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目的探讨合适的全身照射时间-剂量分割模式.方法健康成年SD大鼠45只随机分为Ⅰ组8Gy(单次照射)、Ⅱ组4Gy×2(总剂量分2次照射,间隔时间6h)、Ⅲ组12Gy(单次照射)、Ⅳ组2Gy×2×3(总剂量分6次照射,每天照射2次,间隔时间6h,连续照射3d)、空白对照组.模拟人全身放疗照射技术,采用6MV X射线全身照射,剂量率10cGy/min,分别于照射后第1天和第14天取大鼠肺组织采用免疫组织化学染色法,分析TGF-β1蛋白在肺组织中的表达,比较不同分割照射方式放射性肺损伤程度;全身照射后2周取大鼠肝肾组织常规HE染色观察放射损伤病理组织学变化,血生化分析仪测定大鼠肝功能指标ALT、肾功能指标BUN.结果照射后第1天及14天大鼠肺组织TGF-β1蛋白免疫组化染色,TGF-β1蛋白在肺组织中的表达水平照射后第1天,8Gy组与4Gy×2组无显著差异(P>0.05),其余各组显示分次照射较相同剂量下的单次照射表达水平低(P0.05).各TBI照射组肝功能指标ALT、肾功能指标BUN与对照组无显著差异(P>0.05),观察期间肝脏、肾脏病理组织学变化较轻.结论全身放疗采用分次照射模式可以适当增加照射剂量,保护正常组织特别是肺组织的放射损伤.“,”Objective To investigate appropriate time-dose fraction in TBI.Methods 45 maturity Sprague-Dawley rats were randomly divided into 5 groups:8Gy group(single fraction irradiation);4Gy×2 group(twice fraction irradiation,interval time 6 hours);12Gy group(single fraction irradiation);2Gy×2×3 group(six fraction irradiation,twice everyday,interval time 6 hours);blank control group.The TBI group rats were irradiated by 6MV X ray of electric linear accelerator using a 10cGy/min dose rate.Immunohistochemical method was used to detect the expression of TGF-β1 protein in lung on the first day and fourteenth day after TBI and analyze the radiation-induced lung injury of different time-dose-fraction radiation.ALT and BUN was detected to analyze the hepatic function and renal function of rats after TBI to observe the pathohistology of radiation injury of liver and kidney by HE stain.Results Immunohistochemical expression level of TGF-β1 protein on the first day and fourteenth day after TBI showed significant difference in STBI and FTBI and expression level of TGF-β1 protein was low in FTBI compared with STBI in identical irradiation dose except 8Gy group and 4Gy×2 group on the first day. ALT an BUN have no significant diversity compared with blank control group.Pathohistology of irradiation injury of liver and kidney were not obvious.Conclusion Total dose can be increased in proper extent through adopting FTBI pattern,while radiation-induced injury of normal tissue especially lung can be lessened.