Thomson J F, Grahn D
Biological, Environmental, and Medical Research Division, Argonne National Laboratory, Illinois 60439-4833.
Radiat Res. 1989 Apr;118(1):151-60.
Data are presented on the mean aftersurvival of male B6CF1 mice exposed for 22 h per day, 5 days per week, to 60Co gamma radiation at dose rates of 1.36 to 12.64 x 10(-3) cGy/min for 23 weeks or 1.36 to 6.32 x 10(-3) cGy/min for 59 weeks. For deaths from all causes, linear dose-response curves were obtained with slopes (days of life lost/cGy) of 0.158 +/- 0.016 and 0.077 +/- 0.002 for 23- and 59-week exposures, respectively. These values were not significantly altered when the analysis was restricted to those mice dying with tumors (92% of the total) or to those presumably dying from tumors (82% of the total). Analysis of mortality rates showed that about 90% of the radiation-specific excess mortality was tumor related. The 59-week exposure series induced only a small increase in the number of days of life lost/cGy/weekly fraction over that induced by 23 weeks of irradiation, 4.53 +/- 0.15 compared to 3.64 +/- 0.36 days lost/cGy/weekly fraction. This lower than expected value for 59 weeks of exposure may signal the approach to the final linear, additive, injury term postulated from earlier studies at this laboratory with low-dose-rate, daily, duration-of-life 60Co gamma irradiation.
本文呈现了雄性B6CF1小鼠的平均存活时间数据。这些小鼠每周5天，每天暴露于60Co伽马辐射下22小时，剂量率为1.36至12.64×10(-3) cGy/分钟，持续23周；或剂量率为1.36至6.32×10(-3) cGy/分钟，持续59周。对于所有原因导致的死亡，获得了线性剂量反应曲线，23周和59周暴露的斜率（寿命损失天数/cGy）分别为0.158±0.016和0.077±0.002。当分析仅限于死于肿瘤的小鼠（占总数的92%）或可能死于肿瘤的小鼠（占总数的82%）时，这些值没有显著变化。死亡率分析表明，约90%的辐射特异性额外死亡率与肿瘤相关。与23周照射相比，59周暴露系列仅使每cGy/每周剂量组的寿命损失天数略有增加，分别为4.53±0.15天和3.64±0.36天。59周暴露的这一低于预期的值可能表明接近本实验室早期低剂量率、每日、终生60Co伽马照射研究中假设的最终线性、累加损伤项。
