was 50 cGy in each of groups 1-3 and total irradiation dose was 56, 75 and 75 cGy in Groups 1-3, respectively. Total tumor incidences or multiplicity were significantly higher in Group 3 than in Group 1. A similar tendency was observed as compared to Group 2, ovarian and Harderian gland tumors being mainly affected and adrenal tumors were significantly higher in Group 2 than in Group 1. The results indicated a clear increase in tumorigenesis with the higher dose rate and no filtering influence of iron was evident, despite the drop in neutron energy level.
研究了使用铁块时裂变中子的剂量率和能量对B6C3F1小鼠肿瘤发生的影响。将六周龄雌性动物分为4组，分别以0.05 cGy/分钟的剂量率接受252Cf中子照射，其中一组（第1组）通过10厘米厚的铁块过滤，另一组（第2组）不经过铁块过滤，第3组剂量率为0.8 cGy/分钟，第4组（对照组）剂量率为0。第1 - 3组的总中子暴露量均为50 cGy，第1 - 3组的总照射剂量分别为56、75和75 cGy。第3组的总肿瘤发生率或肿瘤多发性显著高于第1组。与第2组相比也观察到类似趋势，主要受影响的是卵巢和哈德氏腺肿瘤，第2组的肾上腺肿瘤显著高于第1组。结果表明，尽管中子能量水平下降，但随着剂量率升高，肿瘤发生明显增加，且铁块没有明显的过滤影响。
