Abstract ID: 45 Development and analysis of the track-LET, dose-LET and RBE calculations with a therapeutical proton and ion beams using Geant4 Monte Carlo code. (October 2017)

• Record Type: Journal Article
• Authors: Petringa, Giada; Pablo Cirrone, Giuseppe Antonio; Cuttone, Giacomo; Pandola, Luciano; Milluzzo, Giuliana Giuseppina; Pisciotta, Pietro; Russo, Giorgio; Romano, Francesco
• Is Part Of: Physica medica. Volume 42(2017)Supplement 1
• Page Start: 9
• Publication Date: 2017-10
• Subjects: Medical physics -- Periodicals; Biophysics -- Periodicals; Biophysics -- Periodicals; Imagerie médicale -- Périodiques; Radiothérapie -- Périodiques; Rayons X -- Sécurité -- Mesures -- Périodiques; Physique -- Périodiques; Médecine -- Périodiques; 610.153
• DOI: 10.1016/j.ejmp.2017.09.023
• Languages: English
• ISSNs: 1120-1797

Abstract

Abstract : A reliable prediction of the spatial Linear Energy Transfer(LET) distribution in a biological tissues is a crucial point for the estimation of the radiobiological parameters on which are based the current treatment planning[1] . Nowadays, the accuracy and approach for the LET calculation can significantly affect the reliability of the calculated Relative Biological Effectiveness(RBE)[2] . The LET is not a physical quantity that can be easily measured, and therefore, values are usually estimated by calculating stopping power based on the Bethe-Bloch equation. Its definition, as reported in ICRU Report No.85, is related to a non-stochastic quantity that describes the average energy transfer from electronic interactions per unit length travelled by charged primary particles. The Monte Carlo(MC) technique is the most accurate method to account for complex radiation transport effects and energy losses in a medium.However, as a computation method, the accuracy and precision of the MC calculation results strongly depend on the physics interaction cross sections applied as well as on the simulation algorithms used and the transport parameters chosen[3] . The main aim of this study was to develop a completely open source tool based on Geant4 code for the calculation of the LET-track and LET-dose distributions of therapeutic proton and ion beams.Furthermore, the main parameters that can influence the LET calculation in a typical MC simulation based on a voxelized equivalent tissue phantom, were identified and investigated. Particular attention was given to the energy loss process due to the electronic interactions such as ionization and excitation of the primary incident particles and to the production cut and step dependence.Moreover, the secondary nuclei generation was considered and opportunely weighted to the computational total-LET-dose calculation.A module to couple the MC calculation to LEM radiobiological model has been studied and a series of calculations were performed to illustrate the impact of different LET values on the RBE-weighted dose.