Comparison of SDDs and SiPMs photodetector options for INSERT, a new multi-modality SPECT/MRI system for preclinical and clinical imaging

A new multi-modality imaging tool is under development in the framework of the INSERT (INtegrated SPECT/MRI for Enhanced Stratification in Radio-chemoTherapy) project, supported by the European Community. A custom SPECT apparatus, used as an insert for commercially available MRI systems, will enhance the treatment of brain tumors (primarily glioma) by offering more effective and earlier diagnosis with potentially better outcome in survival. The project aims to develop two SPECT prototypes, dedicated to preclinical and clinical imaging. The final goal is to fit the complete SPECT detection system into an existing MRI bore (diameter: 20 cm for the preclinical system and 59 cm for the clinical system). In this work, we propose the use of two possible photodetecors for the scintillator readout: Silicon Drift Detectors and Silicon PhotoMultipliers. A comparison between the main parameters of the two technologies as well as simulations about the achievable energy and spatial resolution are presented