Performance evaluation of the LabPET12, a large axial FOV APD-based digital PET scanner

The LabPET12 is the latest version of LabPET¿ avalanche photodiode (APD)-based digital scanners, having an 11.4 cm axial field of view and 9216/4608 crystals/electronic readout channels to achieve high sensitivity and count rate performance, while preserving the same very high spatial resolution. Its performance characteristics have been thoroughly investigated largely based on the new NEMA NU4 - 2008 small animal PET standard. Average energy resolution is 20±3% for LYSO and 19±3% for LGSO. After timing alignment, the overall FWHM timing resolution is 7.1/8.3/9.2 ns for LYSO/LYSO, mixed and LGSO/LGSO coincidences. Imaging performance was assessed using various energy windows with lower threshold from 100 to 350 keV. Sensitivity varied from 8 to 2.8%, between 100 and 350 keV. With the lower threshold set at 200 keV, peak NEC count rates were 449 kcps at 66 MBq and 179 kcps at 81 MBq for the mouse and rat NEMA phantoms, respectively. Two acquisition modes were investigated, a high sensitivity and high resolution mode. Whole-body static images of mice were obtained with Na¹⁸F. In conclusion, the LabPET12 provides excellent dynamic performance with shorter imaging time or lower injected radioactivity while achieving the same exquisite spatial resolution as the LabPET4 and LabPET8 scanners.