Search

Understanding the fundamental mechanisms involved in the induction of biological damage by ionizing radiation remains a major challenge of todays radiobiology research. The Monte Carlo simulation of physical, physicochemical and chemical processes involved may provide a powerful tool for the simulation of early damage induction. The Geant4-DNA extension of the general purpose Monte Carlo Geant4 simulation toolkit aims to provide the scientific community with an open source access platform for the mechanistic simulation of such early damage. This paper presents the most recent review of the Geant4-DNA extension, as available to Geant4 users since June 2015 (release 10.2 Beta). In particular, the review includes the description of new physical models for the description of electron elastic and inelastic interactions in liquid water, as well as new examples dedicated to the simulation of physicochemical and chemical stages of water radiolysis. Several implementations of geometrical models of biological targets are presented as well, and the list of Geant4-DNA examples is described.

Agradecimentos: The Geant4-DNA project received funding from the French Agence Nationale de la Recherche contract number ANR-09-BLAN-0135-01 and from the European Space Agency BioRad Project under contract number AO6041-22712/09/NL/AT. It was also supported in part by the RFBR 09-02-91065 grant and the CNRS PICS-4865 grant. The Region Aquitaine, France, funded the computing farm used in this work through the RESEARCH project. M. Bernal thanks the FAEPEX fund, UNICAMP, and the FAPESP foundation (FAPESP 2011/51594-2), both in Brazil, for financing his research activities. This work has been developed as a part of the activities planned in the Programme de Cooperation ECOS-Sud A09E04 Abstract: In the perspective of building an open source simulation platform dedicated to the modelling of early biological molecular damages due to ionising radiation at the DNA scale, the general-purpose Geant4 Monte Carlo simulation toolkit has been recently extended with specific very low energy electromagnetic physics processes for liquid water medium. These processes - also called "Geant4-DNA" processes - simulate the physical interactions induced by electrons, hydrogen and helium atoms of different charge states. The present work reports on the energy deposit distributions obtained for incident electrons, protons and alpha particles in nanometre-size volumes comparable to those present in the genetic material of mammalian cells. The frequency distributions of the energy deposition obtained for three typical geometries of nanometre-size cylindrical targets placed in a spherical phantom are found to be in reasonable agreement with prior works. Furthermore, we present a combination of the Geant4-DNA processes with a simplified geometrical model of a cellular nucleus allowing the evaluation of energy deposits in volumes of biological interest FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP Fechado