Development of DOI Detector for PET using Different Kinds of Reflectors

We developed a depth of interaction (DOI) detector for positron emission tomography (PET) using different kinds of reflectors. The detector module consists of two layers of scintillator arrays, which was composed of 4 × 4 Gadolinium Aluminum Gallium Garnet (GAGG) crystals of size 3 mm × 3 mm × 10 mm, and 4 × 4 silicon photomultiplier (SiPM) arrays. The bottom layer optically coupled to the SiPM used a diffuse reflector and the top layer used a specular reflector. The layer interacted with gamma ray and crystal could be determined by analyzing the signal size because it obtained for each layer is different by using different reflectors for the crystals for each layer. The detector performance was analyzed by the flood image, energy spectrum with two photoelectric peaks, and energy resolution. In the experiment for the detector module performance, all pixels in the flood map were well decoded, and the energy spectrum of each pixel is measured with two photo peaks.