F-labeled agents in tumor-bearing nude mice by small-animal PET. Coronal slices of three nude mice bearing small, subcutaneous LS174T tumor on each left flank after being injected with either (A) 18F-FDG, (B) Al18F-IMP449 pretargeted with anti-CEA x anti-HSG bsMAb, or (C) Al18F-IMP449 alone (not pretargeted with bsMAb). Biodistribution data expressed as percentage injected dose per gram (% ID/g) are given for tissues removed from animals at conclusion of the imaging session. Br, brain; BM, bone marrow; H, heart; K, kidney; T, tumor (reproduced with permission from the Journal of Nuclear Medicine; McBride et al. ).