Non-invasive quantification of F-florbetaben with total-body EXPLORER PET.

Purpose: Kinetic modeling of F-florbetaben provides important quantification of brain amyloid deposition in research and clinical settings but its use is limited by the requirement of arterial blood data for quantitative PET. The total-body EXPLORER PET scanner supports the dynamic acquisition of a full human body simultaneously and permits noninvasive image-derived input functions (IDIFs) as an alternative to arterial blood sampling. This study quantified brain amyloid burden with kinetic modeling, leveraging dynamic F-florbetaben PET in aorta IDIFs and the brain in an elderly cohort.

Methods: F-florbetaben dynamic PET imaging was performed on the EXPLORER system with tracer injection (300 MBq) in 3 individuals with Alzheimer's disease (AD), 3 with mild cognitive impairment, and 9 healthy controls. Image-derived input functions were extracted from the descending aorta with manual regions of interest based on the first 30 seconds after injection. Dynamic time-activity curves (TACs) for 110 minutes were fitted to the two-tissue compartment model (2TCM) using population-based metabolite corrected IDIFs to calculate total and specific distribution volumes (V, V) in key brain regions with early amyloid accumulation. Non-displaceable binding potential () was also calculated from the multi-reference tissue model (MRTM).

Results: Amyloid-positive (AD) patients showed the highest V and V in anterior cingulate, posterior cingulate, and precuneus, consistent with analysis. and V from kinetic models were correlated (r = 0.46, P<2) with a stronger positive correlation observed in amyloid-positive participants, indicating reliable model fits with the IDIFs. V from 2TCM was highly correlated ( = 0.65, P< 2) with Logan graphical V estimation.

Conclusion: Non-invasive quantification of amyloid binding from total-body F-florbetaben PET data is feasible using aorta IDIFs with high agreement between kinetic distribution volume parameters compared to in amyloid-positive and negative older individuals.