EPJ Plus Highlight - A better model for effective neutron capture therapy

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Published on 19 December 2025

Accounting for multiple neutron production mechanisms, the model makes safe neutron-based cancer treatments easier to control

Boron Neutron Capture Therapy (BNCT) is an innovative technique for treating tumours that are non-operable, or resistant to more conventional treatments. To exploit BNCT’s potential at its best, a neutron beam with suitable energy and angular distributions is needed. Nowadays, proton accelerators coupled to lithium or beryllium targets are widely used as neutron sources, but so far, the yields of neutrons produced by the beryllium target, which is the safest and most controllable of the two, have proven difficult to calculate.

Through new research published in EPJ Plus, Alessandro Colombi and colleagues at Italy’s National Institute for Nuclear Physics have developed a new model for proton-BNCT, which can more accurately calculate the neutron beams produced when protons are fired into a thick beryllium-9 target. Their model could ultimately lead to more reliable techniques for treating malignant tumours.

In BNCT, a patient is first injected with a boron-containing compound which preferentially accumulates inside tumour cells. They are then irradiated with beams of low-energy neutrons, which are captured by stable boron-10 isotopes in the compound. The resulting reaction produces secondary radiation in the form of helium and lithium nuclei, which are toxic to living tissues, but only deposit their energy over distances comparable to the size of a single cell. This limits any damage to surrounding healthy tissues, making the technique more selective than many other radiotherapy techniques.

For a safe and effective treatment, a correct description of the neutron source is essential, allowing clinicians to accurately assess the dose administered to the patient. In the beryllium case, the target produces neutrons through several different reaction mechanisms, making it difficult to calculate neutron beam angles and energies.

In their study, Colombi’s team developed a new description for the reaction channels firmly based on the few available experimental data. Neutron energy and angle distributions were validated up to 5 MeV, with initial dosimetric evaluations performed using the model as a neutron source in a realistic BNCT setup.