GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstraße 1, 64291 Darmstadt, Germany.
Med Phys. 2011 Oct;38(10):5448-58. doi: 10.1118/1.3633891.
Implementation and experimental assessment of a real-time dose compensation system for beam tracking in scanned carbon beam therapy of intrafractionally moving targets.
A real-time dose compensation functionality has been developed and implemented at the experimental branch of the beam tracking system at GSI Helmholtzzentrum für Schwerionenforschung (GSI). Treatment plans for different target geometries have been optimized. They have been delivered using scanned carbon ions with beam tracking (BT) and real-time dose compensation combined with beam tracking (RDBT), respectively. Target motion was introduced by a rotating table. Dose distributions were assessed by ionization chamber measurements and dose reconstructions. These distributions have been compared to stationary delivery for BT as well as RDBT. Additionally simulations have been performed to investigate the dependence of delivered dose distributions on varying motion starting phases for BT and RDBT, respectively.
Average measured dose differences between static delivery and motion influenced delivery could be reduced from 27-68 mGy when BT was used to 12-37 mGy when RDBT was used. Nominal dose was 1000 mGy. Simulated dose deliveries showed improvements in dose delivery and robustness against varying starting motion phases when RDBT was used.
A real-time dose compensation functionality extending the existing beam tracking functionality has been implemented and verified by measurements. Measurements and simulated dose deliveries show that real-time dose compensation can substantially improve delivered dose distributions for large rotational target motion compared to beam tracking alone.
在扫描碳离子束治疗内分次运动靶区的束流跟踪中，实现并实验评估实时剂量补偿系统用于束流跟踪的功能。
在 GSI 亥姆霍兹重离子研究中心（GSI）的束流跟踪系统的实验分支上，已经开发并实现了实时剂量补偿功能。针对不同的目标几何形状优化了治疗计划。它们分别使用带有束流跟踪（BT）和实时剂量补偿与束流跟踪（RDBT）的扫描碳离子束进行输送。目标运动通过旋转台引入。通过电离室测量和剂量重建来评估剂量分布。将这些分布与 BT 以及 RDBT 的静态输送进行了比较。此外，还进行了模拟，以研究 BT 和 RDBT 的运动起始相位变化对输送剂量分布的影响。
当使用 BT 时，从静态输送和受运动影响的输送之间的平均测量剂量差异可以从 27-68 mGy 降低到 12-37 mGy，而当使用 RDBT 时，名义剂量为 1000 mGy。模拟剂量输送显示，当使用 RDBT 时，在剂量输送和对变化的起始运动相位的稳健性方面有所改善。
已经实现并通过测量验证了扩展现有束流跟踪功能的实时剂量补偿功能。测量和模拟剂量输送表明，与单独使用束流跟踪相比，实时剂量补偿可以大大改善大旋转目标运动的输送剂量分布。
