Qi Hang, Hu Lei, Huang Sheng, Lee Yen-Po, Yu Francis, Chen Qing, Yang Yunjie, Kang Minglei, Zhai Huifang, Vermeulen Milo, Shim Andy, Park Peter, Ding Xuanfeng, Zhou Jun, Abramson David H, Francis Jasmine H, Simone Charles B, Barker Christopher A, Lin Haibo
New York Proton Center, New York, NY, USA.
Inova Schar Cancer Institute, Fairfax, VA, USA.
Radiat Oncol. 2025 Apr 2;20(1):48. doi: 10.1186/s13014-025-02621-y.
This study reports the single-institution clinical experience of multifield pencil beam scanning (PBS) intensity-modulated proton therapy (IMPT) and dosimetric comparison to proton arc for uveal melanoma (UM) in a regular PBS gantry room.
Eleven consecutive UM patients were treated with IMPT to 50 Gy in 5 fractions. A customized gaze-fixation device attached to the thermoplastic mask was used to reproduce the globe position for each patient. IMPT plans were robustly optimized with perturbations of 3 mm setup and 3.5% range uncertainties using 3-4 fields without apertures. Each plan was robustly reoptimized (using the same perturbation parameters) using two non-coplanar arc fields in the RayStation treatment planning system. Treatment quality for both plans was evaluated daily using CBCT-generated synthetic CT. Target coverage, conformity, and mean/maximum doses to adjacent organs were assessed.
Proton arc plans provided comparable plan quality compared to IMPT plans. Similar target coverage was achieved, with an average GTV D95% equal to 101.1% [Formula: see text] 1.0% and 101.4% [Formula: see text] 0.4% for IMPT and proton arc plans, respectively. Proton arc improves the conformity index (RTOG) compared to IMPT plans (average 0.96 [Formula: see text] 0.23 vs. 0.88 [Formula: see text] 0.18, p = 0.11). Both modalities met all the clinical goals for organs-at-risk (OARs), while proton arc significantly reduced the maximum dose for the retina from, on average, 54.5 [Formula: see text] 0.7 to 53.2 [Formula: see text] 0.3 Gy (p < 0.01). Treatment evaluation on synthetic CT showed that the doses received by patients were highly consistent with the planned doses, with a relative target coverage (D95%) difference within 3.5% for IMPT and 3.1% for proton arc, and the D95% of actual delivery exceeding 98.7% and 98.2%, respectively. The doses delivered to OARs did not exceed clinical constraints.
This is a novel report on proton arc for ocular tumors and gantry-based multifield PBS proton treatment for these tumors. This study demonstrated that both modalities can meet the clinical goals. The IMPT is currently clinically implanted, and 2-field non-coplanar proton arc plans can achieve comparable dosimetric metrics to those of IMPT plans when the deliver technique is matured.
本研究报告了在常规笔形束扫描（PBS）机架室中，多野笔形束扫描（PBS）调强质子治疗（IMPT）治疗葡萄膜黑色素瘤（UM）的单机构临床经验，并与质子弧形治疗进行剂量学比较。
连续11例UM患者接受IMPT治疗，分5次给予50 Gy。使用连接到热塑性面罩的定制注视固定装置来重现每位患者的眼球位置。IMPT计划在设置偏差3 mm和射程不确定度3.5%的情况下进行稳健优化，使用3 - 4个无孔径野。每个计划在RayStation治疗计划系统中使用两个非共面弧形野进行稳健重新优化（使用相同的扰动参数）。每天使用CBCT生成的合成CT评估两种计划的治疗质量。评估靶区覆盖、适形性以及相邻器官的平均/最大剂量。
质子弧形计划与IMPT计划相比提供了相当的计划质量。实现了相似的靶区覆盖，IMPT和质子弧形计划的平均GTV D95%分别等于101.1% [公式：见正文] 1.0%和101.4% [公式：见正文] 0.4%。与IMPT计划相比，质子弧形改善了适形指数（RTOG）（平均0.96 [公式：见正文] 0.23对0.88 [公式：见正文] 0.18，p = 0.11）。两种方式均满足所有危及器官（OARs）的临床目标，而质子弧形显著降低了视网膜的最大剂量，平均从54.5 [公式：见正文] 0.7降至53.2 [公式：见正文] 0.3 Gy（p < 0.01）。在合成CT上的治疗评估表明，患者接受的剂量与计划剂量高度一致，IMPT的相对靶区覆盖（D95%）差异在3.5%以内，质子弧形在3.1%以内，实际交付的D95%分别超过98.7%和98.2%。给予OARs的剂量未超过临床限制。
这是一篇关于质子弧形治疗眼部肿瘤以及基于机架的多野PBS质子治疗这些肿瘤的新报告。本研究表明两种方式均能满足临床目标。IMPT目前已临床应用，当交付技术成熟时，2野非共面质子弧形计划可实现与IMPT计划相当的剂量学指标。
