Abstract
<jats:p>Boron Neutron Capture Therapy (BNCT) consists on the selective accumulation of boron-10 in tumor cells and targeted neutron irradiation. A critical challenge for clinical implementation is the accurate real-time measurement of the absorbed boron dose. This study presents the first application of prompt γ-ray spectroscopy to evaluate boron uptake and clearance dynamics during BNCT in a cohort of ten pets with spontaneous tumors. The research was conducted at an accelerator-based neutron source using a high-purity germanium γ-spectrometer, shielded and positioned to detect 478 keV photons emitted during the boron neutron capture reaction. The method successfully allowed for the direct, non-invasive monitoring of boron concentration within the irradiation volume. Results demonstrated significant inter-subject variability, with the intensity of capture reactions differing by a factor of 10 and boron clearance times varying by a factor of 6 among the animals. Crucially, the study established that the measured intensity of boron neutron capture events did not correlate with either tumor volume or boron concentration in the blood. Furthermore, boron clearance from tumors (3–17 hours) was notably slower than that from blood (1–3 hours). These findings indicate that relying solely on blood analysis for treatment planning is insufficient. Consequently, the integration of prompt γ-ray spectroscopy is strongly recommended for clinical BNCT to ensure precise dosimetry, optimize treatment duration, and improve outcome assessment.</jats:p>