A test of silicon photomultipliers as readout for PET

The silicon photomultiplier (SiPM) is a novel photon detector based on Geiger mode operating avalanche photodiodes. In this paper, we present results from a test, demonstrating the feasibility of SiPM as readout elements in scintillator-based positron emission tomography (PET). As scintillator we use the newly developed LYSO crystals having similar characteristics as LSO. With our setup we measure an energy resolution of about 22% and a time resolution of a single crystal element of (1.51±0.07)ns, both full-width at half-maximum. A significant improvement in time resolution could be achieved by triggering on the first photoelectron in the signal. We also present the coincidence rate of two detector channels vs. the position of a small point-like 22Na positron source.