FIGURE 5. Representative -images of mice without (A) and with (B) C225 pretreatment 6 and 24 h after radiotracer injection. Mice with A431 tumors were injected with 1:30 ¹¹¹In-DTPA-PEG-C225 alone or 20 h after injection of unlabeled C225 at dose of 1 mg per mouse. Pairs of mice used in imaging study were matched for size of tumors. Tumors (arrowheads) in mouse injected with only 1:30 ¹¹¹In-DTPA-PEG-C225 are clearly visualized (A), whereas tumors (arrows) in mouse pretreated with C225 are hardly seen (B). Anterior views of mouse placed prone on camera’s pinhole collimator, with head pointing to top.