Terry N H, Ang K K, Hunter N R, Milas L
Department of Experimental Radiotherapy, University of Texas, M. D. Anderson Hospital & Tumor Institute, Houston 77030.
Radiat Res. 1988 Jun;114(3):621-6.
These experiments were designed to study the kinetics and magnitude of cell repair and repopulation in tissues whose damage results in the tumor bed effect. The right hind thighs of mice were irradiated with single doses or two equal gamma-ray fractions. Interfraction intervals ranging from 30 min to 24 h (to measure the kinetics of repair from sublethal damage) and 6 and 12 weeks (to determine the extent of repopulation) were used. One day after the second radiation dose 5 X 10(5) FSA tumor cells were inoculated into the center of the irradiated field. Radiation dose-response curves were obtained by calculating the time required for tumors to reach 12 mm diameter. No recovery occurred within 6 h of the radiation delivery as measured by this assay. Some recovery, 3.2-4.6 Gy above a single radiation dose, occurred when the interval between two fractions was 24 h. With increasing interfraction intervals of 6 and 12 weeks further dose sparing occurred in the amount of 5.0-6.9 and 7.5-8.3 Gy, respectively. The data suggest that repopulation is the major contributor to the radiation dose-sparing recovery of stromal tissue and that some proliferative response may occur as early as 1 day after the first irradiation.
这些实验旨在研究因损伤导致瘤床效应的组织中细胞修复和再增殖的动力学及程度。对小鼠的右后大腿进行单次剂量或两个相等剂量的γ射线照射。使用了30分钟至24小时的分次照射间隔（以测量亚致死损伤的修复动力学）以及6周和12周的间隔（以确定再增殖程度）。在第二次辐射剂量后一天，将5×10(5)个FSA肿瘤细胞接种到照射区域的中心。通过计算肿瘤达到12毫米直径所需的时间来获得辐射剂量反应曲线。通过该测定法测量，在辐射后6小时内未发生恢复。当两个分次之间的间隔为24小时时，出现了一些恢复，比单次辐射剂量高3.2 - 4.6 Gy。随着分次间隔增加到6周和12周，分别进一步出现了5.0 - 6.9 Gy和7.5 - 8.3 Gy的剂量节省。数据表明，再增殖是基质组织辐射剂量节省恢复的主要因素，并且在首次照射后1天可能就会出现一些增殖反应。
