鼻咽癌调强放射治疗后放射诱发肿瘤发生风险的预测分析  

Predicted risk of radiation-induced malignancy after intensity-modulated radiotherapy for nasopharyngeal carcinoma

作　　者：习勉[1] 梁健[1] 孙文钊[1] 邓小武[1] 刘孟忠[1] 张黎[1] 

机构地区：[1]华南肿瘤学国家重点实验室/中山大学肿瘤防治中心放射治疗科,广东广州510060

出　　处：《中国医学物理学杂志》2016年第1期6-9,共4页Chinese Journal of Medical Physics

基　　金：国家自然科学基金(81201748);广东省科技计划项目(2012B061700083)

摘　　要：目的:比较分析鼻咽癌常规放疗与调强放射治疗(IMRT)时正常器官的等效剂量,预测鼻咽癌放疗后放射诱发肿瘤(RIM)的发病风险。方法:选择80例鼻咽癌患者的影像资料,在Monaco治疗计划系统为每例患者模拟两套放疗计划:常规二维放疗与IMRT。采用蒙特卡罗算法计算照射野内正常器官的吸收剂量;将治疗计划传输至直线加速器,把射野移植到拟人验证模体,使用热释光剂量探测仪测量射野外正常器官的散射剂量。综合分析不同放疗技术条件下各正常器官的等效剂量,与辐射致癌风险预测系数相结合,计算RIM发生风险值。结果:根据ICRP辐射致癌风险预测系数,结合各器官的平均等效剂量数据,鼻咽癌IMRT治疗后的全身各器官RIM的总发生风险为10.2%,显著高于常规放疗的5.9%,是后者的1.73倍(P=0.007)。结论:鼻咽癌IMRT治疗后各器官RIM的总发生风险预测值显著高于常规放疗,需要引起临床重视。Objective To compare and analyze the equivalent dose of normal organs in intensity-modulated radiotherapy （IMRT） and conventional two-dimensional radiotherapy （2DRT） for nasopharyngeal carcinoma （NPC）; to predict the risk of radiation- induced malignancies （RIM） after radiotherapy. Methods Imaging data of 80 NPC patients were selected; both 2DRT and IMRT plans were designed for each patient in Monaco treatment planning system. The absorbed doses of normal organs in radiation fields were determined by using Monte Carlo calculations. The treatment plans were transferred into linear accelerator, and the radiation fields were moved into humanoid phantom. The dispersion doses of normal organs outside the fields were determined by using thermoluminescent dosimeter measurements. The predicted RIM risks were calculated by comprehensively analyzing the equivalent dose of normal organs under different radiotherapy conditions and RIM risk prediction coefficients. Results According to RIM risk prediction coefficients and the mean equivalent dose of normal organs, the total RIM risks of organs were respectively 10.2%, 5.9% in IMRT and 2DRT for NPC. The total risk of IMRT plan was 1.73 times that of 2DRT. Conclusion The predicted total RIM risk of IMRT for NPC is significantly higher than that of 2DRT, which should arouse clinical attention.

关 键 词：鼻咽癌 调强放射治疗 常规二维放疗 放射诱发肿瘤 

分 类 号：R739.63[医药卫生—肿瘤]