食管癌VMAT与IMRT的剂量学比较  

The application of volumetric modulated arc therapy in esophageal carcinoma

作　　者：刘丽虹[1] 王澜[1] 韩春[1] 张靖[1] 田华[1] 李晓宁[1] 

机构地区：[1]河北医科大学第四医院放疗科,石家庄050011

出　　处：《中华放射肿瘤学杂志》2015年第3期318-322,共5页Chinese Journal of Radiation Oncology

摘　　要：目的 比较食管癌VMAT与静态IMRT的剂量学差异,探索VMAT的可行性.方法 2011-2012年入组食管癌患者30例,颈段、胸下段各5例,胸上段、胸中段各10例.用医科达Oncentra 4.1计划系统分别设计单弧VMAT和IMRT计划,PTV处方剂量60Gy分30次.用Delta 4进行剂量验证.配对t检验或Wilcoxon符号检验比较两组计划PTV、OAR受量、机器跳数及有效治疗时间.结果 两组计划均能满足临床剂量学要求.与IMRT相比VMAT的CI值好（P =0.008）,脊髓Dmax更低（P=0.032）,但心脏V30、V40、Dmean增高（P=0.041、0.012、0.002）;颈段病变VMAT的肺V5-V15及MLD增高（P=0.002-0.022、0.022）;胸上段病变VMAT的心脏V30、Dmwan增高（P=0.030、0.026）,脊髓Dmax减低（P=0.006）;胸中段病变VMAT的肺V10-V20减低（P =0.015-0.041）;胸下段病变两组计划各项指标相近（P=0.262-0.998）.3 mm/3％标准下γ通过率VMAT为92.75％,IMRT为92.98％ （P =0.826）.机器跳数VMAT为460.66 MU,IMRT为522.55 MU,平均减少11.84％ （P =0.001）.有效治疗时间VMAT为139.6 s,IMRT为298.73 s,缩短了53.27％（P=0.000）.结论 在靶区覆盖率相似前提下,VMAT可降低部分OAR受量,并能改善CI值、减少机器跳数、缩短有效治疗时间.Synergy平台上的VMAT计划剂量稳定可靠.Objective To compare the dosimetric difference between volumetric modulated arc therapy （VMAT） and static intensity modulated radiotherapy （IMRT） for esophageal carcinoma.Methods Thirty patients were selected in this study,including 5 cases in the cervical,5 the lower thorax,10 the upper thorax and 10 the middle thorax.VMAT plans with a single arc and IMRT plans with five fields designed for each patients.Planning target volume （PTV） were prescribed to 60 Gy in 30 fractions.Delta 4 was used to verifie the dosimetric of treatment plans.Using paired t-test or Wilcoxon signed-test to compare the dose distribution on planning and organs at risk （OAR）.The monitor units and treatment time were also evaluated to measure the treatment efficiency.Results All the VMAT and IMRT plans can satisfy the clinical dosimetry requirements.VMAT had better conformal index for PTV than IMRT （P =0.008）.VMAT was better than IMRT by reducing the Dmax of spinal cord （P =0.032）,while the V30,V40 and Dmean of heart were significantly higher （P =0.041,0.012,0.002）.For cervicals,the V5,V10,V15 and mean dose of lung were significant higher in VMAT than those in IMRT （P =0.002-O.002,0.002）.For uppers,the values of heart V30 and Dmean were significantly larger in VMAT than IMRT （P =0.030,0.026）.However,the Dmax of spinal cord in VMAT was lower than IMRT （P =0.006）.For middles,VMAT reduced V10,V15,V20 of lung （P =0.015,0.028,0.041）.There were no significant differences between VMAT and IMRT in the lowers （P =0.262-0.998）.The 3 mm/3% γ pass rate was 92.75% for VMAT and 92.98% for IMRT （P =0.826）.The average MU of VMAT （460.66 MU） was reduced by 11.84% compared with IMRT （522.55 MU） （P=0.001）.The delivery time of VMAT （139.6s） compared with IMRT （298.73 s） was reduced by an average of 53.27% （P =0.000）.Conclusions Compared with IMRT,VMAT improved the OARs dose sparing and the target CI with similar dose distribution to the target.VMAT required fewer MU,shorten the treatmen

关 键 词：食管肿瘤/容积调强弧形疗法 食管肿瘤/调强放射疗法 剂量学 γ通过率 

分 类 号：R735.1[医药卫生—肿瘤]