鼻咽癌调强放疗靶区安全外扩边界研究  

Research on the safety target margin in intensity-modulated radiation therapy of nasopharyngeal carcinoma

作　　者：李志聪[1] 李陆军[1] 向昭雄 游雁[1] 余海坤[1] 李业居 韦天有 钟宇行 宁金标 

机构地区：[1]梧州市红十字会医院放疗科,广西梧州543002

出　　处：《现代肿瘤医学》2017年第21期3513-3515,共3页Journal of Modern Oncology

基　　金：梧州市科学研究与技术开发计划项目(编号:2014E01070;201402017)

摘　　要：目的:利用电子射野影像验证系统(electronic portal imaging device,EPID)监测鼻咽癌调强放疗的摆位误差为PTV外扩边界提供依据,使得放射治疗计划的设计更为科学合理。方法:随机选取50例鼻咽癌调强放疗患者,采用"盲拍"模式获取患者治疗前及每周的摆位误差结果,根据公式MPTV=2.5Σ+0.7σ计算CTV到PTV外扩边界。结果:在左右、上下和前后各方向的误差分别为(0.004 6±0.087 5)cm,(0.048 3±0.065 1)cm和(0.027 2±0.137 3)cm;得到左右、上下和前后方向上外扩的边界分别为0.1 cm、0.4 cm、和0.4 cm。结论:通过图像引导方式监测患者的摆位误差情况,可以评估靶区安全的外扩边界。为保证肿瘤区域得到准确的剂量和减少正常组织受量,PTV外扩边界理论上应不小于0.4 cm。Objective：To investigate setup error during intensity modulated radiation therapy （IMRT） for naso- pharyngeal carcinoma and provide the basis for margin of planning target volume（PTV） by EPID（ electronic portal imaging device） , and to insure the radiation treatment planning more scientific and reasonable. Methods：Fifty NPC patients were enrolled in this study,whose electronic portal images were acquired by ＂ blind＂ mode before treat- ment and weekly. The data can be used to calculate the margin from CTV to PTV according to the formula MPTV = 2.5E ± 2.5ty. Results：The average setup error of NPC patients＇were （0.004 6 ±0. 087 5） cm in left - right di- rection, （0.048 3 ± 0. 065 1 ） cm in superior - inferior direction and （0. 027 2 ± 0. 137 3 ） cm in anterior - posterior direction. The target margin were 0.1 em in left - right direction,0.4 cm in superior - inferior and anterior - posterior direction. Conclusion：The data of patients setup error by the way of image guided can be used for estimating the safe- ty target margin. In order to ensure the patients＇target totally irradiated and protect the more normal tissue to avoid un- necessary irradiation, the PTV expanding boundary should not be less than 0.4 cm in theory.

关 键 词：调强放疗 摆位误差 边界 

分 类 号：R739.63[医药卫生—肿瘤]