An Investigation Into the Use of Geiger-Mode Solid-State Photomultipliers for Simultaneous PET and MRI Acquisition

Photon detecting Geiger-mode solid-state devices are being actively researched and developed because, unlike photo- multiplier tubes (PMT), they can be used in high-magnetic-field and radio-frequency environments, such as in magnetic resonance imaging (MRI) scanners. In addition, some Geiger-mode solid-state devices have higher photon detection efficiencies than PMTs and higher gains than avalanche photo-diodes (APD). We tested Geiger-mode solid-state photomultipliers (SSPM) inside a 3 T MRI to study the possibility of using them in combined PET/MRI scanners. Approximately 16% energy resolutions and ~1.3 ns coincidence time resolutions with ²²Na and lutetium yttrium oxyorthosilicate (LYSO) were obtained for full-width at half maximum (FWHM) for T1, T2, and gradient echo T2* MRI pulse sequences with little MR image degradation. The study shows that SSPMs have excellent potential for use in combined PET/MRI scanners.