TSPO and amyloidosis: Given this background, the aims of the present cross-sectional multitracer study were: (1) to study the age-dependent changes in sTREM2 levels and μPET signals for the second generation TSPO tracer [18F]-GE180 together with that of the Aβ tracer [18F]-florbetaben in PS2APP and WT mice; (2) to evaluate the association of sTREM2 levels in the brain with the μPET signals and Aβ levels; and (3) to define the spatial and temporal relationships of TSPO activity and amyloidosis during aging of these mice.