Université catholique de Louvain, Institut de recherche expérimentale et clinique, Molecular Imaging and Radiation Oncology (MIRO) Laboratory, Brussels, Belgium.
Université catholique de Louvain, Institute of Information and Communication Technologies (ICTEAM), Louvain-La-Neuve, Belgium.
Acta Oncol. 2024 Oct 29;63:805-815. doi: 10.2340/1651-226X.2024.40549.
Intensity Modulated Proton Therapy (IMPT) faces challenges in lung cancer treatment, like maintaining plan robustness for moving tumors against setup, range errors, and interplay effects. Proton Arc Therapy (PAT) is an alternative to maintain target coverage, potentially improving organ at risk (OAR) sparing, reducing beam delivery time (BDT), and enhancing patient experience. We aim to perform a systematic plan comparison study between IMPT and energy layer (EL) and spot assignment algorithm - Proton Arc Therapy (ELSA-PAT) to assess its potential for lung cancer treatment.
A total of 14 Lung ELSA-PAT plans were compared retrospectively with IMPT plans. 4D worst-case minimax robust optimization was performed, including 84 scenarios (3%, 3 mm). Dosimetry assessment included target (clinical tumor volume [CTV]) and important OARs, on nominal and worst-case scenarios. Most relevant normal tissue complication probabilities (NTCP), target coverage robustness against interplay effect, and BDT were evaluated.
CTV D95% and D98% showed no significant difference in comparison. PAT demonstrated better conformality by 66% (p = 0.00012) but delivered a higher heart mean dose (HMD, 23%). There was a 2% increase in NTCP 2-year mortality risk with PAT. Total BDT was comparable among techniques. IMPT was more robust than PAT against interplay effect, considering both D1% (1.0 ± 0.8 Gy vs 1.1 ± 1.4 Gy) and D98% bandwidths (0.9 ± 0.9 Gy vs 1.1 ± 1.3 Gy).
Both techniques provide a similar level of dose coverage to the target volume. Although PAT improved dose conformality, higher HMD translated into increased heart toxicity, presumably due to chosen planning methodology and OAR proximity to target. Increased ELs and spots raised PAT BDT, although it could improve daily treatment workflow.
调强质子治疗（IMPT）在肺癌治疗中面临着挑战，如保持移动肿瘤的计划稳健性以对抗摆位、射程误差和相互作用效应。质子弧形治疗（PAT）是一种替代方法，可以维持靶区覆盖，有可能改善危及器官（OAR）的保护，减少束流传输时间（BDT），并提高患者体验。我们旨在对 IMPT 和能量层（EL）和点分配算法 - 质子弧形治疗（ELSA-PAT）进行系统的计划比较研究，以评估其在肺癌治疗中的潜力。
回顾性比较了 14 例肺部 ELSA-PAT 计划与 IMPT 计划。进行了 4D 最坏情况最小最大稳健优化，包括 84 种情况（3%，3mm）。在名义和最坏情况下对靶区（临床肿瘤体积[CTV]）和重要 OAR 进行了剂量评估。评估了最相关的正常组织并发症概率（NTCP）、靶区对相互作用效应的覆盖稳健性和 BDT。
CTV D95%和 D98%比较无显著差异。PAT 以 66%（p = 0.00012）的更好适形性，但心脏平均剂量（HMD）较高（23%）。PAT 导致 2 年死亡率风险的 NTCP 增加 2%。在技术方面，总 BDT 相当。考虑到 D1%（1.0 ± 0.8 Gy 与 1.1 ± 1.4 Gy）和 D98%带宽（0.9 ± 0.9 Gy 与 1.1 ± 1.3 Gy），IMPT 比 PAT 对相互作用效应更稳健。
两种技术都能为靶区提供相似的剂量覆盖水平。尽管 PAT 提高了剂量适形性，但较高的 HMD 导致心脏毒性增加，这可能是由于选择的计划方法和 OAR 靠近靶区。增加 EL 和点增加了 PAT BDT，尽管它可以改善日常治疗工作流程。
