Eur. Phys. J. D (2015) 69: 216
https://doi.org/10.1140/epjd/e2015-60206-5

Regular Article

Energy dependent track structure parametrisations for protons and carbon ions based on nanometric simulations^*

¹ Department of Radiation Oncology, Technische Universität München, Klinikum rechts der Isar, Ismaninger Straße 22, 81675 München, Germany
² Institut de Radioprotection et Sûreté Nucléaire (IRSN), 92262 Fontenay-aux-Roses, France
³ Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig, Germany

^a e-mail: Frauke.Alexander@tum.de

Received: 31 March 2015
Received in final form: 13 July 2015
Published online: 17 September 2015

Abstract

The BioQuaRT project within the European Metrology Research Programme aims at correlating ion track structure characteristics with the biological effects of radiation and develops measurement and simulation techniques for determining ion track structure on different length scales from about 2 nm to about 10 μm. Within this framework, we investigate methods to translate track-structure quantities derived on a nanometre scale to macroscopic dimensions. Input data sets were generated by simulations of ion tracks of protons and carbon ions in liquid water using the Geant 4 Monte Carlo toolkit with the Geant4-DNA processes. Based on the energy transfer points − recorded with nanometre resolution − we investigated parametrisations of overall properties of ion track structure. Three different track structure parametrisations have been developed using the distances to the 10 next neighbouring ionisations, the radial energy distribution and ionisation cluster size distributions. These parametrisations of nanometric track structure build a basis for deriving biologically relevant mean values which are essential in the clinical situation where each voxel is exposed to a mixed radiation field.