摘要
目的 探讨螺旋断层放疗(helical tomotherapy,HT)用于胸中下段食管癌的最优计划参数,初步制定治疗规范.方法 搜集2016年1月到2018年8月接受HT的18例胸中下段食管鳞癌病例,统计各例放疗计划的靶区(PTV)和危及器官(OAR)的剂量分布、剂量学参数、单次治疗时间、机器跳数(MU);记录全部540次摆位误差数据,包括3例154次修正前后的摆位误差数据;分析18次计划剂量验证结果,包括点绝对剂量偏差及γ通过率;利用M=2.5Σ+0.7δ计算靶区边界外扩值;对18例患者分别制作调强放疗(IMRT)和容积旋转调强放疗(VMAT)计划,与HT计划进行多参数比较;抽取3例进行不同射野宽度(FW)和螺距(pitch)组合的HT计划设计,确定最优计划参数;应用SPSS22.0统计软件进行分析.结果 热塑体模组和真空负压垫组摆位误差在左右(X)、头脚(Y)、前后(Z)和横断面上的旋转(Rol)分别为(1.71±1.62)mm、(1.21±1.28)mm、(1.18±1.41)mm、(0.55±1.02)°和(1.68±1.71)mm、(1.23±1.57)mm、(1.22±1.31)mm、(0.73±1.21)°,对应的靶区外扩值在X、Y、Z分别为5.41mm、3.92mm、3.94mm和5.40mm、4.13mm、3.97mm.3例在线修正前后的摆位误差在X、Y、Z和Rol分别为(1.63±1.59)mm、(1.25±1.33)mm、(1.19±1.29)mm、(0.61±1.12)°和(0.61±0.41)mm、(0.52±0.49)mm、(0.43±0.52)mm、(0.51±0.52)°,对应的靶区外扩边界值分别为5.19mm、4.06mm、3.76mm和1.81mm、1.64mm、1.44mm.计划剂量验证的点绝对剂量偏差平均值为(0.14±1.54)%,γ通过率平均值为(95.47±2.35)%.HT与IMRT和VMAT相比,在PTV、脊髓、心脏、肺的最大剂量和肺的V20、V30上具有优势(H=10.786、14.028、7.433、11.403、7.138、6.847,P=0.006、0.001、0.024、0.003、0.028、0.049),但是在PTV均匀性、适形性、危及器官平均剂量、治疗时间、MU上差异不具有统计学意义.HT最优计划参数设置为:FW=2.5cm、Pitch=0.287、调制因子(MF)=2.7.结论 HT与IMRT、VMAT相比优势在于降低靶区及危及器官的最大剂量�
Objective To optimize the planning parameters of helical tomotherapy(HT)for patients with middle-or lower-theoracic esophageal cancer.Methods Eighteen patients with middle-or lower-theoracic esophageal cancer treated by HT in Zhejiang Cancer Hospital during January 2016 to August 2018 were enrolled in this study.The dose distribution of the planning target volume(PTV)and the organ at risk(OAR),dosimetry parameters,single treatment time,machine number(MU)of each radiotherapy plan were calculated.The data of 540 setup errors were recorded,including 3 cases with 154 setup errors before and after correction.The results of 18 patient plan verifications were analyzed,including single point absolute dose deviation andγpass rate.PTV margin was calculated by the formula of M=2.5Σ+0.7δ.Intensity modulated radiation therapy(IMRT)and volume modulated arc therapy(VMAT)plans were made for all of the case,and multiple parameters were compared with HT plans.Three cases were selected for HT planning design with different field width(FW)and pitch,and the optimal planning parameters were determined.Statistical analysis was performed with SPSS22 software.Results The setup errors of thermoplastic body membrane group and vacuum negative pressure pad group in directions of left-right(X),cranial-caudal(Y),anterior-posterior(Z)and Roll were(1.71±1.62)mm,(1.21±1.28)mm,(1.18±1.41)mm,(0.55±1.02)°and(1.68±1.71)mm,(1.23±1.57)mm,(1.22±1.31)mm,(0.73±1.21)°,respectively.The corresponding PTV margin values were 5.19mm,4.06mm 3.76mm and 1.81mm,1.64mm,1.44mm,respectively.Three cases of setup errors before and after online correction in X,Y,Z and Roll were(1.63±1.59)mm,(1.25±1.33)mm,(1.19±1.29)mm,(0.61±1.12)°and(0.61±0.41)mm,(0.52±0.49)mm,(0.43±0.52)mm,(0.51±0.52)°.The corresponding PTV margine values were 5.19mm,4.06mm,3.76mm and 1.81mm,1.64mm,1.44mm respectively.The mean value of point absolute dose deviation andγpass rate were(0.14±1.54)%and(95.47±2.35)%.Compared with IMRT and VMAT,HT had advantages in the maximum dose o
作者
程晓龙
刘吉平
陈祥
王彬冰
潘林飞
张莉
CHENG Xiaolong;LIU Jiping;CHEN Xiang(Department of Radiation Physics,Zhejiang Cancer Hospital,Hangzhou 310022,China)
出处
《浙江医学》
CAS
2019年第20期2137-2141,2146,共6页
Zhejiang Medical Journal
基金
浙江省医药卫生科技计划项目(2018PY004)
关键词
胸中下段食管癌
螺旋断层放疗
剂量学比较
摆位误差
Middle-or lower-thoracic esophageal cancer
Helical tomotherapy
Dosimetric comparison
Setup errors
