EGFR and neoplasm: [203Pb]Pb-TCMC-panitumumab-F(ab')2, the F(ab')2 fragment of the anti-HER1 antibody, panitumumab, showed similar biodistribution and tumor uptake in immunocompromised LS-174T tumor xenograft mice compared to the full-length antibody, [203Pb]Pb-TCMC-panitumumab.