直接机器参数优化模式下不同子野数目对宫颈癌调强计划的影响  

Influence of beam segment numbers on intensity-modulated radiotherapy for cervical cancer in direct machine parameter optimization

作　　者：王琳婧[1] 张国前[1] 雷怀宇 李慧君[1] 周露[1] 张书旭[1] 

机构地区：[1]广州医科大学附属肿瘤医院放疗中心,广东广州510095

出　　处：《中国医学物理学杂志》2017年第7期708-711,共4页Chinese Journal of Medical Physics

基　　金：广东省教育厅特色创新项目(2016KTSCX116);广东省医药科学技术研究基金项目(A2017349)

摘　　要：目的:比较基于直接机器参数优化模式(DMPO)下3种不同子野数的宫颈癌调强放疗计划的靶区和危及器官的剂量学差异。方法:选取12例I~Ⅲ期宫颈鳞癌患者,采用Pinnacle^(3)9.10放疗计划系统制定7野调强放疗计划,分别设置子野数目为49、35和21个,比较3种不同计划的剂量体积直方图,分析靶区和危及器官受照剂量的差异。结果:较其他两组,49子野组的靶区平均剂量(D_(mean))、D95较高,靶区最大剂量降低,差异均有统计学意义(P<0.05);49子野组的膀胱V_(50),直肠V_(50)、D_(mean)和股骨头V_(30)、D_(mean)均降低,差异有统计学意义(P<0.05)。各组靶区均匀指数和适形指数比较均无统计学意义(P>0.05)。结论:在DMPO下,子野数的适当增多能较好地提高靶区剂量,降低危及器官的受照剂量。Objective To discuss the dosimetric differences of target areas and organs-at-risk（OAR） in cervical cancer patients among 3 intensity-modulated radiotherapy（IMRT） plans with different beam segment numbers based on direct machine parameter optimization（DMPO）. Methods Twelve patents with cervical squamous cell cancer at the stage of I-Ⅲ were selected. Three 7-field IMRT plans with 49, 35 and 21 beam segments were obtained with Pinnacle^（3） 9.10 treatment planning system. The dosevolume histogram, and the dose of target areas and OAR were analyzed among the three plans. Results For the dose of target areas, compared with the other two IMRT plans, the IMRT plan with 49 beam segments showed higher mean dose（D_（mean）） and D_（95） in target areas, and lower maximum dose in target areas, with statistical differences（P0.05）. For OAR dose, the bladder V_（50）,the rectum V_（50） and D_（mean）, and the femoral head V_（30） and D_（mean）were significantly lower in IMRT plans with 49 beam segments,compared with those in the other two groups（P0.05）. No statistical differences were observed in conformal index and homogeneity index of target areas among 3 plans（P0.05）. Conclusion The IMRT plans with properly more beam segment numbers in DMPO can achieve higher dose in target areas and lower OAR dose.

关 键 词：宫颈癌 直接机器参数优化模式 剂量学差异 调强计划 子野数量 

分 类 号：R811.1[医药卫生—放射医学]