Demonstration of the FLASH Effect Within the Spread-out Bragg Peak After Abdominal Irradiation of Mice.
Demonstration of the FLASH Effect Within the Spread-out Bragg Peak After Abdominal Irradiation of Mice.
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DOI：
10.14338/ijpt-20-00095
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发表时间：
2022
影响因子：
1.7
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中科院分区：
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研究了在扩散布拉格峰 (SOBP) 处传递的 FLASH 水平剂量率对小鼠正常组织损伤的影响。 50 只非肿瘤小鼠接受腹部照射，其中 30 只接受 FLASH 剂量率（100 Gy/s）照射，20 只接受常规剂量率（0.1 Gy/s）照射。总剂量值范围为 10 至 19 Gy，由同步回旋加速器质子治疗系统在单个点上传递。以腹部为中心，所传递的准直视野是一个直径为 11 毫米的圆圈，从入口到远端 80% 剂量的水当量深度为 2.4 厘米。使用脊形过滤器来提供整个 2.4 厘米范围内的剂量均匀性。 FLASH 和传统递送的空间分布是相同的。暴露日期后 21 天追踪小鼠的总生存率和个体小鼠体重，并比较 FLASH 组和常规剂量率组的 LD50 值。与暴露于常规剂量率的小鼠相比，暴露于FLASH剂量率的小鼠具有更高的LD50值，存活率呈剂量依赖性提高10%至20%。 FLASH 队列还显示研究中每天的群体存活率更高或相同。这些结果初步证实了布拉格峰的优点与 FLASH 治疗的正常组织保护益处相结合的潜力。该实验还证实脉冲同步回旋加速器可用于 FLASH 研究和治疗的目的。
The effects of FLASH-level dose rates delivered at the spread-out Bragg peak (SOBP) on normal tissue damage in mice were investigated. Fifty nontumor-bearing mice received abdominal irradiation, 30 at FLASH dose rates (100 Gy/s) and 20 at conventional dose rates (0.1 Gy/s). Total dose values ranged from 10 to 19 Gy, delivered in a single spot by a synchrocyclotron proton therapy system. Centered on the abdomen, the collimated field delivered was an 11-mm diameter circle with a water-equivalent depth of 2.4 cm from entrance to distal 80% dose. A ridge filter was used to provide dose uniformity over the full 2.4-cm range. The spatial distribution was identical for both the FLASH and conventional deliveries. Overall survival and individual mouse weights were tracked for 21 days after the exposure date, and LD50 values were compared for the FLASH and conventional dose rate groups. Mice exposed to FLASH dose rates had a higher LD50 value as compared with mice exposed to conventional dose rates, with a dose-dependent improvement in survivability of 10% to 20%. The FLASH cohort also showed greater or equal percent population survival for each day of the study. These results are preliminary confirmation of the potential for the combination of the advantages of the Bragg peak with the normal tissue sparing benefits of FLASH treatments. This experiment also confirms that pulsed synchrocyclotrons can be used for the purpose of FLASH research and treatment.