• bgo
• monolithic
• pet
• time-of-flight

Time-of-flight (TOF) PET was initially introduced in the early days of PET and is now a clinical standard procedure. Thanks to the introduction of fast scintillating crystals and SiPMs the time resolution of modern TOF-PET scanners is now approaching 200 ps at the expenses of a spatial resolution still in the range of 3-4 mm. This thesis is done in the framework of the UTOFPET project and explores novel detector designs based on monolithic crystals for uncompromized performance. In fact a monolithic crystal based detector could potentially improve sensitivity without compromising timing resolution thanks to its depth-of-interaction (DOI) estimation capabilities. In the context of the UTOFPET project, the aims of this thesis are: (1) to investigate the performance limits of monolithic crystals in PET focusing on algorithms that can actually be implemented in a PET detector; (2) to characterize a PET detector that is able to answer the challenges of both TOF-PET and total-body PET. A major part of the work is done via Monte Carlo simulations to predict the performance of detector solution tailored to total-body PET applications. A silicon photomultiplier (SiPM) simulation model is used to investigate the timing capabilities of monolithic crystals read by SiPM arrays. An original algorithm, based on neural network, for simultaneous estimation of event timestamp and position is also tested, achieving above-state-of-the-art results in both timing resolution and spatial resolution.