Recent Geant4 developments and applications in medicine and biology: Report from the 5th Geant4 International User Conference at the Physics-Medicine-Biology Frontier.

The Geant4 International User Conference at the Physics-Medicine-Biology Frontier is a conference series for Geant4 and Geant4-DNA users working in medical physics, radiation protection from environmental and space radiation, radiation biology, and related fields. Organized under the auspices of the Geant4 Collaboration (https://geant4.org), the series provides an opportunity for developers and users of Geant4 and Geant4-based tools to regularly gather and discuss recent advances. The fifth meeting in this series, the 5th Geant4 International User Conference at the Physics-Medicine-Biology Frontier (https://indico.rcnp.osaka-u.ac.jp/event/2096/overview), was held at the University of Osaka Nakanoshima Center, Japan, from 27 to 29 March 2024. Participants were invited to submit original articles for peer review in a special issue of Physica Medica (V Geant4 International User Conference Invited Papers: https://www.sciencedirect.com/special-issue/100KLKWDPF0), the European Journal of Medical Physics, which was fully dedicated to the event. Nine of the research projects presented at the conference were selected for publication. This introductory article provides an overview of the nine research papers included in this special issue, each offering unique perspectives and significant advancements to the overarching theme of the conference.