Performance evaluation of a dedicated brain PET scanner with octagonal detector arrangement using a modified NEMA NU2 2018 protocol

BACKGROUND: This work presents the NEMA NU2 2018 performance evaluation of the NeuroLF Basic, a compact and fully integrated brain positron emission tomography (PET) system based on 10-mm-long LYSO crystals. PURPOSE: The goal is to assess its quantitative performance and imaging capabilities for neuroimaging applications. METHODS: The evaluation includes measurements and simulations of spatial resolution, scatter fraction, noise equivalent count rate (NECR), accuracy of corrections, image quality, and sensitivity, following standardized protocols to ensure reliable and reproducible results. In addition, imaging of the Hoffman 3-dimensional brain phantom was performed to visually evaluate system performance. Image quality was assessed using an ACR Esser phantom, which fits within the compact bore of the NeuroLF scanner. RESULTS: The average filtered-back-projection spatial resolution, measured at 1 and 10 cm radial offsets, was 2.51 and 3.61 mm, respectively, highlighting the system's ability to capture details essential for neuroimaging. The scatter fraction was 24.2% at the peak NECR, reflecting the system's capability to minimize scattered events. The peak NECR was 55.3 kcps at an activity concentration of 8.1 kBq/mL, demonstrating the system's efficiency in handling typical neuroimaging count rates. NeuroLF showed excellent accuracy of corrections at 3.7% and good image contrast for hot vials in a warm background in the adapted image quality procedure with the ACR Esser phantom, achieving values of 87.5%, 77%, 60%, and 35.8% for 25-, 16-, 12-, and 8-mm-diameter vials, respectively, with a maximum background variability of 10% for the 8-mm vial. Sensitivity, evaluated using a 70-cm line source, was 5.85 cps/kBq at the center of the field of view and 8.08 cps/kBq at a 10 cm radial offset. Images of the Hoffman phantom further demonstrated the system's ability to produce realistic brain uptake distributions. The measured NEMA NU2 2018 results showed good agreement with Monte Carlo simulation results, validating the simulated NeuroLF model for future research and optimization. CONCLUSIONS: These results demonstrate the NeuroLF's potential to deliver high-quality images, good detection efficiency, and robust quantitative performance. The comprehensive NEMA NU2 2018 evaluation, supported by Hoffman phantom imaging, confirms NeuroLF's capability as a valuable tool for clinical applications in neuroimaging.