Preliminary characterization of a CdZnTe photon detector for BNCT-SPECT

The effectiveness of Boron Neutron Capture Therapy (BNCT) treatment depends on the amount of radiation dose deposited locally by the reaction 10B(n,α)7Li in the tumour; however, the local and real time measurement of this quantity during the neutron irradiation is a big challenge. To evaluate the dose it is necessary to know the spatial distribution of the 10B concentration and thermal neutron flux in the tissue during the irradiation. One technique to solve this problem relies on the on-line detection of the 478 keV 7Li de-excitation photons that can be used to map the spatial distribution of the reaction rate of the 10B(n,α)7Li. The present work has been developed within a project aiming to develop a Single Photon Emission Computed Tomography (SPECT) system based on CdZnTe (CZT) semiconductor detector. This work studied the performances of a 5×5×20mm3 CZT prototype detector focusing on the energy resolution and detection efficiency inside the energy range 200–1400 keV. The energy resolution at 478 keV is ∼3% and the detection efficiency is around 6%. These preliminary results confirms the feasibility of a CZT detector as a sensitive unit for a BNCT-SPECT imaging system.