The F(ab')2 fragment of monoclonal antibody Mel-14, reactive with human melanomas and gliomas, was labeled with 18F using two acylation agents, N-succinimidyl 8-[(4'-[18F]fluorobenzyl)amino]suberate (SFBS) and N-succinimidyl 4-[18F]fluorobenzoate (SFB). The immunoreactivity and affinity for Mel-14 F(ab')2 labeled using the two methods were similar. As a prelude to human clinical evaluation, PET imaging, tissue distribution and pharmacokinetic measurements were performed in two groups of normal foxhounds. Similar in vivo behavior was seen for Mel-14 F(ab')2 labeled using SFBS and SFB. Radiation dosimetry calculations suggest that a 10 mCi dose could be used for this F(ab')2 fragment labeled using either acylation agent.