Elastic scattering cross section models used for Monte Carlo simulation of electron tracks in media of biological and medical interest

Abstract

Purpose: Elastic scattering is important for the spatial distribution of electrons penetrating matter, and thus for the distribution of deposited energy and DNA damage. Scattering media of interest are in particular liquid and gaseous water and gaseous nitrogen. The former are used as surrogates for tissue and cell environments (since more than 70% of the cell consists of water), while cross section data for nitrogen have been scaled and used as input in Monte Carlo (MC) codes simulating scattering in biologically relevant media. A short review is given of electron elastic scattering cross section models used in a biological and medical context and their experimental and theoretical background.

Conclusions: Adequate theories and models exist for calculating elastic electron scattering in gaseous nitrogen and gaseous water (i.e., by free molecules) down to electron energies well below 100 eV. However, elastic electron scattering in liquid water at such low energies is apparently uncertain and not well understood. Further studies in the case of liquid water are thus motivated due to its biological importance.

Keywords::

• Electron scattering
• electron tracks
• elastic scattering cross section