A verification-oriented review of reaction-enhanced radiotherapy: linking nuclear data, transport modeling, and measurable observables

Clinical Snapshot

Key Findings

• P Value: Not reported

• Effect Size: Not applicable — no quantitative clinical effect size reported; review is methodological and physics-oriented

• Primary Outcome: Conceptual verification framework for reaction-enhanced radiotherapy (RER), establishing that clinically credible RER requires coordinated progress across four domains: uncertainty-aware nuclear data, detector-integrated transport modelling, isotope delivery and tumour-to-normal biodistribution assessment, and high-sensitivity radiation monitoring

• Nnt Or Sensitivity: Not applicable for this review type; the closest analogue is the identification of the 4.439 MeV prompt-gamma signal as a candidate observable for Proton-CAT verification, but detector sensitivity and specificity for this signal are noted as requiring further validation

• Confidence Interval: Not reported — physics uncertainty quantification (covariance matrices for nuclear data) discussed conceptually but no clinical confidence intervals presented

Clinical Application

BNCT: feasible at specialised centres with accelerator-based neutron sources; requires boron-10 compound delivery (e.g., boronophenylalanine) and specialised dosimetry. PBCT: currently constrained by narrow resonance windows, low reaction yield, and limited real-time observability — not clinically feasible at present. Proton-CAT: highly experimental; requires nitrogen-15 isotope delivery, proton beam infrastructure, and validated prompt-gamma detection systems — clinical feasibility is years away. The verification framework proposed is a research roadmap rather than an immediately implementable clinical protocol. Australia has limited but growing particle therapy infrastructure. The Australian Bragg Centre for Proton Therapy and Research (Adelaide) opened in 2024 and represents the primary proton therapy facility. BNCT is not currently available in Australia through TGA-approved pathways, and boronophenylalanine (BPA) does not have PBS listing. The TGA has not approved any RER modality beyond conventional proton therapy. RACGP and RANZCR guidelines do not currently address BNCT or emerging RER modalities. Australian oncologists and radiation physicists should monitor this field, particularly BNCT developments, as international evidence matures. The verification framework described is relevant to Australian medical physics research programs and future facility planning, but has no immediate PBS or clinical guideline implications. Patients seeking BNCT currently require overseas referral, typically to Japan or Europe. Patients with solid tumours being considered for advanced particle therapy, particularly those where conventional photon or proton therapy offers suboptimal therapeutic ratios. Most immediately relevant to BNCT candidates (e.g., recurrent head and neck cancer, glioblastoma multiforme) where clinical evidence is most mature. PBCT and Proton-CAT remain experimental and are not yet applicable to routine clinical populations.

Abstract

Reaction-enhanced radiotherapy (RER) aims to improve the therapeutic ratio of particle therapy by exploiting isotope-specific nuclear reactions that generate localized high-linear energy transfer secondary radiation. Absorbed dose remains the central metric for radiotherapy planning and evaluation; however, RER introduces additional verification requirements related to nuclear-reaction data, mixed-field transport, isotope delivery, and measurable secondary-field observables. This review frames RER as a verification-oriented physics problem built on three interdependent pillars: covariance-aware nuclear data, high-fidelity Monte Carlo transport, and reaction-specific secondary-field monitoring. Boron neutron capture therapy (BNCT) is treated as the clinically mature benchmark for RER, whereas PBCT and the emerging15N(p,α)12C-based proton-carbon-alpha therapy (Proton-CAT) are discussed as early-stage comparative cases. BNCT has the strongest clinical evidence base, while PBCT remains constrained by narrow resonances, low reaction yield, and limited observability. Proton-CAT provides a candidate 4.439 MeV prompt-γobservable whose verification value still requires detector-level validation and delivery/selectivity assessment. Overall, clinically credible RER requires coordinated progress in uncertainty-aware nuclear data, detector-integrated transport modeling, isotope delivery and tumor-to-normal biodistribution assessment, and high-sensitivity radiation monitoring for therapy verification.

References

1. 1.An, D., Dong, L., Sun, Z., Wu, J., Wang, T., Kang, J., He, Z., & Hu, Z. (2026). A verification-oriented review of reaction-enhanced radiotherapy: linking nuclear data, transport modeling, and measurable observables. Biomedical Physics & Engineering Express. https://doi.org/10.1088/2057-1976/ae81bd