Dose point kernels in liquid water: An intra-comparison between GEANT4-DNA and a variety of Monte Carlo codes

Modeling the radio-induced effects in biological medium still requires accurate physics models to describe the interactions induced by all the charged particles present in the irradiated medium in detail. These interactions include inelastic as well as elastic processes. To check the accuracy of the very low energy models recently implemented into the GEANT4 toolkit for modeling the electron slowing-down in liquid water, the simulation of electron dose point kernels remains the preferential test. In this context, we here report normalized radial dose profiles, for mono-energetic point sources, computed in liquid water by using the very low energy “GEANT4-DNA” physics processes available in the GEANT4 toolkit. In the present study, we report an extensive intra-comparison of profiles obtained by a large selection of existing and well-documented Monte-Carlo codes, namely, EGSnrc, PENELOPE, CPA100, FLUKA and MCNPX.

► Normalized radial dose profiles are reported for mono-energetic electron sources. ► The low-energy “GEANT4-DNA” physics package is used for the calculations. ► A comparison with a large number of electron track-structure codes is proposed. ► Evident discrepancies in terms of shape and magnitude are reported. ► Accurate dose profiles have been provided by the GEANT4-DNA code.