INFN Laboratori Nazionali di Legnaro, viale dell'Università 2, I-35020 Legnaro, Italy.
UHasselt, Faculty of Engineering Technology, Centre for Environmental Sciences, Nuclear Technology Center, Agoralaan 3590 Diepenbeek, Belgium.
Phys Med Biol. 2023 Jan 17;68(3). doi: 10.1088/1361-6560/acabfe.
. Microdosimetry offers a fast tool for radiation quality (RQ) verification to be implemented in treatment planning systems in proton therapy based on variable LET or RBE to move forward from the use of a fixed RBE of 1.1. It is known that the RBE of protons can increase up to 50% higher than that value in the last few millimetres of their range. Microdosimetry can be performed both experimentally and by means of Monte Carlo (MC) simulations. This paper has the aim of comparing the two approaches.. Experimental measurements have been performed using a miniaturized Tissue equivalent proportional counter developed at the Legnaro National Laboratories of the Italian National Institute for Nuclear Physics with the aim of being used as RQ monitors for high intensity beams. MC simulations have been performed using the microdosimetric extension of TOPAS which provides optimized parameters and scorers for this application.. Simulations were compared with experimental microdosimetric spectra in terms of shape of the spectra and their average values. Moreover, the latter have been investigated as possible estimators of LET obtained with the same MC code. The shape of the spectra is in general consistent with the experimental distributions and the average values of the distributions in both cases can predict the RQ increase with depth.. This study aims at the comparison of microdosimetric spectra obtained from both experimental measurements and the microdosimetric extension of TOPAS in the same radiation field.
微剂量学提供了一种快速的辐射品质（RQ）验证工具，可以在质子治疗计划系统中实现，该系统基于可变 LET 或 RBE，以从使用固定 RBE（1.1）向前发展。众所周知，质子的 RBE 可以在其射程的最后几毫米内增加高达 50%。微剂量学可以通过实验和蒙特卡罗（MC）模拟来进行。本文旨在比较这两种方法。实验测量是使用在意大利国家核物理研究所的 Legnaro 国家实验室开发的微型组织等效比例计数器进行的，目的是将其用作高强度束的 RQ 监测器。MC 模拟是使用 TOPAS 的微剂量扩展进行的，该扩展为该应用提供了优化的参数和评分器。模拟结果在光谱形状和平均值方面与实验微剂量光谱进行了比较。此外，还研究了这些平均值作为使用相同 MC 代码获得的 LET 的可能估计值。光谱的形状通常与实验分布一致，在这两种情况下，分布的平均值都可以预测 RQ 随深度的增加而增加。本研究旨在比较在相同辐射场中从实验测量和 TOPAS 的微剂量扩展获得的微剂量学光谱。
