Review of the geometrical developments in GEANT4-DNA: From a biological perspective

GEANT4-DNA is an expansion of the widely utilised GEANT4 Monte Carlo toolkit. This extension focuses on modelling the physical, chemical, and biological stages of ionising radiation for radiobiological applications at cellular and DNA level interactions. To date, review papers on GEANT4-DNA focus solely on evaluating a selection of the latest developments with a greater focus on mechanistic developments rather than progress in biologically specific geometries. In this work, an overview of biological analysis and biological geometries that have been developed are discussed, highlighting the latest developments and future possible development avenues for GEANT4-DNA for this application. An overview of the biological organisation levels, namely DNA, cellular, and population levels, and how GEANT4-DNA models the physical, chemical, and biological processes are also described. This review emphasises the need for persistent development of specific biological geometry accompanied by personalised DNA damage analysis parameters dependent on the biological processes considered within a specific model. It also provides an in-depth understanding of the advances at all the biological organisation levels (DNA, cellular, and population) and the use of co-operative platforms developed to model alongside GEANT4 to provide further detailed geometries and or biological damage analysis. The developments presented have been analytically discussed along with their key findings and prospects for GEANT4-DNA. Finally, a perspective on future necessary developments is portrayed since many of the advancements in the biological analysis and biological geometries discussed have not been exploited to their full potential. The development of GEANT4-DNA, using the advances discussed in this review, provides a favourable method for the evaluation of biological damage comparable to radiobiological studies.