六维床在颅内肿瘤立体定向放射治疗中的临床应用

Clinical application of PerfectPitch 6D couch in the stereotactic radiotherapy of intracranial tumors

目的:探讨六维床在颅内肿瘤立体定向放射治疗(SRT)中的临床应用价值。方法:对行SRT的37例颅内肿瘤患者采用个体化头热塑网罩联合发泡胶制作的个体化头枕与碳纤维底板固定,CT模拟定位获取治疗计划参考图像,每次治疗前行锥形束CT(CBCT)扫描,CBCT图像采用骨窗模式与计划参考图像配准,采用Varian Edge直线加速器机载CBCT影像引导,用六维治疗床在线校正摆位误差。误差校正后再次行CBCT扫描,将CBCT图像与计划参考图像进行再次配准,记录配准结果,比较六维床校正前后的误差结果。结果:颅内肿瘤首次摆位误差中,三个平移方向X、Y、Z的摆位误差分别为(0.114±0.071)cm、(0.096±0.077)cm、(0.090±0.069)cm.,3个旋转方向Rx,Ry,Rz的摆位误差分别为(0.737±0.451)°、(0.748±0.384)°、(0.701±0.381)°。六维床在线校正后获得残余误差结果,3个平移方向X、Y、Z的残余误差分别为(0.020±0.016)cm、(0.012±0.012)cm、(0.014±0.011)cm,3个旋转方向Rx,Ry,Rz的残余误差分别为(0.080±0.080)°、(0.076±0.075)°、(0.076±0.075)°,6个方向上校正前后差异均有统计学意义(P值均为0.000)。结论:影像引导下的六维治疗床对颅内肿瘤SRT的摆位误差有明显的纠正作用,建议在颅内肿瘤立体定向放射治疗时,采用六维方向在线校正摆位误差。

Objective：To investigate the clinical application of PerfectPitch 6D couch in the stereotactic radiotherapy（SRT）of intracranial tumors.Methods：SRT was performed in 37 patients with intra-cranial tumor by using individualized polyurethane foam sealing agent pillow in combination with individualized thermoplastic veil and carbon fibre soleplate.CT images were obtained for the reference of radiotherapy planning.Cone beam CT（CBCT）was performed before each session of therapy.Bone window images were matched with the images of CT for radiotherapy planning.Using CBCT affiliated to the Varian Edge linear accelerator for guidance,the position errors were revised by PerfectPitch 6D couch on line.The images of CBCT were regained and re-matched with the images of CT.The results were noted and statistically analyzed.Results：Of the initial setup errors in intra-cranial tumor,the positioning errors of X,Y,Z direction was（0.114±0.071）cm、（0.096±0.077）cm、（0.090±0.069）cm,respectively,the positioning error of 3 rotation directions Rx,Ry and Rz was（0.737±0.451）°、（0.748±0.384）°、（0.701±0.381）°respectively.After revising by the PerfectPitch 6D couch,the remained linear errors and rotation errors that matched between the images of CBCT and the images of CT on X-,Y-and Z-axial was（0.020±0.016）cm、（0.012±0.012）cm、（0.014±0.011）cm respectively,and the rotation error was（0.080±0.080）°、（0.076±0.075）°、（0.076±0.075）°respectively.There were significant statistic differences before and after revision in all these 6 directions（all P=0.000）.Conclusion：The imaging guided six dimensional treatment bed has a significant correction effect on the setup error of intracranial tumor SRT.It is recommended that the positioning error should be corrected online in six dimensional directions when using stereotactic radiotherapy for the treatment of intra-cranial tumor.