Investigation of a Next Generation Medical Imaging SiPM Technology

Scintillation detectors based on silicon photomulitpliers (SiPM) have led to performance advances in both medical imaging and high energy physics applications. The performance of SiPM devices is of particular interest in the field of positron emission tomography (PET) where time-of-flight (TOF) information can be used to improve PET reconstruction image signal-to-noise ratio. Key to TOF performance is the coincidence time resolution (CTR), which for a PET system is determined by several factors including the properties of the scintillation crystals, the speed, noise and photon detection efficiency (PDE) of the SiPM device, as well as the readout electronics. Additionally, better energy resolution improves timing measurements as well as the system’s ability to reject scattered photons. This report characterizes the CTR and energy resolution of cutting-edge SiPM technology. Coincidence measurements were taken from a
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Na source using two detectors comprising 3×3×3 mm
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LYSO crystals wrapped in Teflon reflector tape and coupled via optical grease to pairs of new SiPM devices of varying properties. From the measurements taken, the best CTR for the next generation SiPM devices is 95.3 ps (± 1.5 ps standard error), which is a significant improvement over comparable J-series devices that measured 105.2 ps (± 1.6 ps standard error). Additionally, the energy resolution at 511 keV was measured to be 11.7% (± 0.8%) for the next generation SiPM devices as compared to 13.4% (± 0.8%) for the J-series device.