Hytönen Roni, Vanderstraeten Reynald, Verbakel Wilko F A R
Varian, a Siemens Healthineers Company, Helsinki, Finland.
Varian, a Siemens Healthineers Company, Brussels, Belgium.
Phys Imaging Radiat Oncol. 2025 Jul 11;35:100809. doi: 10.1016/j.phro.2025.100809. eCollection 2025 Jul.
Delivery times of Bragg-peak-based intensity-modulated proton therapy fields play an important role in patient throughput and comfort. Despite the associated exit dose, single-layer proton transmission beams benefit from sharper penumbras and are extremely fast to deliver. In this study, we investigated the trade-offs in field delivery times (FDT) and plan quality when using both field types.
Reference treatment plans were created for eight left-sided breast and ten oropharynx cancer patients using an in-house automatic iterative optimizer. Comparative hybrid plans were created for each case. For breast, different combinations of transmission and conventional beams were evaluated. For oropharynx, two of the three conventional beams were replaced with six transmission beams. Hybrid plans were evaluated by comparing the dose metrics and FDT against the reference plans.
Hybrid breast plans exhibited mean and maximum organ at risk (OAR) doses, and target dose homogeneity and conformity comparable to the reference plans, while their FDTs decreased by median (interquartile range) of 58 %/166 s (56-61 %). Compared to reference plans, hybrid oropharynx plans exhibited higher mean OAR dose especially to oral cavity (median of 34 Gy vs 31 Gy) and spinal cord (20 Gy vs 11 Gy), while FDTs decreased by 73 %/91 s (71-73 %).
Depending on the case, hybrid planning can significantly reduce total FDT with only limited impact on plan quality. The reduced total FDT can improve patient comfort, reduce overall duration of the treatment, and improve beam scheduling at multi-room centers.
基于布拉格峰的调强质子治疗射野的递送时间对患者通量和舒适度起着重要作用。尽管存在相关的出射剂量，但单层质子透射束具有更锐利的半影，且递送速度极快。在本研究中，我们调查了同时使用这两种射野类型时在射野递送时间（FDT）和计划质量方面的权衡。
使用内部自动迭代优化器为8例左侧乳腺癌患者和10例口咽癌患者创建参考治疗计划。为每个病例创建对比性混合计划。对于乳腺癌，评估了透射束和传统束的不同组合。对于口咽癌，将三个传统束中的两个替换为六个透射束。通过将剂量指标和FDT与参考计划进行比较来评估混合计划。
混合乳腺癌计划的平均和最大危及器官（OAR）剂量、靶区剂量均匀性和适形性与参考计划相当，而其FDT中位数（四分位间距）降低了58%/166秒（56 - 61%）。与参考计划相比，混合口咽癌计划的平均OAR剂量更高，尤其是口腔（中位数34 Gy对31 Gy）和脊髓（20 Gy对11 Gy），而FDT降低了73%/91秒（71 - 73%）。
根据具体情况，混合计划可显著减少总FDT，而对计划质量的影响有限。总FDT的减少可提高患者舒适度、缩短治疗总时长，并改善多机房中心的射束调度。
