利用锥形束CT研究不同部位食管癌放射治疗首周的摆位误差  

Set-up errors of different part on esophageal cancer in the first week of radiation treatment:using cone-beam computed tomography

作　　者：吴承骏[1] 管峦[1] 张伟[1] 秦颂兵[2] 

机构地区：[1]徐州市中心医院放疗科,江苏省221000 [2]苏州大学附属第一医院放疗科,江苏省215000

出　　处：《中华临床医师杂志（电子版）》2016年第2期194-197,共4页Chinese Journal of Clinicians(Electronic Edition)

摘　　要：目的利用机载千伏级锥形束CT(k V-CBCT)获取不同区段食管癌患者放射治疗第一周的摆位误差,分析不同部位食管癌摆位误差的区别。方法将43例食管癌患者按照原发病灶的位置分为A组(颈段及胸上段)和B组(胸中段及胸下段),对A组病例放射治疗时利用颈肩膜固定,对B组病例利用体膜固定。应用直线加速器机载k V-CBCT在放射治疗第一周进行每天1次扫描,采集的容积图像与计划CT图像匹配,获得左右(X轴)、前后(Y轴)、头足(Z轴)三个方向上的线性摆位误差。结果在X轴、Y轴、Z轴三个方向上的摆位误差分别为:A组(0.39±0.20)cm、(0.27±0.14)cm、(0.34±0.19)cm;B组(0.44±0.25)cm、(0.31±0.25)cm、(0.49±0.17)cm。三个方向上的计划靶区(PTV)外扩边界分别为:A组5.11 mm、4.36 mm、5.72 mm;B组6.79 mm、5.76 mm、7.38 mm。A组患者在X轴、Z轴方向上的摆位误差较B组减小,差异有统计学意义(P<0.05),而在Y轴方向上两者比较无统计学差异(P>0.05)。结论机载k V-CBCT可用于评估食管癌患者的摆位误差值,利用该摆位误差值可估算PTV的外扩边界。颈肩膜固定的准确性要优于体膜。Objective Using KV-CBCT to acquire the set-up errors of different part on esophageal cancer in the first week of radiation treatment,and analyze the difference of the set-up errors.Methods 43 patients receiving radical RT for carcinoma of the esophagus were divided into two groups,A group：the cervical and upper thoracic segment;B group：the middle and low thoracic segment.A group was fixed by neck-and-shoulder mold,B group was fixed by body mold.KV-CBCT were acquired on dayl to 5 daily.The images were imported into the planning system.The set-up errors on three axis（X left-right,Y front-back,Z head-foot） were acquired.Results The set-up errors on three axis of A group were X（0.39±0.20）cm,Y（0.27±0.14）cm,Z（0.34±0.19）cm.And the set-up errors of B group were X（0.44±0.25）cm,Y（0.31±0.25）cm,Z（0.49±0.17）cm.CTV referential safety margins of PTV in A group were X 5.11 mm,Y4.36 mm,Z 5.72 mm,and in B group were X 6.79 mm,Y 5.76 mm,Z 7.38 mm.The set-up errors in A group were lower than B group on the X,Z axis,and the difference was statistically significant（P〈0.05）.There was no statistical significance between two groups on the Y axis（P〈0.05）.Conclusions KV-CBCT can be used to evaluate the set-up errors of radiotherapy,which can be utilized to estimate the CTV referential safety margins of PTV.The fixation using neck-and-shoulder mold is more accurate than using body mold.

关 键 词：食管肿瘤 螺旋锥束计算机体层摄影术 放射治疗摆位误差 

分 类 号：R735.1[医药卫生—肿瘤] R730.55[医药卫生—临床医学]