Bert Christoph, Saito Nami, Schmidt Alexander, Chaudhri Naved, Schardt Dieter, Rietzel Eike
Med Phys. 2007 Dec;34(12):4768-71. doi: 10.1118/1.2815934.
Treatment of moving targets with scanned particle beams results in local over- and under-dosage due to interplay of beam and target motion. To mitigate the impact of respiratory motion, a motion tracking system has been developed and integrated in the therapy control system at Gesellschaft für Schwerionenforschung. The system adapts pencil beam positions as well as the beam energy according to target motion to irradiate the planned position. Motion compensation performance of the tracking system was assessed by measurements with radiographic films and a 3D array of 24 ionization chambers. Measurements were performed for stationary detectors and moving detectors using the tracking system. Film measurements showed comparable homogeneity inside the target area. Relative differences of 3D dose distributions within the target volume were 1 +/- 2% with a maximum of 4%. Dose gradients and dose to surrounding areas were in good agreement. The motion tracking system successfully preserved dose distributions delivered to moving targets and maintained target conformity.
由于束流与靶区运动的相互作用，用扫描粒子束治疗运动靶区会导致局部剂量过高和过低。为减轻呼吸运动的影响，德国重离子研究中心已开发出一种运动跟踪系统并将其集成到治疗控制系统中。该系统根据靶区运动调整笔形束位置以及束流能量，以照射计划位置。通过使用射线照相胶片和24个电离室的3D阵列进行测量，评估了跟踪系统的运动补偿性能。使用跟踪系统对固定探测器和移动探测器进行了测量。胶片测量显示靶区内具有相当的均匀性。靶区内三维剂量分布的相对差异为1±2%，最大为4%。剂量梯度和对周围区域的剂量吻合良好。运动跟踪系统成功地保留了传递到运动靶区的剂量分布并保持了靶区适形性。
