Center for Proton Therapy, Paul Scherrer Institute, ETH Domain, CH-5232 Villigen, Switzerland.
Center for Proton Therapy, Paul Scherrer Institute, ETH Domain, CH-5232 Villigen, Switzerland.
Phys Med. 2024 Nov;127:104817. doi: 10.1016/j.ejmp.2024.104817. Epub 2024 Oct 11.
We present the dosimetric evaluation of craniospinal irradiation (CSI) treatments delivered with protons at Paul Scherrer Institute (PSI), with special focus on local recurrences and late toxicity outcome.
This study included 71 children, adolescents and young adults (c-AYA), who received or intended to receive (3 patients, pts) CSI using PBS-PT at PSI between 2004 and January 2021. The most frequent primary tumours were: medulloblastoma (42 pts), ependymoma (8 pts) and germ cell tumors (6 pts). The patients were treated prone on Gantry1 (G1; 22 pts) up to 2017, and afterwards supine on Gantry2 (G2; 49 pts). Accuracy of prone vs. supine setup was evaluated. Nine patients received CSI for local failure (LF) after a first course of local fractionated radiation therapy (RT). For 59/71 patients (excluding three patients not receiving PBS-PT CSI and nine preirradiated) CSI plans were compared considering gantry and planning technique. Detailed analysis of the full treatment (CSI and boost series) was performed for 8 patients presenting with LFs (4 of them presented also distal failure) and for selected patients presenting with late toxicity (G2 to G4) or asymptomatic radiation-induced radiological findings.
Supine positioning resulted in lower systematic and random errors as compared to prone (0.25 mm and 0.4 mm systematic errors respectively for supine and prone; random errors in PA direction reduced from 1.8 mm for prone to 1.4 mm for supine).
LFs were not correlated with potential dose inaccuracies or lack of robustness and no correlation of toxicities to enhanced LET have been observed.
我们介绍了保罗谢勒研究所（PSI）使用质子进行颅脊髓照射（CSI）治疗的剂量评估，特别关注局部复发和晚期毒性结果。
本研究纳入了 71 名儿童、青少年和年轻成人（c-AYA），他们在 2004 年至 2021 年 1 月期间在 PSI 接受或计划接受 PBS-PT 进行 CSI。最常见的原发性肿瘤是：髓母细胞瘤（42 例）、室管膜瘤（8 例）和生殖细胞瘤（6 例）。患者在 2017 年之前采用 Gantry1（G1；22 例）俯卧位治疗，之后采用 Gantry2（G2；49 例）仰卧位治疗。评估了俯卧位与仰卧位设置的准确性。9 名患者在首次局部分次放射治疗（RT）后因局部失败（LF）接受 CSI。对于 59/71 名患者（不包括未接受 PBS-PT CSI 的 3 名患者和 9 名预照射患者），考虑到龙门架和计划技术，对 CSI 计划进行了比较。对于 8 名出现 LF（其中 4 名出现远端失败）和出现晚期毒性（G2 至 G4）或无症状放射性影像学发现的选定患者，对整个治疗（CSI 和增强系列）进行了详细分析。
仰卧位的系统误差和随机误差均低于俯卧位（仰卧位系统误差分别为 0.25mm 和 0.4mm；仰卧位在 PA 方向的随机误差从俯卧位的 1.8mm 降低至 1.4mm）。
LF 与潜在剂量不准确或缺乏稳健性无关，也未观察到毒性与增强 LET 之间的相关性。
