Timepix3-based detector: a novel approach for evaluating \(^{10}\)B concentration and spatial distribution in boron neutron capture therapy

In boron neutron capture therapy (BNCT) research, precisely determining the concentration and distribution of \(^{10}\)B is essential for optimizing treatment efficacy. Over the years, various methods have been developed to measure these two quantities; in particular, at the University of Pavia, two primary techniques have been used: alpha spectrometry to quantify the concentration of \(^{10}\)B and neutron autoradiography to image its distribution. However, both methods have notable limitations. Alpha spectrometry returns the mean bulk \(^{10}\)B concentration and requires a quite complex process to correct the mean \(^{10}\)B concentration in the case of a heterogeneous sample. However, neutron autoradiography results in sample destruction and generally requires long processing times to obtain the concentration measure. To overcome these limitations, this work introduces an innovative method based on Timepix3 (TPX3) detectors. This method employs a TPX3 quad detector, which provides high spatial and temporal resolution, enabling the simultaneous measurement of both quantities down to tissue samples and cell pellets during the same irradiation session. This ensures real-time imaging of the 2D boron distribution. Experimental measurements were performed at the Laboratory of Applied Nuclear Energy (L.E.N.A.) of the University of Pavia, using biological tissue samples and the highly thermalized neutron beam from the Prompt Gamma Neutron Activation Analysis (PGNAA) facility housed at the Pavia TRIGA Mark II research nuclear reactor. The results demonstrated a high sensitivity to evaluate the distribution of \(^{10}\)B at boron concentrations slightly above those commonly found in tissues treated with BNCT. Consequently, the presented system deserves attention and further study as a potentially valuable tool in BNCT research. It shows great promise at both the basic and the preclinical levels, where it can contribute to the development of new boronated compounds, and in the clinical setting, where it can help optimize the treatment plan. The system provides essential information on the quantity and distribution of the capture agent obtained in a short time frame, without the need to destroy the sample subjected to analysis.