Accelerator neutron sources for BNCT: Current status and some pointers for future development

Stuart Green; Ben Phoenix; Satoshi Nakamura; Yuan Hao Liu; Diyun Shu; Naonori Hu; Shunsuke Suzuki; Hanna Koivunoro; Hiroaki Kumada; Hiroki Tanaka

doi:10.1016/j.apradiso.2025.111656

Accelerator neutron sources for BNCT: Current status and some pointers for future development

Appl Radiat Isot. 2025 Jan 3:217:111656. doi: 10.1016/j.apradiso.2025.111656. Online ahead of print.

Authors

Stuart Green¹, Ben Phoenix², Satoshi Nakamura³, Yuan Hao Liu⁴, Diyun Shu⁴, Naonori Hu⁵, Shunsuke Suzuki⁶, Hanna Koivunoro⁷, Hiroaki Kumada⁸, Hiroki Tanaka⁹

Affiliations

¹ School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, UK; Department of Medical Physics, University Hospital Birmingham NHS Trust, Edgbaston, Birmingham, B15 2TH, UK. Electronic address: stuart.green@uhb.nhs.uk.
² School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, UK.
³ Division of Radiation Safety and Quality Assurance, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan.
⁴ Neuboron Medical Group, Xiamen Humanity Hospital BNCT Center, Xiamen, China.
⁵ Kansai BNCT Medical Center, Osaka Medical and Pharmaceutical University, 2-7 Daigaku-machi, Takatsuki-shi, Osaka, 569-8686, Japan.
⁶ Department of Medical Physics, Shonan Kamakura General Hospital, 1370-1 Okamoto, Kamakura-City, Kanagawa, 247-8533, Japan.
⁷ Neutron Therapeutics Finland Ltd, Helsinki, Finland.
⁸ Faculty of Medicine, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, 305-8575, Japan.
⁹ Particle Radiation Oncology Research Center, Institute for Integrated Radiation and Nuclear Science, Kyoto University, 2-Asashiro-Nishi, Kumatori-cho, Sennan-gun, Osaka, 590-0494, Japan.

PMID: 39805180
DOI: 10.1016/j.apradiso.2025.111656

Abstract

Recent decades have seen the development of accelerator neutron sources suitable for installation in a hospital setting. Numerous challenges have been faced and solved to deliver technology which continues to transform the field of BNCT. This paper begins by briefly reviewing the technologies which are currently, or soon will be, in clinical use. This is followed by discussion of the thermal neutron fluence distributions produced by these accelerator sources and their associated beam shaping assemblies. This is illustrated by basic physics simulations of monoenergetic neutron fields, followed by some broad comparisons of the published distributions of thermal fluence produced by the different available technologies. It will be argued that these distributions have a high degree of similarity and that this similarity that can be helpful as the field of BNCT matures. Finally some aspects of the design of beam shaping assemblies and beam collimation will be discussed, and how this may enhance the capability of BNCT for verification of the delivered dose via the measurement of the prompt gammas emitted by the ¹⁰B (n, alpha) ⁷Li reaction. In particular the directionality of the beam will be discussed and measures that those designing beam shaping assemblies might consider to increase/improve beam directionality.