鼠脑胶质瘤近距离放疗的实验研究

Brachytherapy of rat glioma

目的 :探讨铱 192间质放疗 ,不同剂量分割对实验性鼠脑胶质瘤的影响。方法 :选用种植胶质瘤 17只 SD鼠进行 0～ 10 0 0 c Gy/ 2次 /天的分割剂量放疗 ,比较 15 0～ 30 0 c Gy组和 5 0 0～ 10 0 0 c Gy组放疗过程中的影像变化 ,模式特征和生存期。结果 :5 0 0～ 10 0 0 c Gy组瘤体出现中央坏死率为 10 0 % (4 / 4) ,15 0～ 30 0 c Gy组为 2 2 .2 % (2 / 9) ,两组相比 P<0 .0 5。治疗中瘤体中央无坏死组 (n=7)的体积平均缩小率为 76 .4% ,瘤体中央有坏死组 (n=6 )缩小率为 2 .3% (P<0 .0 1) ,放疗结束二者分别为 80 .1%和 37.8% ,有显著性差异 (P<0 .0 5 )。放疗死亡鼠的平均生存期为 2 7天 (n=8) ,高于对照组鼠平均生存 7天 (n=3) ,P<0 .0 5。放疗结束 1个月 15 0～ 30 0 c Gy组的生存率为 80 %(8/ 10 ) ,5 0 0～ 10 0 0 c Gy组全部死亡 ,P<0 .0 1。结论 :15 0～ 30 0 c Gy组肿瘤以体积缩小为主 ,5 0 0～ 10 0 0 c Gy组以中央坏死为主 ,前者体积缩小更明显 。

Objective:To investigate the effect of 192 Ir brachytherapy in a rat glioma model with different radiation doses.Methods:Six treatment groups and one control group of 17 rats bearing brain gliomas were treated in a dose range of 0～1000cGy/2/per day with emphasis on imaging changes,phantom characteristics as well as life span in 150～300cGy and 500～1000cGy groups.Results:The central necrosis occurred in 500～1000cGy group (100%,4/4),significantly higher than 150～300cGy group(22.2%,2/9,P<0 05).The decrease of tumor volume in tumors without central necrosis(n=7) were more obvious than that of tumors with central necrosis(n=6),respectively(76.4% vs 2.3%,P<0 01 and 80.1% vs 37.8%,P<0 05).The life span of dead group(n=8)with brachytherapy(n=8)was greater than that of group(n=3)without brachytherapy(average day 27 vs 7,P<0.05).The Survival rate of 150～300 groups l month after brachgtherapy were greater tha that of 500～1000group(80%vs 0%,P<0.01).Conclusion:The greater continuously decreases of tumor volumes occurred frequently in dose group range of 150～300cGy groups which produced significant increase in survival,whereas central necrosis were founded much more in dese of 500～1000cGy groups.