FIG. 4.

Fluorescent images of HEL xenograft-bearing athymic mice treated with either conventional RIT or PRIT. Mice were injected with either (A) 1.4 nmol anti-human CD45 antibody directly labeled with fluorophore or (B) pretargeted anti-human CD45 antibody–streptavidin conjugate (1.4 nmol) followed 22 hours later by a clearing agent and then by 100 mg R-phycoerythrin-biotin. Images are shown at same camera intensity settings. Images of mice are shown at 12 hours after injection of the fluorophore. Arrows indicate fluorophore in tumor (T) and blood pool (B). (C) Tumor–to–whole-body fluorescence ratios at 8 hours after injection in conventional RIT and PRIT mice. Reproduced with permission from Pagel et al.¹¹² PRIT, pretargeted radioimmunotherapy.