A side-by-side LYSO/GAGG phoswich detector aiming for SPECT imaging

Single photon emission computed tomography (SPECT) is an effective metabolic and functional imaging technique in both clinical and pre-clinical applications. Gamma-ray detector is a key component of a SPECT system. High performance detectors are required for high-quality SPECT imaging. In this paper, a detector using a side-by-side LYSO/GAGG phoswich array read out by a sparse 8 x 8 SiPM array is developed. The phoswich crystals are discriminated using pulse waveform integration to peak ratio. A Tc-99m and a Co-57 source irradiation experiments were conducted. Results of the experiments demonstrate that the LYSO and GAGG can be clearly discriminated using the simple parameter. 12 x 12 of both LYSO and GAGG crystal arrays with a crystal size of 1.35 x 2.7 x 7 mm(3) could be successfully distinguished. The average energy resolutions @140 keV of 12 x 12 LYSO crystals and 12 x 12 GAGG crystals are 26.23% and 21.29%, respectively. The calculation and experiment verifies that the side-by-side LYSO/GAGG phoswich detector achieves relatively high resolution and high sensitivity which is suitable for high performance SPECT systems.