Abstract
PURPOSE: Before utilising preclinical Position Emission Tomography (PET) systems for biological studies, evaluating their performance is important to better qualify the scanner's applications. This study aims to assess the performance of the new extended field of view (FOV) nanoScan® PET/CT P123S system, developed for rodent total-body PET applications. METHODS: Scanner resolution, noise equivalent count rate (NECR), sensitivity and image quality were evaluated following NEMA NU-4 2008 protocols. Furthermore, a Derenzo phantom and linearity measurements were conducted. In vivo studies were subsequently carried out to evaluate system performance in biological applications. RESULTS: The scanner spatial resolution according to the NEMA protocol was 1.4 mm using FBP reconstruction, while with iterative reconstruction it was under 0.7 mm. The NECR peak using a 250‒750 keV energy window was 1805.0 kcps at 93.7 MBq and 880.7 kcps at 88.4 MBq for the mouse-sized and rat-sized phantom respectively. The absolute sensitivity was 10.5%. The standard deviation of the uniform area of the image quality phantom was 1.8%, while the recovery coefficients varied between 0.23 and 1.00. The spill-over ratios were 0.04, and 0.04 in the water and air-filled chambers respectively. Quantitative bias was < 4% with a linear response up to 105 MBq. Total-body rat images were successfully acquired using the new system. CONCLUSION: The new extended FOV PET system has improved sensitivity and count rate performance compared with previous systems. Its spatial resolution and quantitative accuracy are well-suited for preclinical PET applications. The extended FOV enables total-body imaging of both mice and rats.