As previously demonstrated, an excellent timing resolution below 100 ps FWHM is possible in time-of-
flight positron emission tomography (TOF PET) if the detection method is based on the principle of
detecting photons of Cherenkov light, produced in a suitable material and detected by microchannel
plate photomultipliers (MCP PMTs). In this work, the silicon photomultipliers (SiPMs) were tested for the
first time as the photodetectors in Cherenkov TOF PET. The high photon detection efficiency (PDE) of
SiPMs led to a large improvement in detection efficiency. On the other hand, the time response of currently
available SiPMs is not as good as that of MCP PMTs. The SiPM dark counts introduce a new source
of random coincidences in Cherenkov method, which would be overwhelming with present SiPM
technology at room temperature. When the apparatus was cooled, its performance significantly
improved.