(a) Comparison of σ0 vs. σm as utilized in frame-independent vs. frame-dependent regularizations (13) and (11). To minimize dependence on early-uptake, highly-varying noise levels, only σm values for frames with t>1.5min were averaged to obtain σ0, (b) Plots of resulting image NSD versus frame number for QP-MAP reconstruction using: (i) standard non-regularized MLEM shown as reference, (ii) QP-MAP with frame-independent regularization (MAP (β0)), and (iii) QP-MAP with frame-dependent regularization (MAP (βm)).