New myocardial SPECT system with CdZnTe semiconductor detectors

The purpose of our research is to develop a new myocardial single photon emission CT (SPECT) system with a semiconductor detector. The gamma camera with a semiconductor detector enables us to measure projection data with arbitrary angles because the detector is smaller than that in ordinary gamma cameras with a scintillation detector. We have proposed a new data acquisition method for a myocardial SPECT system, in which projection data were measured with angles at which the signal to noise ratio in projection data was relatively high. In this paper we evaluated the performance of the proposed system by simulations more accurately, by considering the attenuation of gamma rays and the aperture effect of the collimator. In addition, we developed an evaluation system with two semiconductor detectors to confirm the effect of the proposed method experimentally. In this system we used low energy high-resolution collimators. Each detector had twenty CdZnTe modules and the size of a module was 39 × 39 mm² (16 × 16 pixels). The thickness of the CdZnTe crystal was 5 mm. The results obtained with the simulations confirmed the validity of the proposed myocardial SPECT system. And the results of the experiments showed the fundamental performance of our proposed data acquisition system.