Advantages and pitfalls of the silicon photomultiplier (SiPM) as photodetector for the next generation of PET scanners

Silicon photomultipliers (SiPM) are a novel type of photodetectors that show great promise for nuclear medicine applications and especially for the next generation of PET scanners. The INFN collaboration DASIPM2 is investigating in depth the properties of the SiPM developed at FBK-irst (Trento, Italy), whose performance compete successfully with those of similar devices produced by commercial companies, but have in addition novel and attractive properties, such as monolithic matrix arrangement. In this paper we illustrate the advantages and pitfalls of the SiPM for PET applications. In particular we report on the most recent experimental results for SiPM and SiPM matrices performances: (i) an intrinsic very good time resolution that coupled to a high PDE could favor time-of-flight PET exploitation; (ii) very high photodetector granularity that allows position determination with continuous crystal and possibly stacking of several layers, i.e., Depth Of Interaction information capability thus paving the way for the construction for the next generation of PET cameras; (iii) MRI compatibility in magnetic field and magnetic field gradient, thus giving the possibility of constructing a state-of-the-art PET insert within an MRI scanner.