Dosimetric impact of systematic spot position errors in spot scanning proton therapy of head and neck tumor
Dosimetric impact of systematic spot position errors in spot scanning proton therapy of head and neck tumor
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DOI：
10.4103/jcrt.jcrt_389_21
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发表时间：
2023-04
影响因子：
1.3
通讯作者：
K. Yasui;Yuta Omi;Akira Shimomura;Rie Muramatsu;H. Iwata;H. Ogino;N. Hayashi
中科院分区：
文献类型：
--
作者：
K. Yasui;Yuta Omi;Akira Shimomura;Rie Muramatsu;H. Iwata;H. Ogino;N. Hayashi
目的：光斑位置是扫描质子治疗质量保证中的重要射束参数。在本研究中，我们使用头颈部肿瘤的三种优化方法研究了点扫描质子治疗中系统 15 点位置误差 (SSPE) 的剂量影响。材料和方法：在 X 和 Y 方向上使用 ± 2 mm 模型 SSPE 进行规划模拟。使用调强质子治疗（IMPT）和单场均匀剂量（SFUD）制定治疗计划。 IMPT 计划是通过两种优化方法创建的：使用最坏情况优化 (WCO-IMPT) 和不使用 (IMPT)。对于临床目标体积（CTV），使用D95%、D50%和D2cc进行分析。对于危及器官（OAR），Dmean用于分析大脑、耳蜗和腮腺，Dmax用于分析脑组、视交叉、视神经和脊髓。结果：对于 CTV，D95% 相对于 WCO-IMPT、IMPT 和 SFUD 计划的变异（1 个标准差）分别为 ± 0.88%、0.97% 和 0.97%。 CTV 的 D50% 和 D2cc 的变化在所有计划中均显示 <0.5% 的变化。 OAR 中由 SSPE 引起的剂量变化较大，最坏情况优化减少了剂量变化，尤其是 Dmax 中。分析结果表明SSPE对SFUD影响不大。结论：我们阐明了 SSPE 对三种优化方法剂量分布的影响。 SFUD 被证明是针对 OAR 的稳健治疗计划，并且 WCO 可用于提高 IMPT 中 SSPE 的稳健性。
Purpose: The spot position is an important beam parameter in the quality assurance of scanning proton therapy. In this study, we investigated dosimetric impact of systematic 15 spot position errors (SSPE) in spot scanning proton therapy using three types of optimization methods of head and neck tumor. Materials and Methods: The planning simulation was performed with ± 2 mm model SSPE in the X and Y directions. Treatment plans were created using intensity-modulated proton therapy (IMPT) and single-field uniform dose (SFUD). IMPT plans were created by two optimization methods: with worst-case optimization (WCO-IMPT) and without (IMPT). For clinical target volume (CTV), D95%, D50%, and D2cc were used for analysis. For organs at risk (OAR), Dmean was used to analyze the brain, cochlea, and parotid, and Dmax was used to analyze brainsetem, chiasm, optic nerve, and cord. Results: For CTV, the variation (1 standard deviation) of D95% was ± 0.88%, 0.97% and 0.97% to WCO-IMPT, IMPT, and SFUD plan. The variation of D50% and D2cc of CTV showed <0.5% variation in all plans. The dose variation due to SSPE was larger in OAR, and worst-case optimization reduced the dose variation, especially in Dmax. The analysis results showed that SSPE has little impact on SFUD. Conclusions: We clarified the impact of SSPE on dose distribution for three optimization methods. SFUD was shown to be a robust treatment plan for OARs, and the WCO can be used to increase robustness to SSPE in IMPT.