Ruifrok A C, Mason K A, Hunter N, Thames H D
Department of Experimental Radiotherapy, University of Texas, M. D. Anderson Cancer Center, Houston 77030.
Radiat Res. 1994 Sep;139(3):334-43.
Reactions of the skin of the right thigh of mice were used as an experimental model to test possible changes in the radiosensitivity of mouse skin, as represented by changes in the linear-quadratic (LQ) model parameters alpha and beta, as a function of fractionation interval and overall treatment time. In the first series of experiments, variable numbers of 3-Gy fractions with intervals of 6, 24 or 48 h were applied, followed by top-up doses to increase the skin damage to a level that could be scored. The results showed that mouse skin is more sensitive to 3-Gy fractions applied with 48-h intervals than to 3-Gy fractions applied with 6- or 24-h intervals. In the second series of experiments we used single-dose or fractionated test treatments for previously unirradiated mice and mice treated with priming doses of 10, 20 or 30 Gy given 1-18 days before the test treatment. The sensitivity appeared to be higher after intervals of 14-18 days than after 1-10 days after priming treatments of 20 and 30 Gy. The increased sensitivity 18 days after 20 Gy was mainly the result of an increase in the beta component of the LQ model; higher values of alpha were also determined. We conclude that the radiosensitivity of mouse skin is higher during a radiation-induced proliferative response.
以小鼠右大腿皮肤反应作为实验模型，来测试小鼠皮肤放射敏感性可能发生的变化，这种变化由线性二次（LQ）模型参数α和β的变化表示，它是分次照射间隔时间和总治疗时间的函数。在第一组实验中，应用了不同数量的3Gy分次照射，间隔时间分别为6、24或48小时，随后给予补充剂量以将皮肤损伤增加到可评分的水平。结果表明，小鼠皮肤对间隔48小时给予的3Gy分次照射比间隔6或24小时给予的3Gy分次照射更敏感。在第二组实验中，我们对未接受过照射的小鼠以及在测试治疗前1 - 18天给予10、20或30Gy预照射剂量的小鼠进行了单剂量或分次测试治疗。在20和30Gy预照射治疗后，间隔14 - 18天的敏感性似乎高于间隔1 - 10天的敏感性。20Gy照射18天后敏感性增加主要是LQ模型β成分增加的结果；同时也测定出了更高的α值。我们得出结论，在辐射诱导的增殖反应期间，小鼠皮肤的放射敏感性更高。
