26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Recent developments in the Geant4 Monte Carlo Simulation Toolkit for medical physics applications

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Focus session talk AIP | Nuclear and Particle Physics (NUPP)

Description

Geant4 is a widely used open-source Monte Carlo toolkit for the simulation of particle interactions with matter, with extensive applications in medical physics, including radiotherapy, nuclear medicine, medical imaging and radiation protection. In this context, developments within the Geant4 Collaboration are aimed to extend functionality and improve the accuracy of physics models for medical physics, to respond to the needs of the scientific community.

This presentation reports recent advances in Geant4 physics modelling for medical physics applications.

In electromagnetic physics, updated data libraries (including ICRU90 and EPICS2017) improve the description of charged particle transport and photon interactions. In hadrontherapy applications, improvements in ion electromagnetic interaction modelling via the implementation of the Lindhard-Sorensen ion model, are demonstrated through comparisons with experimental data. The recently introduced Light Ion Quantum Molecular Dynamics (LiQMD) model shows consistently better agreement with experimental measurements when compared to other Geant4 nuclear fragmentation models.

Advances in low energy neutron transport include improved treatment of thermal scattering and updated data libraries, improving the reliability of simulations relevant to radiation protection and detector design. Ongoing developments target nuclear cross-section modelling for isotope production, with the implementation of IAEA-evaluated datasets in the Geant4 HP data libraries.

At the microscopic scale, Geant4-DNA has been extended to support multi-scale simulations, from physical interactions to chemical processes and biological damage. Recent developments combine Geant4 condensed history approach physics with track-structure models below ~300 MeV/u, important for hadron therapy applications. Work in progress includes the improvement of the chemical stage modelling for high dose rates and longer time scales.

These developments are supported by an extensive validation program performed by the Geant4 Medical Simulation Benchmarking Group.

Overall, the results demonstrate that recent Geant4 developments provide improved accuracy for medical physics applications. Future work will further expand physics capabilities to meet emerging clinical and research requirements.