Validation of IAEA Electron Beam Data for Radiotherapy and Their Use to Model Total Skin Irradiation

Monte Carlo simulation for external beam radiotherapy requires precise modeling of the treatment linear accelerator head and of the primary electron beam. Detailed modeling of medical accelerators is complex and could require proprietary data, and the production of an adequate sample of primary particles to simulate statistically significant dosimetric observables requires intensive computational resources. To facilitate these tasks, IAEA (International Atomic Energy Agency) released a phase-space database for external beam radiotherapy, consisting of primary particle distributions deriving from Monte Carlo simulations of widely utilized linear accelerators, which can be used as input to dosimetric simulations. The IAEA data have been released more that 10 years ago along with a Geant4 interface. This presentation addresses the ability to produce realistic dosimetric distributions in Geant4-based simulations using IAEA electron beam data and to endeavour the simulation of beams for nonconventional radiotherapy settings that are not covered by the IAEA database, such as those needed for Total Skin Irradiation (TSI, as performed in Total Skin Electron Therapy procedures). We report the results of validation tests, involving the comparison of dosimetric quantities measured in quality control standard procedures and simulated with Geant4 using IAEA phase-space data.