基于CBCT研究中上段食管癌放疗摆位误差及CTV外放边界确定  

Analysis of the upper and middle segment esophageal setup errors and planning target margin based on CBCT for esophageal radiation with thermoplastic film immobilized

作　　者：时勇 朱建国[2] 张琳[2] 李东 张芬 闫勤英 刘艳丽[3] 李苓 张敏[3] 李成建 高泽宇[2] SHI Yong;ZHU Jian-guo;ZHANG Lin;LI Dong;ZHANG Fen;YAN Qin-ying;LIU Yan-li;LI Ling;ZHANG Min;LI Cheng-jian;GAO Ze-yu(School of Medicine and Life Sciences,University of Jinan-Shandong Academy of Medical Sciences, Jinan 250200,P.R.China;Institute of Radiation Medicine Shandong Academy of Medical sciences,Jinan 250000,P.R.China;Department of Radiation,Affiliated Tengzhou Central Hospital of Jining Medical University, Tengzhou 277500,P.R.China)

机构地区：[1]济南大学.山东省医学科学院医学与生命科学学院,山东济南250200 [2]山东省医学科学院放射研究所,山东济南250000 [3]济宁医学院附属滕州市中心人民医院放疗室,山东滕州277500

出　　处：《中华肿瘤防治杂志》2019年第8期545-548,共4页Chinese Journal of Cancer Prevention and Treatment

基　　金：国家重点研发计划(2017YFC0107502);济宁医学院教师科研扶持基金(JYFC2018FKJ151)

摘　　要：目的摆位误差是确定食管癌肿瘤计划靶区外放边界最重要的影响因素,本研究采用锥形束CT(cone beam CT,CBCT)研究胸腹热塑体膜固定下的中、上段食管癌放疗摆位误差,推算中、上段食管癌临床靶区(clinicaltarget volum,CTV)的外放边界。方法选取2015-08-10-2017-01-12济宁医学院附属滕州市中心人民医院行胸腹体膜固定体位的60例中、上段食管癌放疗患者,利用CBCT于第1、10、20次治疗前采集CBCT图像,比对并记录治疗靶区的摆位误差,计算其CTV外放值并分析各方向位移量及旋转度的变化。结果 60例患者摆位误差在左右(x)、上下(y)、前后(z)方向分别为(2.93±2.24)、(3.81±2.31)和(2.41±1.65)mm,俯仰(θ)、滚转(Φ)、偏转(ψ)角度分别为(2.08±1.32)°、(1.53±1.03)°和(1.65±1.14)°。由公式计算出CTV在x、y、z方向分别需外放7.39、7.83和5.91mm;摆位误差在y、z方向位移量分别与Φ、ψ角旋转度相关,Pearson分别为-0.532和-0.51,均P<0.05;分次间变化仅在z方向上位移量与ψ角旋转度相关,Pearson=-0.576,P<0.05。结论胸腹热塑体膜固定下的中、上段食管癌CTV的外放边界在左右、上下、前后方向应≥7.39、7.83、5.91mm。应重视呼吸运动对摆位误差带来的影响,进一步改良体位固定方法和优化摆位操作流程。OBJECTIVE To evaluate the setup errors in patients with upper and middle segment esophageal cancer who underwent cone beam computed tomography(CBCT)immobilized by thermoplastic film and to probe the margins using the esophageal clinical target volume(CTV)in three directions.METHODS A total of 60 patients with upper and middle segment esophageal cancer were enrolled.All patients were immobilized by thermoplastic film and underwent CBCT at the first,tenth,and twentieth treatment after positioning,respectively.These CBCT images were registered to the planning CT to determine setup errors in translational and rotational directions.Then,CTV margins were calculated from the systematic and random errors.RESULTS Setup errors on(left-right),(superior-inferior),and(anteroposterior)translational directions were(2.93±2.24),(3.81±2.31)and(2.41±1.65)mm and onθ(pitch degree),(roll degree)andψ(yaw degree)rotational directions were(2.08±1.32)°,(1.53±1.03)°and(1.65±1.14)°,respectively.The margins from CTV were 7.35,8.09 and 5.94 mm in x,y,and zdirections,respectively.In the and directions,translational errors were significantly correlated withandψdegree rotational errors(Pearson=-0.511,-0.503,P<0.05).In the inter-fraction,only on direction,setup changes were considered significantly correlated withψdegree(Pearson=-0.571,P<0.05).CONCLUSIONS In patients with upper and middle segment esophageal cancer immobilized by thermoplastic film,the margins from CTV were recommended to be not less than 7.39,7,83,and 5.91 mm in x,y,and zdirections,respectively.The position immobilization method and positioning workflow should be improved further to reduce the influence of breathing movement on setup errors.

关 键 词：食管癌 摆位误差 锥形束CT 放射治疗 

分 类 号：R735.1[医药卫生—肿瘤]