数字模拟机对适形调强放射治疗患者进行射野核对的应用

目的 应用数字模拟定位机核对适形调强放射治疗计划,验证需要治疗的区域是否与靶区吻合.方法 收集头颈部、胸部、腹部肿瘤患者各30例,分别进行射野核对.将治疗计划系统（TPS）重建的0°和90°的数字重建图像（DRR）传至数字模拟机,移床从定位时的参考点移动到治疗时的等中心点,分别采集0°和90°的X射线影像;调用数字模拟机2D/2D matching程序,调整感兴趣区域（ROI）,设定10 cm×10 cm的射野区域为ROI,将0°DRR图与0°X射线影像、90°DRR图与90°X射线影像分别进行自动或手动分析匹配,查看ROI内的两组图像的骨性结构是否吻合,最后得出两组图像匹配后的误差.结果 分析头颈部、胸部、腹部各30例肿瘤患者进行射野核对后的误差以及校正后的误差,头颈部肿瘤在X、Y、Z方向误差均≤3 mm,胸腹部肿瘤在X、Y、Z方向误差均≤5 mm.结论 数字模拟机能够通过DRR图与X射线影像分析匹配的方式对适形调强放射治疗的计划进行核对,验证治疗区域,从而保证治疗的准确性,满足了临床需要.

Application of digital simulator in radiation field verification of intensity modulated radiation therapy

Objective To test whether the treatment volume is consistent with the target volume under digital simulator.Methods The patients were divided into head and neck,thoracic,and abdominal cancer groups,with 30 cases in each group,and the radiation fields were verified.The 0° and 90° digital reconstructed radiograph (DRR) images reconstructed by treatment planning system (TPS) was transported to digital simulator.The simulator bed was moved from reference point for positioning to isocenter point for radiotherapy.Then the 0°and 90°X ray images were collected.2D/2D matching program was applied to accommodate the region of interest (ROI).A 10 cm× 10 cm area in the radiotherapy field was set as the ROI,and the 0° and 90° DRR images matched with the corresponding X ray image automatically or manually.The bony structures of ROI in the two corresponding images were verified for consistence,and the correction error between the two images was calculated.Results The error after radiation field verification and correction error were analyzed in each group.The error was less than 3 mm on X,Y and Z axis in head and neck cancer group and less than 5 mm in thoracic and abdominal cancer group,respectively.Conclusions The digital simulator can verify the treatment volume and guarantee the accuracy during radiotherapy,which satisfy the clinical requirements.