Comparison of CdZnTe Detector Design with NaI(T1) Gamma Cameras for an Adaptive Clinical SPECT/CT System with Full-Ring Detectors and Multi-Pinhole Collimators

We developed an adaptive SPECT/CT system with a full detector ring and 8 sets of multi-pinhole (MPH) collimators to provide optimal resolution-sensitivity combination for various clinical applications. To fully exploit its advantages and expand its capability in multi-isotope imaging studies, some semiconductor detectors, e.g. pixelated Cadmium Zinc Telluride (CdZnTe) detectors, were investigated for their superior energy resolution and compact size (negligible dead area). The next generation system would integrate nine CdZnTe modules with a 32-slice low dose CT while each module has a FOV of 52x24cm with 13x6 blocks. To thoroughly investigate the impacts of CdZnTe detectors on the system performance, various thicknesses of 2-5 mm and pixel sizes of 0.5 to 2.0 mm are evaluated under different operation conditions (applied voltages) in the comprehensive simulation. The side-by-side comparison of several CdZnTe detector configurations with the conventional NaI(TI) detectors in terms of the resolution, sensitivity and imaging performance are also tested.