Travis E L, Thames H D, Watkins T L, Kiss I
Department of Experimental Radiotherapy, University of Texas M.D. Anderson Hospital and Tumor Institute, Houston 77030.
Int J Radiat Biol Relat Stud Phys Chem Med. 1987 Dec;52(6):903-19. doi: 10.1080/09553008714552491.
The kinetics of repair of sublethal damage in mouse lung was studied after fractionated doses of 137Cs gamma-rays. A wide range of doses per fraction (1.7-12 Gy) was given with interfraction intervals ranging from 0.5 to 24 h. The data were analysed by a direct method of analysis using the incomplete repair model. The half-time of repair (T1/2) was 0.76 h for the pneumonitis phase of damage (up to 8 months) and 0.65 h for the later phase of damage up to 12 months. The rate of repair was dependent on fraction size for both phases of lung damage and was faster after large dose fractions than after small fractions. The T1/2 was 0.6 h (95 per cent c.1. 0.53, 0.69) for doses per fraction greater than 5 Gy and 0.83 h (95 per cent c.1 0.76, 0.92) for doses per fraction of 2 Gy. Repair was nearly complete by 6 h, at least for the pneumonitis phase of damage. To the extent that extrapolation of these data to humans may be valid, these results imply that treatments with multiple fractions per day that involve the lung will not be limited by the necessity for interfraction intervals much longer than 6 h.
在给予分次剂量的137Csγ射线后，研究了小鼠肺亚致死损伤的修复动力学。每次分次剂量范围较宽（1.7 - 12 Gy），分次间隔时间为0.5至24小时。使用不完全修复模型通过直接分析方法对数据进行分析。损伤的肺炎阶段（长达8个月）修复的半衰期（T1/2）为0.76小时，而长达12个月的损伤后期为0.65小时。肺损伤两个阶段的修复速率均取决于分次剂量大小，大剂量分次后的修复比小剂量分次后更快。对于每次分次剂量大于5 Gy的情况，T1/2为0.6小时（95%置信区间0.53, 0.69），对于每次分次剂量为2 Gy的情况，T1/2为0.83小时（95%置信区间0.76, 0.92）。至少对于损伤的肺炎阶段，修复在6小时时几乎完成。就这些数据外推至人类可能有效的程度而言，这些结果表明，每天多次分次且涉及肺部的治疗不会因分次间隔时间必须远长于6小时而受到限制。
