Conte V, Selva A, Colautti P, Hilgers G, Rabus H, Bantsar A, Pietrzak M, Pszona S
INFN-Legnaro National Laboratories, Viale dell'Università 2, Legnaro, Italy.
Department of Physics and Astronomy, University of Padova, via Marzolo 8, Padova, Italy.
Radiat Prot Dosimetry. 2018 Aug 1;180(1-4):150-156. doi: 10.1093/rpd/ncx175.
The biological action of ionizing charged particles is initiated at the DNA level, and the effectiveness with which the initial physical effect changes into measurable biological damage is likely ruled by the stochastics of ionizations produced by the incident ions in subcellular nanometric volumes. Based on this hypothesis, experimental nanodosimetry aims at establishing a new concept of radiation quality that builds on measurable characteristics of the particle track structure at the nanometer scale. Three different nanodosimetric detection systems have been developed to date that allow measurements of the number of ionizations produced by the passage of a primary particle in a nanometer-size gas volume (in unit density scale). Within the Italian project MITRA (MIcrodosimetry and TRAck structure), funded by the Italian Istituto Nazionale di Fisica Nucleare (INFN) and the EMRP Joint Research Project 'BioQuaRT' (Biologically Weighted Quantities in Radiotherapy), experiments have been carried out, in which the frequency distribution of ionizations produced by proton and carbon ion beams of given energy was measured with the three nanodosimetric detectors. Descriptors of the track structure can be derived from these distributions. In particular, the first moment M1, representing the mean number of ionizations produced in the target volume, and the cumulative probability Fk of measuring a number ν ≥ k of ionizations. The correlation between measured nanodosimetric quantities and experimental radiobiological data available in the literature is here presented and discussed.
带电粒子的生物作用始于DNA水平，而初始物理效应转变为可测量生物损伤的有效性可能由入射离子在亚细胞纳米体积中产生的电离随机性所决定。基于这一假设，实验纳米剂量学旨在建立一种新的辐射质量概念，该概念基于纳米尺度上粒子径迹结构的可测量特征。迄今为止，已开发出三种不同的纳米剂量检测系统，这些系统能够测量初级粒子通过纳米尺寸气体体积时产生的电离数量（以单位密度尺度表示）。在由意大利国家核物理研究所（INFN）资助的意大利项目MITRA（微剂量学与径迹结构）以及EMRP联合研究项目“BioQuaRT”（放射治疗中的生物加权量）中，已经开展了相关实验，其中使用这三种纳米剂量探测器测量了给定能量的质子和碳离子束产生的电离频率分布。径迹结构的描述符可以从这些分布中得出。特别是，一阶矩M1表示在目标体积中产生的平均电离数，以及测量到电离数ν≥k的累积概率Fk。本文展示并讨论了测量的纳米剂量学量与文献中可用的实验放射生物学数据之间的相关性。
