食管癌个体化临床靶区-计划靶区外扩边界剂量研究及摆位误差分析  

Individualized CTV-to-PTV margin dose and analysis of positioning errors in esophageal cancer

作　　者：齐英男 麦秀滢 姜晓勃[1] 刘红冬 朱文龙 赵磊[1] 迟锋[1] QI Yingnan;MAI Xiuying;JIANG Xiaobo;LIU Hongdong;ZHU Wenlong;ZHAO Lei;CHI Feng(State Key Laboratory of Oncology in South China,Guangdong Provincial Clinical Research Center for Cancer,Department of Radiotherapy,Sun Yat-sen University Cancer Center,Guangzhou 510060,China)

机构地区：[1]华南恶性肿瘤防治全国重点实验室,广东省恶性肿瘤临床医学研究中心,中山大学肿瘤防治中心放疗科,广东广州510060

出　　处：《中国医学物理学杂志》2023年第12期1453-1458,共6页Chinese Journal of Medical Physics

基　　金：国家自然科学基金(81874220);广东省食管癌研究所科技计划(M202222)。

摘　　要：目的:研究食管癌放疗个体化临床靶区(CTV)-计划靶区(PTV)外扩边界剂量及摆位误差,在合理的剂量要求下提高放疗治疗精度。方法:选取2021年6月到2022年6月中山大学肿瘤防治中心黄埔院区收治的54例食管癌患者为研究对象,所有患者分次内均行锥形束CT(CBCT)图像扫描,共收集1283次CBCT图像。在患者放疗前进行CBCT扫描,将CBCT图像与计划CT图像匹配,得到腹背方向(VRT)、头脚方向(LNG)、左右方向(LAT)、旋转横断位(Roll)、旋转矢状位(Pitch)、旋转冠状位(YAW)6个方向的误差。同时分别对54例患者前5次6个维度方向摆位误差计算出均值,利用单样本t检验方法,与全分次摆位误差进行比较,判断差异性。并利用公式(外放边界=2.5∑+0.7δ)计算出PTV外放边界。将计算得出的外扩边界分为5组:A组(所有方向均外扩5 mm),B组(LAT方向外扩7.9 mm,其它方向5 mm),C组(LNG方向外扩11.03 mm,其它方向5 mm),D组(VRT方向外扩6.36 mm,其它方向5 mm),E组(LAT方向外扩7.9 mm,LNG方向外扩11.03 mm,VRT方向外扩6.36 mm)对10例患者进行模拟计划制作。结果:通过统计学分析得出54例患者六维方向前5次误差均值与全分次误差差异性占比,54例患者6个维度方向共324个方向,其中192个方向(59.26%)差异没有统计学意义(P>0.05)。其中LAT方向占比总病例数64.81%;LNG方向占比总病例数57.41%;VRT方向占比总病例数51.85%;Pitch方向占比总病例数64.81%;Roll方向占比总病例数57.41%;YAW方向占比总病例数59.26%。计算出CTV-PTV外扩边界为LAT=7.90 mm,LNG=11.03 mm,VRT=6.36 mm。运用统计学分析对比5组外扩边界下各危及器官及靶区覆盖率,结果均无统计学意义(P>0.05)。结论:采用食管癌放疗前5次摆位误差预测后续摆位误差具有一定可行性,食管癌放疗合理的个体化外扩边界在不增大危及器官受照量的同时可以减少治疗分次间脱靶率,为食管癌靶区外扩提供参考,为精准治疗提Objective To analyze the individualized CTV-to-PTV margin dose and positioning errors in radiotherapy for esophageal cancer for improving the treatment accuracy while meeting dose requirements.Methods Fifty-four esophageal cancer patients admitted to Sun Yat-sen University Cancer Center at Huangpu District from June 2021 to June 2022 were enrolled.All of the patients underwent CBCT scans in each fraction,and a total of 1283 CBCT images were collected.The image registration between CBCT image before radiotherapy and planning CT image was carried out to obtain errors in vertical(VRT),longitudinal(LNG),lateral(LAT),Roll,Pitch,and YAW directions.The mean values of six-dimensional positioning errors in the first 5 fractions were calculated,and the results were compared with the total fractional errors using the single sample t-test method for determining the differences.The CTV-to-PTV margin was calculated with the formula(margin=2.5∑+0.7δ),and the calculated margins were divided into 5 groups:Group A(5 mm expansion in all directions),Group B(7.9 mm expansion in LAT direction,and 5 mm expansion in other directions),Group C(11.03 mm expansion in LNG direction,and 5 mm expansion in the other directions),Group D(6.36 mm expansion in VRT direction,and 5 mm expansion in the other directions),and Group E(7.9 mm expansion in LAT direction,11.03 mm expansion in LNG direction,and 6.36 mm expansion in VRT direction).Simulation planning was conducted for 10 patients.Results The proportions of differences between the mean values of six-dimensional errors in the first 5 fractions and the total fractional errors in 54 patients were analyzed.There was no significant difference in 192 out of the 324 directions in 54 patients,accounting for 59.26%(P>0.05).Among them,the LAT,LNG,VRT,Pitch,Roll and YAW directions accounted for 64.81%,57.41%,51.85%,64.81%,57.41%and 59.26%of the total cases.The calculated CTV-to-PTV margin was 7.90,11.03 and 6.36 mm in LAT,LNG and VRT directions.The statistical analysis showed that the differences in t

关 键 词：食管癌 六维方向 剂量学 靶区个体化外扩 误差分析 

分 类 号：R318[医药卫生—生物医学工程]