通过线性能量转移过的物理剂量的研究,用于评估碳离子治疗中的治疗计划
Mansure Schafasand1,2, Andreas Franz Resch1, Ankita Nachankar1,3
1MedAustron Ion Therapy Center, Wiener Neustadt, Austria.
Medical physics
|September 20, 2023
概括
一种新的指标,即高LET剂量,可以区分小型和大型瘤的碳离子治疗计划. 这种方法可以通过分析基于线性能量转移 (LET) 的剂量分布来改善放射治疗中临床结果的预测.
科学领域:
- 医学物理 医学物理
- 辐射瘤学 辐射瘤学
- 放射治疗剂量计 放射治疗剂量计
背景情况:
- 大型瘤与碳离子放射治疗 (CIRT) 的较差结果有关.
- 瘤大小会影响低线性能量转移 (LET) 剂量的比例,这可能会影响治疗的有效性.
- 目前的方法,如剂量平均的LET,可能无法完全捕捉CIRT中混合辐射场的复杂性.
研究的目的:
- 评估一种新的剂量计量量,即高LET剂量 (HLD),作为一个单一参数,以区分小型和大型瘤的碳离子治疗计划 (cTP).
- 建立一个最佳的LET值来计算HLD,有效地区分瘤体积.
- 评估HLD在改善CIRT治疗计划方面的潜力.
主要方法:
- 选择了19个cTP (10个大,9个小瘤) 并分析了临床目标体积 (CTV) 内的基于voxel的高LET剂量分布.
- 研究了18个LET值,以确定一个最佳的值 (LET值) 以基于HLD分布描述符 (平均值,方差,斜率) 来区分瘤大小.
- 使用剂量-体积直方图概念来比较HLD和小和大瘤组之间的剂量分布,采用t测试或曼-惠特尼-U测试来确定统计学意义.
主要成果:
- 确定大约70keV/μm的LET值是对分类瘤大小有效的.
- 小型CTV在确定值时,与大型CTV相比,其 HLD 的平均值和中位数显著更高.
- 平均接近最小的HLD为小瘤的0.31±0.08 Gy,而大瘤的0.20±0.01 Gy,差异为2.7 Gy.
结论:
- 该研究表明,使用高剂量的LET用于评估碳离子处理计划的可行性.
- 在较大的瘤的治疗计划中观察到较低的高LET剂量,这表明其在区分瘤大小方面的实用性.
- 需要进一步的研究才能将这些发现转化为临床实践,但该方法为未来基于HLD的研究提供了一个有希望的方法.
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