Speaker
Description
Accurate control of beam penetration depth is a fundamental requirement in hadrontherapy. Despite advanced treatment planning systems and high-quality imaging, residual uncertainties in Bragg peak positioning persist due to anatomical variability, conversion uncertainties, and intrinsic physical processes. Such deviations may lead to irradiation of healthy tissues beyond the target or underdosage of the tumor volume. Reliable and real time range verification techniques are therefore essential for the safe and effective delivery of particle therapy.
This study is carried out within the framework of the REALPATH project, funded by the Italian Ministry of University and Research, aimed at developing a real-time range monitoring system based on Prompt Gamma Imaging (PGI). The technique exploits the spatial correlation between the Bragg peak position and the emission profile of prompt gammas generated by nuclear interactions between the incident hadron beam and irradiated tissues.
A prototype PGI detection system was modelled using the FLUKA Monte Carlo code. The simulated setup includes a collimation stage coupled to a pixelated LYSO scintillator detector and positioned inside a treatment room geometry to account for room-scattered radiation. Proton beams at clinically relevant energies were considered. The energy spectra scored in the detector region were analyzed by separating the contributions of the different radiation components, with particular focus on the energy window relevant for PGI acquisition. The results demonstrate that the system is suitable for proton beam energies in the range 60–210 MeV, covering the clinically relevant interval for treatment delivery.
The neutron field within the treatment room was also characterized. Spectral analysis revealed thermal, epithermal, and fast components, including a high-energy contribution above 20 MeV. Based on these findings, different shielding strategies and configurations were evaluated to mitigate neutron-induced background in the detector signal.
Preliminary measurements show good agreement with simulations, supporting the feasibility of the proposed approach.