食管癌患者首次摆位行锥形束CT验证的误差分析

目的:探讨食管癌患者首次摆位行锥形束CT验证的重要性.方法:对接受图像引导放射治疗(IGRT)的92例食管癌患者,首次摆位采用锥形束CT影像技术(CBCT),获得图像与计划CT图像进行匹配校正,获得X、Y、Z轴及矢状轴旋转摆位误差共368个数据.结果:X轴误差为(0.22±0.19)cm,其中胸下段组为(0.34±0.26) cm.Y轴误差为(0.40±0.28)cm,其中颈段和胸上段组为(0.45±0.34)cm.Z轴误差为(0.34±0.26)cm,其中胸中段组为(0.38±0.27) cm.矢状轴旋转误差为(0.11±0.12)°.结论:CBCT可减少食管癌首次摆位误差.建议根据肿瘤生长位置外放计划靶体积(PTV).

Analysis the first setup errors in esophageal cancer by CBCT

OBJECTIVE:To investigate the importance of first setup checked by CBCT in patients with esophageal cancer.METHODS:There were 92 patients with esophageal cancer accepting IGRT.During the course of first setup,the images obtained by cone-beam computed tomography(CBCT) and that obtained by CT digital reconstruction were matched and corrected.Three hundred and sixty-eight records of error were abtained from X-axis,Y-axis,Z-axis and sagittal axis.RESULTS:The error of X-axis was(0.22±0.19) cm in which the error of the lower thoracic group was(0.34±0.26) cm.The error of Y-axis was(0.40±0.28) cm in which the error of the cervical and upper thoracic group was(0.45±0.34) cm.The error of Z-axis was(0.34±0.26) cm in which the error of the middle thoracic group was(0.38±0.27) cm.The error of sagittal axis was(0.11±0.12)°.CONCLUSIONS:CBCT can reduce the first setup errors of the patients with esophageal cancer.These give some advices to doctors to treat patients in planned target volume(PTV) based on the locations of tumor.