Amorphous track predictions in 'libamtrack' for alanine relative effectiveness in ion beams

摘要

Solid state dosimetry in therapeutic ion beams is seriously hampered by ionisation density effects. In most cases the use of empirical corrections is limited and therefore model predictions, especially from amorphous track models (ATMs), play a major role. Due to its high saturation dose and simple dose response, the alanine detector can help to study fundamental assumptions and accuracy in amorphous track modelling. The libamtrack project enabled recently to directly compare various flavours of ATMs. We therefore present here the potential of predictions for alanine from two libamtrack ATMs with experimental data as first part of a greater study. We find very good agreement for protons, helium and carbon ions for thin targets. For thick targets, however, the two compared algorithms show differences, with one generally better matching the data. Additional assumptions which have to be made on particle transport and stopping powers hinders a thorough interpretation of the deviation found and stress the necessity for a broader data base at lower particle energies.