Imaging Performance of the Fully Assembled Ultra-High Resolution (UHR) Brain PET scanner

High spatial resolution is needed to resolve small structures in the brain and to enable imaging of neurological pathways at the onset of diseases. The Ultra-High Resolution (UHR) brain PET scanner can be key in the quest for brain PET imaging with finer precision. We report the latest measurement results obtained with the now fully-assembled UHR scanner having an axial field-of-view of 235 mm. The UHR scanner is based on the LabPET II modular technology platform employing a truly pixelated detector readout scheme to achieve superior spatial resolution. Ultrahigh resolution is confirmed with 87% resolvability of 1 mm rods and fully resolved larger rods (≥1.35 mm) of the Ultra-Micro Hot Spot phantom. A lower partial volume effect with the UHR leads to good measured contrast recovery both for the NU 4 and NU 2 image quality phantoms as well as excellent image quality and substructure resolvability of the 3D Hoffman brain phantom. Peak noise-equivalent count rate of 10.3 kcps was measured at 21.6 kBq/ml. This set of measurements thus completes the physical and imaging characterization of the UHR scanner, showing possibilities towards the identification of small-scale structures implicated in brain disorders and neurodegenerative diseases.