开发一种使用荧光核径迹探测器 (FNTD) 评估临床质子和氦离子束的线性能量转移 (LET) 和相对生物有效性 (RBE) 的方法。FNTD 在固体水后面暴露于质子和氦气 - (4He -) 离子扩散布拉格峰 (SOBP)。探测器使用共焦显微镜成像，LET 光谱源自荧光强度。根据 LET 光谱计算轨迹平均 LET 和剂量平均 LET（分别为 LETF 和 LETD）。 LET 测量值用作 RBE 模型的输入来估计 RBE。人肺泡腺癌细胞 (A549) 暴露在与 FNTD 相同的位置。 RBE 是根据生成的生存曲线计算的。所有测量值均与蒙特卡罗模拟进行比较。对于质子，LETF 和 LETD 的测量值与模拟值之间的平均相对差异分别为 6% 和 19%。对于氦离子，两个数量的差异相同，均为 11%。对于质子和氦离子，实验 LET 光谱主峰的位置与模拟值分别在 9% 和 14% 以内。对于使用 LETD 作为输入的 RBE 模型，质子和氦离子的基于 FNTD 的 RBE 值范围分别为 1.02 ± 0.01 至 1.25 ± 0.04 和 1.08 ± 0.09 至 2.68 ± 1.26。这些值与模拟之间的平均相对差异为 2% 和 4%。对于 A549 细胞，质子和氦离子的 RBE 范围分别为 1.05 ± 0.07 至 1.47 ± 0.09，以及 0.89 ± 0.06 至 3.28 ± 0.20。关于 RBE 加权剂量（SOBP 处 2.0 Gy），模拟和测量之间的差异低于 0.10 Gy。这项研究首次证明 FNTD 可用于执行直接 LET 测量并估计临床质子中的 RBE和氦离子束。版权所有 © 2024。由 Elsevier Inc. 出版。

To develop a methodology for assessing the linear energy transfer (LET) and relative biological effectiveness (RBE) in clinical proton and helium-ion beams using fluorescent nuclear track detectors (FNTDs).FNTDs were exposed behind solid water to proton and helium- (4He-) ion spread-out Bragg peaks (SOBPs). Detectors were imaged with a confocal microscope, and the LET spectra were derived from the fluorescence intensity. The track- and dose-averaged LET (LETF and LETD, respectively) were calculated from the LET spectra. LET measurements were used as input on RBE-models to estimate the RBE. Human alveolar adenocarcinoma cells (A549) were exposed at the same positions as the FNTDs. The RBE was calculated from the resulting survival curves. All measurements were compared with Monte Carlo simulations.For protons, average relative differences between measurements and simulations were 6% and 19% for LETF and LETD, respectively. For helium ions the same differences were 11% for both quantities. The position of the experimental LET spectra primary peaks agreed with the simulations within 9% and 14% for protons and helium-ions, respectively. For the RBE-models using LETD as input, FNTD-based RBE values ranged from 1.02 ± 0.01 to 1.25 ± 0.04 and from 1.08 ± 0.09 to 2.68 ± 1.26 for protons and helium-ions, respectively. The average relative differences between these values and simulations were 2% and 4%. For A549 cells, the RBE ranged from 1.05 ± 0.07 to 1.47 ± 0.09 and from 0.89 ± 0.06 to 3.28 ± 0.20 for protons and helium-ions, respectively. Regarding the RBE-weighted dose (2.0 Gy at the SOBP), the differences between simulations and measurements were below 0.10 Gy.This study demonstrates for the first time that FNTDs can be used to perform direct LET measurements and to estimate the RBE in clinical proton and helium-ion beams.Copyright © 2024. Published by Elsevier Inc.