Baiocco G, Alloni D, Babini G, Mariotti L, Ottolenghi A
Department of Physics, University of Pavia, Pavia, Italy INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy
Department of Physics, University of Pavia, Pavia, Italy INFN, National Institute of Nuclear Physics, Sezione di Pavia, Pavia, Italy LENA, Laboratory of Applied Nuclear Energy, University of Pavia, Pavia, Italy.
Radiat Prot Dosimetry. 2015 Sep;166(1-4):316-9. doi: 10.1093/rpd/ncv134. Epub 2015 Apr 5.
Neutron relative biological effectiveness (RBE) is found to be energy dependent, being maximal for energies ∼1 MeV. This is reflected in the choice of radiation weighting factors wR for radiation protection purposes. In order to trace back the physical origin of this behaviour, a detailed study of energy deposition processes with their full dependences is necessary. In this work, the Monte Carlo transport code PHITS was used to characterise main secondary products responsible for energy deposition in a 'human-sized' soft tissue spherical phantom, irradiated by monoenergetic neutrons with energies around the maximal RBE/wR. Thereafter, results on the microdosimetric characterisation of secondary protons were used as an input to track structure calculations performed with PARTRAC, thus evaluating the corresponding DNA damage induction. Within the proposed simplified approach, evidence is suggested for a relevant role of secondary protons in inducing the maximal biological effectiveness for 1 MeV neutrons.
中子相对生物效应（RBE）被发现与能量有关，在能量约为1兆电子伏时最大。这反映在用于辐射防护目的的辐射权重因子wR的选择上。为了追溯这种行为的物理起源，有必要对能量沉积过程及其全部依赖性进行详细研究。在这项工作中，蒙特卡罗输运代码PHITS被用于表征在一个“人体大小”的软组织球形模型中负责能量沉积的主要次级产物，该模型由能量约为最大RBE/wR的单能中子辐照。此后，次级质子的微剂量学表征结果被用作输入，以进行PARTRAC的径迹结构计算，从而评估相应的DNA损伤诱导情况。在所提出的简化方法中，有证据表明次级质子在诱导1兆电子伏中子的最大生物效应方面发挥了相关作用。
