文章：

用于早期乳腺癌治疗的超高剂量率调强质子治疗中的铅笔束扫描布拉格峰FLASH技术

Pencil Beam Scanning Bragg Peak FLASH Technique for Ultra-High Dose Rate Intensity-Modulated Proton Therapy in Early-Stage Breast Cancer Treatment

原文发布日期：14 September 2023

DOI: 10.3390/cancers15184560

类型: Article

开放获取: 是

英文摘要：

Bragg peak FLASH-RT can deliver highly conformal treatment and potentially offer improved normal tissue protection for radiotherapy patients. This study focused on developing ultra-high dose rate (≥40 Gy × RBE/s) intensity-modulated proton therapy (IMPT) for hypofractionated treatment of early-stage breast cancer. A novel tracking technique was developed to enable pencil beaming scanning (PBS) of single-energy protons to adapt the Bragg peak (BP) to the target distally. Standard-of-care PBS treatment plans of consecutively treated early-stage breast cancer patients using multiple energy layers were reoptimized using this technique, and dose metrics were compared between single-energy layer BP FLASH and conventional IMPT plans. FLASH dose rate coverage by volume (V40Gy/s) was also evaluated for the FLASH sparing effect. Distal tracking can precisely stop BP at the target distal edge. All plans (n= 10) achieved conformal IMPT-like dose distributions under clinical machine parameters. No statistically significant differences were observed in any dose metrics for heart, ipsilateral lung, most ipsilateral breast, and CTV metrics (p> 0.05 for all). Conventional plans yielded slightly superior target and skin dose uniformities with 4.5% and 12.9% lower dose maxes, respectively. FLASH-RT plans reached 46.7% and 61.9% average-dose rate FLASH coverage for tissues receiving more than 1 and 5 Gy plan dose total under the 250 minimum MU condition. Bragg peak FLASH-RT techniques achieved comparable plan quality to conventional IMPT while reaching adequate dose rate ratios, demonstrating the feasibility of early-stage breast cancer clinical applications.

摘要翻译： 

布拉格峰FLASH放疗能够实现高度适形的治疗，并可能为放疗患者提供更好的正常组织保护。本研究聚焦于开发超高剂量率（≥40 Gy × RBE/s）的调强质子治疗技术，用于早期乳腺癌的大分割治疗。我们开发了一种新型追踪技术，使单能量质子的笔形束扫描能够适应靶区远端的布拉格峰。利用该技术，我们对连续收治的早期乳腺癌患者采用多能量层的标准笔形束扫描治疗方案进行了重新优化，并比较了单能量层布拉格峰FLASH计划与传统调强质子治疗计划的剂量学指标。同时评估了FLASH计划的体积剂量率覆盖情况，以分析FLASH保护效应。远端追踪技术能够精确地将布拉格峰止于靶区远端边缘。所有计划在临床机器参数下均实现了类似调强质子治疗的适形剂量分布。在心脏、同侧肺、大部分同侧乳腺及临床靶区的各项剂量学指标上均未观察到统计学显著差异。传统计划在靶区和皮肤剂量均匀性方面略优，最大剂量分别降低4.5%和12.9%。在最小250 MU条件下，FLASH放疗计划对计划总剂量超过1 Gy和5 Gy的组织分别实现了46.7%和61.9%的平均剂量率FLASH覆盖。布拉格峰FLASH放疗技术在达到足够剂量率比例的同时，获得了与传统调强质子治疗相当的计划质量，证明了其在早期乳腺癌临床应用的可行性。

原文链接：

Pencil Beam Scanning Bragg Peak FLASH Technique for Ultra-High Dose Rate Intensity-Modulated Proton Therapy in Early-Stage Breast Cancer Treatment