To assess the consistency of the SPITFIRE™ estimator across tracers, we selected subjects with pairs of PET images with different tracers, but scanned no more than 3 months apart.

The figure shows scatter plots of the resolution estimation for each pair of tracers. Notice that, in each case, the correlation between tracers is slightly greater for the in-plane resolution as compared to the axial resolution, perhaps driven by the typically greater voxel size in the axial direction.