直肠癌术前固定野容积旋转调强放疗剂量学比较  

Dose comparison between fix-field IMRT and VMAT in pre-operation rectum cancer radiation therapy

作　　者：刘路[1] 王皓[1] 杨瑞杰[1] 王俊杰[1] LIULu WANG Hao YANG Rui-jie WANG Jun-jie(Department of Radiation Oncology ,Peking University Third Hospital, Beijng 100191, P. R. China)

机构地区：[1]北京大学第三医院放射治疗科,北京100191

出　　处：《中华肿瘤防治杂志》2017年第13期921-925,929,共6页Chinese Journal of Cancer Prevention and Treatment

基　　金：国家自然科学基金(81071237)

摘　　要：目的比较5野调强放射治疗(5-field intensity modulated radiotherapy,5F-IMRT)、7野调强放射治疗(7-field intensity modulated radiotherapy,7F-IMRT)和容积旋转调强放射治疗(volumetric modulated arc therapy,VMAT)3种直肠癌术前放疗计划的靶区和危及器官剂量分布。分析各种放疗技术的特点,为临床放疗技术选择提供依据。方法顺序选取北京大学第三医院2016-03-01-2016-05-31收治的10例直肠癌术前放疗患者,分别设计5F-IMRT、7F-IMRT和VMAT计划。比较3组计划靶区和危及器官剂量分布。结果 VMAT的靶区适形性指数(conformity index,CI)优于5F-IMRT和7F-IMRT,7F-IMRT略优于5F-IMRT,CI分别为0.88、0.91和0.92;3种技术HI分别为1.08、1.06和1.08,VMAT比IMRT均匀性稍差,P<0.05。在危及器官剂量中,对于肠道和股骨头,VMAT都增加了低剂量区V_(10)、V_(20),但在中高剂量区V_(30),V_(40)和V_(50)上,受累体积减小;在膀胱剂量中,VMAT技术使得膀胱在低或高剂量受累体积上均低于其他两种技术,7F-IMRT中危及器官剂量介于VMAT和5F-IMRT之间。对于骨髓,VMAT技术30Gy以上体积比较5F-IMRT和7F-IMRT的体积降低,V_(30)(分别为14%、19%和17%)。结论对于直肠癌术前放疗患者,5F-IMRT、7F-IMRT和VMAT均可达到靶区处方剂量要求,靶区的剂量适形性和均匀性都有一定的差异。针对如膀胱、骨髓保护比较重要的患者可以采用VMAT技术减少高剂量的体积以减少放射性损伤,如放射性骨髓抑制;针对如肠道保护比较重要的患者可以选择IMRT技术,减少罹患腹泻等并发症的概率。OBJECTIVE The objective of this study was to compare dose distribution and dose delivery to organs at risk with 5-field intensity modulated radiotherapy （SF-IMRT）, 7-field intensity modulated radiotherapy （TF-IMRT） and volumetric modulated arc therapy（VMAT） in pre-operation rectum cancer radiotherapy,and analyze the characteristic of rectum cancer target and evaluate the outcome of different modalities. This research could provide a reference for selection for treatment modalities in rectum cancer radiotherapy. METHODS To analyze three different kinds of plans include 5-beams, 7-beams and VMAT plan and to compare the DVHs, CI, HI and dose delivery to organs at risk. RESULTS VMAT plans showed better in CI; 7-beams plan was better than 5-beams plan. CI of three types of plans was 0.88,0.91, and 0. 92 respectively. And HI were 1. 08,1. 06 and 1. 08 respectively. Fix-field IMRT was better than VMAT plans in aspect of HI （P^0.05）. There was no significant difference in maximum dose within targ＇ets of three kinds of plans. As to organs at risk,such as bowel and femoral head,VMAT plans increased Vi0 and V20 ,but in high dose volume Vs0 ,V40 and Vs0 ,it has a lower value. The volume of low dose region and high dose region were l essl when com- pared VMAT and fixed-field plans in dose delivery to bladder. VMAT plan decreased the volume delivered above 30 Gy and less than 5-beams and 7-beams plans （14 %, 19 0%, 17 %）. CONCLUSIONS For patients undergoing radiotherapy, 5-beams,7-beams and VMAT could meet the acquirement of clinical treatment. But it also showed that there were many different points in these three modalities. Considering the positions of target and volume,relationship between target and organs at risk. Other parameters such as movement and importance of organs at risk, such as bladder, bone marrow pro- tection in patients, VMAT could be used to reduce the high dose volume and injury such as radioactive bone marrow suppression, if intestinal protection is important for patients IMRT techn

关 键 词：直肠癌 危及器官 调强放射治疗 容积旋转调强放射治疗 

分 类 号：R730.55[医药卫生—肿瘤] R735.37[医药卫生—临床医学]