自制“倾倒式”治疗床减小胸腹部肿瘤放疗摆位误差可行性与有效性

目的 CT模拟定位和放疗过程中均使用自制“倾倒式”治疗床进行摆位,探讨其减小摆位误差的可行性和有效性。方法 选取 2016年3-9月于肿瘤医院进行放疗的 22例胸腹部肿瘤患者,根据是否使用“倾倒式”治疗床随机分为2个组,每组 11例。试验组使用“倾倒式”治疗床实现患者由直立位转换至仰卧位,对照组采用常规的患者自主仰卧位。所有患者均在自主呼吸的状态下接受定位CT扫描,根据IGRT协作组的规范化建议进行图像配准。记录并分析CBCT扫描平移误差和旋转误差配准数据,根据“四参数模型”计算2个组摆位误差。结果 试验组x、y、z轴向平移误差和范围分别为(-0.012±0.128)、(0.272±0.123)、(0.089±0.105) cm和 0.29~0.70、0.23~0.70、0.14~0.53 cm,对照组的分别为(0.006±0.198)、(-0.108±0.396)、(-0.096±0.176) cm和 0.27~0.75、0.56~2.08、0.34~0.89 cm。结论 自制“倾倒式”治疗床可以提高胸腹部肿瘤放疗的摆位重复性,减少摆位误差,尤其是y轴向上的摆位误差。

Feasibility and effectiveness of self-made tiltable treatment couch in minimizing setup errors of radiotherapy for thoracic and abdominal tumors

Objective A self-made tiltable treatment couch was adopted for CT simulation positioning and radiotherapy to evaluate the feasibility and effectiveness to minimize the setup errors. Methods Twenty-two patients with thoracic and abdominal tumors receiving radiotherapy in Department of Radiation Oncology,Peking Union Medical College between March and September 2016 were recruited in this study. All patients were randomly divided into the experimental (n=11) and control groups (n=11).In the study group,the tiltable treatment couch was adopted to switch the patients from the standing position to the supine position,and conventional supine position was utilized in the control group. All patients received CT positioning under spontaneous breathing. Image registration was performed according to the standard recommendations of IGRT group. The image registration data for the translational and rotation errors of CBCT were recorded and analyzed. The setup errors were calculated by four-parameter model between two groups. Results In the experimental group,the translational error of the x direction was (-0.012±0.128) cm with a variation range of (0.29-0.70 cm),(0.272±0.123) cm for the y direction (0.23-0.70 cm) and (0.089±0.105) cm for the z direction (0.14-0.53 cm),respectively. In the control group,the translational error of the x direction was (0.006±0.198) cm (0.27-0.75 cm),(-0.108±0.396) cm for the y direction (0.56-2.08 cm) and (-0.096±0.176) cm for the z direction (0.34-0.89 cm),respectively. Conclusions Application of the self-made tiltable treatment couch can enhance the setup reproducibility and reduce the setup errors,especially in the y direction during radiotherapy for the thoracic and abdominal tumors.