Monte Carlo-based modeling of secondary particle tracks generated by intermediate- and low-energy protons in water

This chapter gives an overview of recent developments in the Monte Carlo-based modeling of the interaction of ionizing radiation with biologically relevant systems. Several track structure codes, such as Geant4 (GEometry ANd Tracking 4), Geant4-DNA, and LEPTS (Low-Energy Particle Track Simulation), are described. Main features, areas of application and current limitations of each tool are discussed. A special attention is focused on the energy range covered by primary and secondary charged particles and on the type of interactions included in the simulation. A recent development of LEPTS is presented, aimed at the simulation of full slowing-down of protons in water together with all molecular processes involving secondary particles. The utilized approach allows one to study radiation effects on the nanoscale in terms of the number and the type of induced molecular processes