Proton therapy treatment plan verification in CCB Krakow using fred Monte Carlo TPS tool

Abstract

Monte Carlo (MC) methods account for many details of the interactions of particles with human tissue in proton beam therapy. The accuracy and fast dose calculation time offered by GPU-accelerated MC treatment planning systems (TPS) pushed development of such tools to support experimental treatment plan verification in the clinical routine. The GPU-accelerated MC-TPS Fred (Schiavi et al, Phys Med Biol 62:7482, 2017, [4]; University of Rome) is currently investigated in Cyclotron Centre Bronowice (CCB) Krakow proton beam therapy centre (Poland) that is in clinical operation from October 2016. The Krakow proton centre physical beam model has been implemented in Fred and was validated against Eclipse TPS calculations and patient Quality Assurance (QA) measurements in water phantom. We analyzed depth-dose distributions of single proton pencil beams and dose cubes of varying range and modulation in water. We used the gamma index method as quantitative measure and obtained a good agreement between Fred and analytical TPS calculations. We have also found that Fred reach proton tracking rates over 106 primaries per second. In the future, the proposed fast MC methods can help to reduce the time needed for experimental patient treatment plan verification measurements in water phantoms that are part of clinical routine procedures.