First results of an ASIC controlled γ-detector based on a SiPM-array and a monolithic LYSO

We present the first results of an MR compatible PET system based on continuous crystals and SiPM detectors, along with a dedicated application-specific integrated circuit (ASIC) for the readout stage. The use of continuous scintillation crystals preserves the spatial distribution of scintillation light for each γ--ray impact, which can be reconstructed with a small number of statistical moments Therefore, it is possible to reduce the number of analogue-to-digital conversion channels. The current ASIC can measure up to 8 moments of the light distribution, providing information about the X and Y photon impact coordinates, photon energy, depth of interaction and other higher moments that can improve the position accuracy of the photon impact. SiPMs exhibit their best performance for reduce active areas, where the dark counts are minimized. An innovate coupling design between crystal and SiPM-array has been made in order to keep the compromise between reduced active areas and efficient collection of the scintillation light. SiPM detectors are also suitable to work in the presence of magnetic fields. Moreover, they could be integrated in a RF coil of the MRI system due to their reduced dimensions [1]. Experimental results show very promising possibilities for the system.