Pinnacle计划系统脚本在医用直线加速器碰撞防护中的应用

Application of scripts in Pinnacle TPS for collision protection in linac-based radiotherapy

目的:探讨在放疗计划设计阶段使用Pinnacle计划系统脚本程序,实现医用直线加速器旋转治疗时的碰撞检测功能,提高放疗计划设计的可执行性,保证治疗安全。方法:根据C型臂加速器的治疗机头、病人CT图像和治疗床的几何结构信息,确定机架旋转过程中距离治疗中心的最小安全距离。在Pinnacle计划系统中设计脚本程序,根据当前放疗计划射野治疗中心的位置,模拟生成加速器机头旋转过程中临界安全位置的运动轨迹,并以辅助感兴趣区(ROI)的形式导入计划系统,在计划系统的CT和ROI的叠加影像上判断加速器机头与治疗床、病人是否存在碰撞风险。结果:脚本程序可根据当前病人摆位、治疗中心位置等计划设置参数,自动生成辅助ROI结构并导回计划系统,在CT图像的横断面上辅助ROI轨迹为圆形结构。计划设计时,只需一次鼠标点击,即可快速(约2 s)生成辅助ROI。在CT与ROI的叠加图像上可以逐层清楚直观地判断当前计划参数是否存在碰撞风险,避免计划实际执行时才发现会碰撞。结论:在Pinnacle计划系统上实现加速器机头的碰撞检测具有临床可行性,使用本方法在计划设计阶段可及时判断放疗计划是否存在碰撞风险,避免重复计划延误治疗时间,保证治疗安全。

Objective To realize the collision detection during linac-based radiotherapy by applying the scripts of Pinnacle treatment planning system(TPS)in treatment planning,thereby improving the reliability of radiotherapy planning and ensuring the safety of treatment.Methods According to the geometry information of the gantry of C-arm accelerator,patient's CT images and treatment couch,the minimum safety distance between the treatment center and rotating gantry was determined.Pinnacle TPS was used to design scripts.The motion trajectory of the critical safe position during gantry rotation was simulated according to the field center of the radiotherapy plan.Then the motion trajectory was imported into Pinnacle TPS in the form of region of interest.Finally,based on the superimposed image of CT images and ROI,it would be determined whether there was a risk of collision between accelerator gantry and treatment couch or the patient.Results According to the setting parameters such as patient positioning and treatment center,the scripts could generate the auxiliary ROI structure automatically and import it back into the planning system.The auxiliary ROI track was showed as a circular structure on the cross section of the CT image.During radiotherapy planning,the auxiliary ROI was generated quickly(within 2 s)after a single mouse click.On the superimposed image of ROI and CT images,it could be clearly and intuitively determined whether there was a risk of collision in the current treatment plan,thus avoiding collisions when the plan was delivered.Conclusion Implementing the collision detection in Pinnacle TPS is proved to be clinically feasible.During the stage of treatment planning,it is possible to determine whether there is a risk of collision in current radiotherapy plan by the proposed method,thereby avoiding the time delay caused by the repeat of treatment planning and ensuring the safety of treatment.