Ang K K, van der Kogel A J, Van Dam J, van der Schueren E
Radiother Oncol. 1984 Jan;1(3):247-53. doi: 10.1016/s0167-8140(84)80007-9.
The kinetics of repair of sublethal damage were investigated in the cervical spinal cord of rats. Two and 4 fractions have been given with intervals ranging from 20 min to 24 h. The occurrence of paralysis within 7 months after irradiation (due to white matter necrosis) was used as the endpoint. From dose-response curves, ED50 values (dose at which 50% of the animals develop paralysis) were determined, from which the proportion of the dose repaired (FR) during the different intervals can be calculated. It was found that the rate of cellular repair of sublethal damage was exponential, with a half-time of approximately 110 min after a fraction size of 11-15 Gy and 85 min after 7-11 Gy. The corresponding time to complete cellular repair was calculated to be 8 and 6 h, respectively. This suggests that the rate of cellular repair is faster after smaller fractions.
在大鼠颈脊髓中研究了亚致死性损伤的修复动力学。给予2次和4次分割照射，间隔时间为20分钟至24小时。将照射后7个月内出现的麻痹（由于白质坏死）作为观察终点。从剂量反应曲线确定ED50值（50%的动物出现麻痹的剂量），由此可以计算出不同间隔期间修复的剂量比例（FR）。结果发现，亚致死性损伤的细胞修复速率呈指数形式，在分次剂量为11 - 15 Gy后，半衰期约为110分钟，7 - 11 Gy后为85分钟。计算得出完成细胞修复的相应时间分别为8小时和6小时。这表明较小分次剂量后的细胞修复速率更快。
