CBCT和EXT图像引导系统在高级别脑胶质瘤放疗中的应用分析

Application of combined cone-beam CT and ExacTrac X-ray image-guided system in high-grade glioma radiotherapy

目的:运用锥形束CT(cone-beam CT,CBCT)联合ExacTrac X射线(ExacTrac X-Ray,ETX)图像引导系统对高级别脑胶质瘤放疗患者进行首次与剩余分次放疗的位置验证,探讨最优的图像引导验证模式。方法:回顾性分析2018年1月至2020年6月在某院接受脑胶质瘤调强放疗的20例患者的资料,首次治疗患者使用CBCT图像引导系统确定治疗中心在体表的对应位置,并进行复位与标记,之后在线将CBCT图像与定位CT图像进行自动配准,运用ETX图像引导系统来验证残余摆位误差;剩余分次治疗使用ETX图像引导系统对摆位误差进行位置验证。计算患者在六维方向[Lat方向(左右)、Lng方向(头脚)、Vrt方向(前后)、Pitch方向(绕左右旋转)、Roll方向(绕头脚旋转)、Yaw方向(绕前后旋转)]上的摆位误差及其区间分布。采用SPSS 22.0统计学软件进行数据分析。结果:首次治疗患者的摆位误差只需1次校正的占比为75.00%,剩余分次治疗患者的摆位误差只需1次校正的占比为78.62%。首次治疗经CBCT联合ETX图像引导复位均能满足治疗要求;剩余分次治疗中,在六维方向上校正前后的摆位误差值比较,差异有统计学意义(P<0.05)。摆位误差区间分布显示,患者在首次治疗和剩余分次治疗中六维方向上的误差值均在0~1 mm和0°~1°。结论:高级别脑胶质瘤患者术后采用CBCT联合ETX图像引导系统进行首次及剩余分次治疗,能快速、准确地确认治疗中心并复位,减小摆位误差,可提高治疗的准确性与重复性。

Objective To explore the optimal image-guided verification mode by using combined cone-beam CT(CBCT)and ExacTrac X-ray(ETX)image-guided system for the position verification during the first and remaining fractionated radiotherapy of high-grade glioma patients.Methods Twenty high-grade glioma patients undergoing intensity-modulated radiotherapy at some hospital from January 2018 to June 2020 were analyzed retrospectively.CBCT image-guided system was used for the patients treated for the first time to determine the corresponding position of the treatment center on the body surface and to reset and mark the treatment center,then on-line auto registration of the CBCT images with CT positioning images was carried out,and the residual setup errors were verified with ETX image-guided system;position verification of the setup errors was performed with ETX image-guided sysem during the remaining fractionated treatment.The setup errors and their interval distributions were calculated for the patients in six directions including left-right direction(Lat),head-foot direction(Lng),anterior-posterior direction(Vrt),rotation around left-right(Pitch),rotation around head-foot(Roll)and rotation around anterior-posterior(Yaw).SPSS 22.0 statistical software was used for data analysis.Results There were 75%patients treated for the first time and 78.62%ones undergoing the remaining fractionated radiotherapy only needed one time of setup error corre-ction.Combined CBCT and ETX image-guided resetting during the first radiotherapy met clinical requirements;during the remaining fractionated radiotherapy there were significant differences between the setup errors in the six directions before and after calibration(P<0.05).The interval distribution of setup errors showed the error values in the six directions were all restricted within 0 to 1 mm and within 0°to 1°during the first and remaining fractionated radiotherapy.Conclusion Involve-ment of combined CBCT and ETX image-guided system in the first and remaining fractionated radiotherapy of high-grade glioma patients after operation contributes to determining and resetting the treatment center rapidly and accurately,decreasing setup errors and enhancing the accuracy and repeatability of radiotherapy.