Simplifying [ 18 F]GE-179 PET: are both arterial blood sampling and 90-min acquisitions essential?

INTRODUCTION: The NMDA receptor radiotracer [18 F]GE-179 has been used with 90-min scans and arterial plasma input functions. We explored whether (1) arterial blood sampling is avoidable and (2) shorter scans are feasible.

METHODS: For 20 existing [18 F]GE-179 datasets, we generated (1) standardised uptake values (SUVs) over eight intervals; (2) volume of distribution (VT ) images using population-based input functions (PBIFs), scaled using one parent plasma sample; and (3) VT images using three shortened datasets, using the original parent plasma input functions (ppIFs).

RESULTS: Correlations with the original ppIF-derived 90-min VT s increased for later interval SUVs (maximal ρ = 0.78; 80-90 min). They were strong for PBIF-derived VT s (ρ = 0.90), but between-subject coefficient of variation increased. Correlations were very strong for the 60/70/80-min original ppIF-derived VT s (ρ = 0.97-1.00), which suffered regionally variant negative bias.

CONCLUSIONS: Where arterial blood sampling is available, reduction of scan duration to 60 min is feasible, but with negative bias. The performance of SUVs was more consistent across participants than PBIF-derived VT s.