Autoradiography images and fluorescent immunostaining. Autoradiography images of [18F]-7B binding in an AD frontal cortex section following incubation with [18F]-7B (10 nM) alone (A) or in the presence of 7A (2.5 μM) (C). Fluorescent immunostaining of sections (A) and (C) with an anti-Aβ antibody is shown in (B) and (D), respectively. The autoradiography images demonstrate laminar distribution of [18F]-7B binding in cortex (bracket and arrows), which correlates with the distribution of Aβ plaques shown by fluorescent immunostaining, and binding of [18F]-7B is inhibited by excess cold ligand (C). The higher nonspecific binding in the lower left region (A) is due to folding of the tissue section.