Predicted performance of a PG-SPECT system using CZT primary detectors and secondary Compton-suppression anti-coincidence detectors under near-clinical settings for boron neutron capture therapy

A test version of a prompt-gamma single photon emission computed tomography (PG-SPECT) system for boron neutron capture therapy (BNCT) using a CdZnTe (CZT) semiconductor detector with a secondary BGO anti-Compton suppression detector has been designed. A phantom with healthy tissue region of pure water, and 2 tumor regions of 5 wt% borated polyethylene was irradiated to a fluence of 1.3 × 109 n/cm2. The number of 478  keV foreground, background, and net counts were measured for each detector position and angle. Using only experimentally measured net counts, an image of the 478  keV production from the 10B(n,α)7Li* reaction was reconstructed. Using Monte Carlo simulation and the experimentally measured background counts, the reliability of the system under clinically accurate parameters was extrapolated. After extrapolation, it was found that the value of the maximum-value pixel in the reconstructed 478  keV γ-ray production image overestimates the simulated production by an average of 9.2%, and that the standard deviation associated with the same value is 11.4%.