Experimental evaluation of a SPECT module for prompt gamma-based dose monitoring in Boron Neutron Capture Therapy

Boron Neutron Capture Therapy (BNCT) is an advanced cancer treatment that combines radiation therapy with targeted drug delivery. It is promising for treating tumors that are challenging to address with conventional methods, but requires precise dose monitoring to work effectively. This can be achieved by detecting the prompt 478 keV gamma rays produced by boron neutron capture reactions during irradiations. In this work, we present experimental measurements performed with a single-unit SPECT module based on a new version of the BeNEdiCTE detector. The detector uses a LaBr3(Ce, Sr) monolithic crystal read out by silicon photomultipliers and custom electronics. To minimize background contribution, the new version of the BeNEdiCTE detector features electronic boards realized with a boron-free material and a new case in Teflon. It also features reduced dead time, enabling reliable operation under high neutron flux conditions. We analyzed background and evaluated the impact of various detector materials and shielding configurations at the Laboratorio di Energia Nucleare Applicata (LENA) in Pavia, Italy. We detected boron concentrations down to 250 ppm in a volume of 5 mL during measurements with a neutron flux of 3.14×106ncm−2s−1. We also performed tomographic measurements by rotating the SPECT module at four different angles around the sample. We successfully detected the boron signal at all angles and reconstructed a 3D image of a couple of vials with a spatial resolution better than 1 cm. These results demonstrate the potential of the BeNEdiCTE detector for real-time monitoring of boron distribution during BNCT.