体部肿瘤精确放疗摆位误差分析

目的:确定体部肿瘤精确放疗时的摆位误差。方法:使用电子射野影像系统EPID对28例体部肿瘤病人精确放疗时所拍摄的378幅射野图像与计划系统生成的数字重建放射片DRR进行比较,并对病人摆位的左右(x)和前后(y)及头脚(z)方向误差进行测量。结果:各方向摆位误差的分布均近似正态分布。胸部的摆位偏差主要发生在y、z方向,腹部和盆腔部的摆位偏差主要发生在x、z方向。结论:体位的随机误差大于系统误差,摆位所带来的偏差主要来源于随机误差。

Analysis of the Body Tumors Set-up Errors in Precise Radiotherapy

Objective: To determine the magnitude of the set-up errors in precise radiotherapy for body tumors. Methods: 378 films form 28 patients were recorded using the electronic portal imaging device EPID, and compared with digitally reconstructed rediograph DRR. The deviation of set-up for 28 patients in the left-right (x), anterior-posterior (y) and superior-inferior (z) directions were measured and analyzed. Results: The distribution of set-up errors in every direction approximated a normal distribution. The set-up deviations in the chest occurred mainly in y and z directions. The set-up deviations in the abdomen and pelvis occurred mainly in x and z directions. Conclusions: The random error was larger than systematic error. The set-up deviations are mainly came from the random errors.