Numerical insight into the Dual Radiation Action Theory.

Autor: Tello JJ; Instituto de Física 'Gleb Wataghin', Universidade Estadual de Campinas, Brazil; University of Pavia, Physics Department, via Bassi 6, I-27100 Pavia, Italy; INFN-Sezione di Pavia, via Bassi 6, I-27100 Pavia, Italy., Incerti S; CNRS, IN2P3, CENBG, UMR 5797, F-33170 Gradignan, France; University of Bordeaux, CENBG, UMR 5797, F-33170 Gradignan, France., Francis Z; Saint Joseph University, Faculty of Science, R.U. Mathematics and Modelling, Department of Physics, Beirut, Lebanon., Tran H; IRFU/DPhN, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France., Bernal MA; Instituto de Física 'Gleb Wataghin', Universidade Estadual de Campinas, Brazil. Electronic address: mabernal@ifi.unicamp.br.
Jazyk: angličtina
Zdroj: Physica medica : PM : an international journal devoted to the applications of physics to medicine and biology : official journal of the Italian Association of Biomedical Physics (AIFB) [Phys Med] 2017 Nov; Vol. 43, pp. 120-126. Date of Electronic Publication: 2017 Nov 06.
DOI: 10.1016/j.ejmp.2017.10.022
Abstrakt: This work studies the first and second order mechanisms for the induction of lethal lesions in DNA after irradiation with protons and α-particles. The purpose is to numerically study the mechanisms behind the Dual Radiation Action Theory (DRAT) for these heavy particles. A genetic material geometrical model with atomic resolution is used. It accounts for the explicit position of 5.47 × 10 9 base pairs, organized up to the chromatin level. The GEANT4-DNA Monte Carlo code was employed to simulate the interaction of these ions with the genetic material model. The number of lethal lesions induced by one- and two-track mechanisms was determined as a function of dose. Values of the α/β ratio were estimated as well as corresponding relative biological effectiveness (RBE). The number of lethal lesions produced by one-track and two-track mechanisms depends on the dose and squared dose, respectively, as predicted by the DRAT. RBE values consistent with experimental results were found, at least for LET below ∼100 keV/μm. Double strand break spatial distributions are qualitatively analyzed. According to this work, the α parameter determined from cellular surviving curves depends on both the physical α and β parameters introduced here, and on the specific energy deposited by a single track into the region of interest. We found an increment of the β parameter with LET, yet at a slower rate than α so that the α/β ratio increases with LET. In addition, we observed and explained the saturation of the α parameter as the dose increases above ∼6 Gy.
(Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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