分次剂量可变方案照射SK-BR-3荷瘤小鼠的实验研究

Research on the Effect of Fractionated Irradiation with Variable Fraction Sizes on the Mice Bearing SK-BR-3 Tumor

目的用人乳腺癌SK-BR-3荷瘤小鼠研究分次剂量可变(VFS)照射方案的效果。方法用6组荷瘤鼠进行实验,其中4组用VFS方案照射,1组用等分次剂量(CFS)方案照射,1组不照射作为肿瘤对照组,分别观察各组小鼠的肿瘤体积变化及存活天数并进行分析比较。结果各照射组的平均存活天数(ASP)均比肿瘤对照组的ASP(25.14d±0.69d)有所延长且有统计学意义。4个VFS方案照射组的ASP都比CFS方案组的ASP(30.80d±6.57d)有所延长,说明VFS方案的照射效果要略好于CFS方案,但统计学处理结果未见差异的显著性。在VFS方案中,剂量递减方案组所获得的荷瘤鼠ASP均略高于其对应的剂量递增方案组,说明剂量递减方案要略好于剂量递增方案,但同样统计学处理结果未见差异的显著性;所有组别荷瘤小鼠的平均体积均随时间增加而增加,其中肿瘤对照组体积增加速度最快。结论照射剂量相同时,与CFS方案相比,VFS方案,尤其是分次剂量递减方案能延长小鼠生存期,因此该类照射方案可以应用于临床以提高治疗效果。

Objective To analyze the effect of fraetionated irradiation with variable fraction sizes（VFS） on the mice bearing SK - BR - 3 tumor. Methods The mice were divided into six groups, four groups were irradiated with different VFS protocols, one group was irradiated with constant fraction size（CFS） protocol, one group was non- irradiated as a comparing group. For these groups of mice, the average surviving period （ASP） and the change of tumor volume were observed and compared. Results The ASP of irradiated groups are all longer than that of non - irradiated group, and the difference of ASP between these groups have the statistical significance respectively. Also the ASP of the groups irradiated with VFS protocols are all longer than that of the group irradiated with CFS protocol, but the difference is of no statistical significance. For the mice irradiated with decreasing fraction sizes, the ASP is longer than that of the mice irradiated with corresponding increasing fraction sizes, but the difference has no statistical significance. For these six groups, the tumor volumes are all increasing in this experiment, and the increasing speed of non - irradiated group is faster than that of all the other irradiated groups. Conclusion For the same absorbed dose, the VFS irradiation protocol, especially the protocol with decreasing fraction sizes can prolong the ASP of mice, so perhaps this kind of protocol can be used in clinics to improve the effect in radiotherapy.