Speaker
Dr
Sebastien Incerti
(CNRS)
Description
Being able to understand and simulate adverse effects of ionizing radiation at the cellular and sub-cellular scale remains a challenge of today’s radiobiology research. The presented project, named “Geant4-DNA” [http://geant4-dna.org], was initiated by the European Space Agency. Its aim is to develop an experimentally validated simulation platform for modelling DNA damage induced by ionizing radiation.
This is an ambitious work of highly interdisciplinary nature, involving several fields (elementary particle physics, chemistry, molecular and cellular biology, and computing science). The platform is based on the general-purpose and open-source “Geant4” Monte Carlo simulation toolkit, and benefits from the toolkit’s full transparency and free availability.
This project develops specific functionalities in Geant4
i) The modelling of elementary physical interactions between ionizing particles and biological media (liquid water and DNA), during the so-called “physical” stage. The user can specify in a dedicated “physics list” class the particles and the corresponding physical processes these particles are sensitive to. Very recently, new models have been developed for the transport of proton and hydrogen in DNA material.
ii) The modelling of the “physico-chemical and chemical” stages corresponding to the production, the diffusion and the chemical reactions occurring between oxidative radical species. During the “physico-chemical” stage, the water molecules that have been excited and ionized during the physics stage may de-excite and dissociate into molecular radical species. In the “chemical stage”, these radicals may eventually react among themselves or with the DNA molecule. The implementation of reactive radical species in the Geant4 toolkit is currently in progress.
iii) The modelling of a “geometrical” stage where the two above stages are combined with a geometrical description of biological targets (such as chromatin segments, cell nuclei…). The Geant4-DNA physics processes and models are fully integrated into the Geant4 toolkit and can be combined with Geant4 geometry modelling capabilities. In particular, it becomes possible to implement the geometry of biological targets with a high resolution at the cellular scale and fully track particles within these geometries.
An overview of the developments undertaken by the Geant4-DNA collaboration including a description of software already available for download will be presented as well as future perspectives.
Primary author
Dr
Sebastien Incerti
(CNRS)