瓦里安直线加速器机器性能检查中MV影像中心偏移量影响因素分析  

Factors affecting MV imager projection offset in machine performance check for Varian linear accelerator

作　　者：许刘杨 王晓银 王守宇 庞克华 孙丹丹 杨军[1] XU Liuyang;WANG Xiaoyin;WANG Shouyu;PANG Kehua;SUN Dandan;YANG Jun(Radiotherapy Technology Department,the First Affiliated Hospital of Xinxiang Medical University,Weihui 453100,China;He'nan Key Laboratory of Neurorestoratology,the First Affiliated Hospital of Xinxiang Medical University,Weihui 453100,China)

机构地区：[1]新乡医学院第一附属医院放射治疗技术科,河南卫辉453100 [2]新乡医学院第一附属医院河南省神经修复重点实验室,河南卫辉453100

出　　处：《中国医学物理学杂志》2024年第7期808-812,共5页Chinese Journal of Medical Physics

基　　金：河南省医学科技攻关计划联合共建项目(LHGJ20220622)。

摘　　要：目的:探究导致瓦里安Vitalbeam直线加速器机器性能检查(MPC)结果中MV影像中心偏移量异常的主要因素。方法:通过修复MV影像臂“肩部”电机编码器、锁定治疗床位置以及等中心校正方法观察MPC结果中MV影像中心偏移量数值并进行统计学分析。结果:修复MV影像臂编码器后,MPC结果中MV影像中心偏移量小于空白组且差异具有统计学意义[空白组:(0.450±0.010)mmvs维修编码器组:(0.310±0.001)mm]。等中心校正组MV影像中心偏移量与空白组相比差异无统计学意义。锁定治疗床组MV影像中心偏移量小于空白组且差异具有统计学意义[空白组:(0.450±0.010)mmvs锁定治疗床组:(0.240±0.030)mm]。维修影像臂编码器并做等中心校正之后进行MPC时锁定治疗床与不锁定治疗床的MV影像中心偏移量结果无统计学差异。结论:MV影像臂“肩部”电机编码器损伤是导致MV影像中心偏移量异常的主要因素,开始MV影像中心检查前锁定治疗床位置能降低当次检查结果,但是无法彻底解决MV影像中心偏移的问题。Objective To explore the main factors affecting the MV imager projection offset in the machine performance check(MPC)for Varian Vital Beam linear accelerator.Methods The MV imager projection offsets in the MPC after repairing the MV imaging arm encoder of shoulder motor,locking the treatment couch,and isocenter calibration were analyzed.Results MPC results revealed that the MV imager projection offset after repairing the MV imaging arm encoder of shoulder motor was(0.310±0.001)mm,significantly less than(0.450±0.010)mm in the blank group.The difference in MV imager projection offset between the isocenter calibration group and the blank group was trivial.The MV imager projection offset after locking the treatment couch was(0.240±0.030)mm,significantly less than(0.450±0.010)mm in the blank group.When MPC was carried out after repairing the imaging arm encoder and performing isocenter calibration,there was no significant statistical difference in MV imager center offset between the locked and unlocked treatment couch.Conclusion The damage of MV imaging arm encoder of shoulder motor is the main factor causing abnormal MV imager projection offsets.Locking the treatment couch before the MV imaging center check can reduce the results,but it cannot eliminate the MV imager projection offset.

关 键 词：直线加速器 机器性能检测 机载影像系统 编码器 等中心校正 

分 类 号：R815.6[医药卫生—放射医学]