直肠癌术后固定剂量率容积调强放射治疗的初步研究  

Preliminary study on fixed dose rate volumetric modulated intensity radiotherapy in postoperative patients with rectal cancer

作　　者：陈祥 周剑良[1] 王彬冰[2] 李浦[2] 单国平[2] CHEN Xiang;ZHOU Jianliang;WANG Binbing;LI Pu;SHAN Guoping(Department of Nuclear Science and Technolory,University of South China,Hengyang 421001,China;Department of Radiotherapy Physics/Key Laboratory of Tumor Radiation Therapy,Zhejiang Cancer Hospital)

机构地区：[1]南华大学核科学技术学院,衡阳421001 [2]浙江省肿瘤医院放射物理室浙江省肿瘤放射治疗重点实验室

出　　处：《实用肿瘤学杂志》2018年第4期327-332,共6页Practical Oncology Journal

基　　金：基于大数据和人工智能的远程放疗服务模式研究(编号:2017YFC0113201)

摘　　要：目的初步探讨固定剂量率容积调强在直肠癌术后盆腔放射治疗中的可行性。方法选取10例直肠癌放疗患者,利用Ray Station计划系统为每例患者制定可变剂量率容积调强(VDR-VMAT)、固定剂量率容积调强(CDR-VMAT)和5野静态调强(5F-s IMRT)计划。运用剂量体积直方图评估三种计划的靶区、危及器官和正常组织剂量学参数,评估机器总跳数(MU)和计划执行时间。结果靶区剂量方面,三种计划的靶区D2%、D_(mean)、D98%、HI和CI在总体上均有差异(P<0.001)。CDR-VMAT与VDR-VMAT相比较,D2%、D_(mean)、D98%、HI、CI差异均无统计学意义;CDR-VMAT与5F-s IMRT相比较,D2%减小1.55 Gy(P=0.005)、D_(mean)减小0.99 Gy(P=0.005)、D98%增大0.60 Gy(P=0.03)、HI值减小(P=0.008)、CI值增大(P=0.008)。危及器官方面,三种计划的膀胱D_(mean)、V_(45)、V_(40),小肠D_(mean)、Dmax、V_(45),左右股骨头D_(mean)在总体上均有差异(P<0.05);小肠V_(40)、V_(35),左右股骨头V_(45)、V_(40)在总体上均无差异(P>0.05)。CDR-VMAT与VDR-VMAT相比较,膀胱、小肠、左右股骨头的各剂量学参数差异无统计学意义;CDR-VMAT与5F-s IMRT相比较,膀胱D_(mean)减小3.05Gy(P=0.005)、V_(40)减小0.88%(P=0.042),小肠D_(mean)减小1.75 Gy(P=0.002)、Dmax减小1.70 Gy(P<0.001),左、右股骨头D_(mean)减小(P=0.008,0.042)。正常组织低剂量受照体积方面,三种计划的正常组织受照低剂量体积除V_(10)(P=0.497)之外,V_5、V_(15)、V_(20)、V_(25)和V_(30)在总体上均有差异(P<0.001)。CDR-VMAT与VDR-VMAT相比,V_5、V_(10)、V_(15)、V_(20)、V_(25)和V_(30)差异无统计学意义;与5F-s IMRT相比,CDR-VMAT的V_5减小1.18%(P=0.005)、V_(15)减小0.61%(P=0.022)、V_(30)减小0.80%(P=0.022),V_(10)、V_(20)和V_(25)差异无统计学意义。CDR-VMAT计划的MU为(668.51±45.92),比VDR-VMAT(574.13±50.20)增加16.44%,比5F-s IMRT(537.19±37.34)增加24.45%;CDR-VMAT计划执行时间(3.34±0.22)min是VDR-VMAT(1.76±0.04)min的近两倍,比5F-s IMRT(4~6)min�Objective The objective of this study was to investigate the feasibility of fixed dose rate volumetric modulation in pelvic radiotherapy after rectal cancer surgery. Methods Ten patients with rectal cancer radiotherapy were enrolled in this study. The Ray Station planning system was used to establish a variable dose rate volumetric modulation（ VDR-VMAT）,a fixed dose rate volume modulation（ CDR-VMAT）,and a 5-field static intensity modulated radiation therapy（ 5 F-s IMRT） plans for each patient. Dose volume histograms were used to evaluate the dosimetric parameters of the three planned target area,endangered organs and normal tissue,and to assess the total machine hop count（ MU） and planned execution time. Results In terms of target area dose,CDR-VMAT compared to VDR-VMAT,D2%,D（mean）,D98%,HI and CI were similar; CDR-VMAT compared to 5 F-s IMRT D2%,D（mean）,D98%,HI and CI all had statistically significant differences（ P〈0. 05）. In the aspect of OARs,CDR-VMAT compared with VDR-VMAT,all parameters of bladder,small intestine,left and right femoral head were similar; CDR-VMAT compared with 5 F-s IMRT,D（mean）,V（40） of the bladder,D（mean）,Dmaxof the small intestine,D（mean）of the left and right femoral head all had statistically significant differences（ P〈0. 05）. For the normal tissue,CDR-VMAT compared with VDR-VMAT,V5,V（10）,V15,V（20）,V（25） and V（30）,were similar;CDR-VMAT compared with 5 F-s IMRT,V5,V15 and V（30） all had statistically significant differences（ P〈0. 05）. The MU of the CDR-VMAT plan was 16. 44% higher than that of VDR-VMAT and 24. 45% higher than that of 5 F-s IMRT. The execution time of the CDR-VMAT plan was nearly double than that of VDR-VMAT but shorter than that of 5 F-s IMRT. Conclusion CDR-VMAT can form a high quality plan as VDR-VMAT with better target coverage,endangering organ protection and low dose exposure volume of normal tissue than 5 F-s IMRT. However,the CDR-VMAT plan has more MU than VDR-VMAT and 5 F-s IMRT. The exec

关 键 词：直肠癌 容积调强 静态调强 可变剂量率 固定剂量率 

分 类 号：R735.37[医药卫生—肿瘤]