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

The NMDA receptor radiotracer [¹⁸F]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.

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

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

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 V_Ts.