Analogue Monte Carlo to model radiation-induced DNA damage

Radiation induced DNA damage is dependent on the inchoative distributions of direct ionisations and excitations, and of the indirect action of all species and radicals created or set in motion at early times within a few angstroms distance. These distributions are used to initiate the physico-chemical, chemical and biological stages, with reactions, attacks, repair, non-repair,.. So, a simple target model like a small piece of DNA cannot be considered as an homogeneous medium but as a composite one with (i) DNA structure with nucleotides, bases, sugar and phosphate, (ii) hydration shell tightly bound, and (iii) surrounding bulk water where active species and radicals are created. (orig.)