Quimera: a computer system based on code Geant4 for dose assessments in radiotherapy

The objective of this work is to show the development methodology of a computer system, called Quimera, based on Monte Carlo (MC) code Geant4 for dose assessments in radiotherapy. Quimera consists of a graphical user interface (qGUI) and three MC applications (qLinacs, qMATphantoms and qNCTphantoms). The qGUI has interface function for the MC applications by creating or editing input files, running simulations and analyzing results. The MC applications were built using Geant4 and consist of two types: generation of phase spaces of a Linac model (qLinacs) and dose assessments from a phase space in computational phantoms, mathematical phantoms (qMATphantoms) or NCT phantoms - built from computed tomography images (qNCTphantoms). The qMATphantoms is aimed for modeling of physical phantoms used in quality control of Linacs. The qNCTphantoms is aimed for treatment planning and quality control of treatment planning systems. In this first version, Quimera can be used for research, planning of simple treatments and quality control in photon beam radiotherapy. The Quimera’s MC applications run independent of the qGUI and the qGUI can be used for result analysis from other MC applications.