基于EPID在体剂量验证在肺癌和食管癌动态调强放疗中的应用研究  

Application of EPID-based in vivo dose verification in dynamic intensity-modulated radiotherapy for lung and esophageal cancers

作　　者：方家 朱万里[1] 戴春艳 杨昕[1] 孙红娟[1] 梅英杰 刘艳芳 丁叔波[1] Fang Jia;Zhu Wanli;Dai Chunyan;Yang Xin;Sun Hongjuan;Mei Yingjie;Liu Yanfang;Ding Shubo(Department of Radiation Oncology,Jinhua Municipal Central Hospital,Jinhua 321000,China;Shanghai United Imaging Healthcare Co.,Ltd.,Shanghai 201807,China)

机构地区：[1]浙江省金华市中心医院放疗科,金华321000 [2]上海联影医疗科技股份有限公司,上海201807

出　　处：《中华放射医学与防护杂志》2023年第9期705-711,共7页Chinese Journal of Radiological Medicine and Protection

基　　金：金华市公益性技术应用研究项目(2022-4-108)。

摘　　要：目的对肺癌和食管癌患者在放疗过程中行基于电子射野影像装置(EPID)的在体剂量验证,探讨影响在体剂量验证结果准确性的因素,并推荐应用在体剂量验证的流程及规范。方法单纯随机抽样法选取2022年5月至2022年8月在金华市中心医院放疗科行食管癌和肺癌放疗的患者32例(其中,肺癌14例,食管癌18例),在uRT-TPOIS计划系统上制作动态调强放疗(dIMRT)及EPID在体剂量验证(In vivo EPID)计划,使用uRT-linac 506c直线加速器进行治疗。治疗过程中行在体剂量验证,其中,肺癌病例行In vivo EPID的分次共238次,执行图像引导放疗(IGRT)共80次,食管癌病例行In vivo EPID的分次共414次,执行IGRT共105次。设置阈值并获取每个射野的2Dγ通过率,分析低于阈值的分次射野,并结合在线CT影像及三维重建剂量结果,进一步分析影响γ通过率下降的主要因素。结果肺癌、食管癌3 mm/5%γ通过率均值分别为95.1%±5.7%、96.5%±4.5%;3 mm/3%γ通过率均值为91.5%±8.4%、92.2%±4.9%;2 mm/2%γ通过率均值分别为:79.1%±14.1%、83.7.2%±8.2%,病种之间通过率差异无统计学意义(P>0.05)。靠近0°/180°射野组(A组)的γ通过率高于靠近90°/270°射野组(B组)(3 mm/5%,Z=-25.4,P<0.05;3 mm/3%,Z=-26.8,P<0.05)。通过IGRT纠正摆位误差,可显著提高γ通过率(IGRT和非IGRT下,3 mm/5%γ通过率均值为96.3%±5.1%、96.0%±4.9%,Z=-5.50,P<0.05;3 mm/3%γ通过率均值92.3%±8.0%、91.3%±7.7%,Z=-9.54,P<0.05)。肿瘤及正常组织体积变化和运动变化、定位和治疗前准备充分与否等都会影响在体剂量验证的结果。结论放疗过程中进行EPID在体剂量验证能避免错误照射,但需规范EPID在体剂量验证流程,以避免人为因素等导致的通过率降低。Objective To investigate the factors affecting the accuracy of electronic portal imaging device(EPID)-based in vivo dose verification in radiotherapy for patients with lung and esophageal cancers,and to recommend the workflow and specifications for the application of the in vivo dose verification.Methods This study randomly selected 32 patients who received radiotherapy for esophageal and lung cancers at the Department of Radiation Oncology,Jinhua Municipal Central Hospital from May to August 2022,including 14 lung cancer cases and 18 esophageal cancer cases.Using a uRT-linac 506c linear accelerator,these patients were treated according to the dynamic intensity-modulated radiotherapy(dIMRT)and EPID-based In vivo dose verification(In vivo EPID)plans developed with the uRT-TPOIS planning system.The In vivo dose verification performed during the treatment included 238 fractions of In vivo EPID and 80 fractions of image-guided radiotherapy(IGRT)for the lung cancer cases,as well as 414 fractions of In vivo EPID and 105 fractions of IGRT for the esophageal cancer cases.The 2Dγpassing rate for each irradiation field was obtained according to the set threshold value.Furthermore,fractioned irradiation fields withγ-passing rates below the threshold value were analyzed,and primary factors decreasing theγ-passing rate were further analyzed by combining the online CT images and 3D reconstruction-derived dose.Results For lung and esophageal cancers,the meanγ-passing rates were 95.1%±5.7%and 96.5%±4.5%,respectively at 3 mm/5%;91.5%±8.4%and 92.2%±4.9%,respectively at 3 mm/3%,and 79.1%±14.7%and 83.7%±8.2%,respectively at 2 mm/2%,indicating no statistically significant differences between two cancers(P>0.05).The averageγpassing rate for beam orientations near 0°/180°(Group A)was higher than those near 90°/270°(Group B)3 mm/5%:Z=-25.4,P<0.05;3 mm/3%:Z=-26.8,P<0.05).The IGRT correction of setup errors significantly improved theγpassing rates(96.3%±5.1%and 96.4%±4.9%,respectively at 3 mm/5%,Z=-5.50,P<0.05;92.3%±8.0

关 键 词：电子射野影像装置 在体剂量验证 放疗质量控制 自适应放疗 

分 类 号：R734.2[医药卫生—肿瘤] R735.1[医药卫生—临床医学]