99mTc-741F8-1 sFv

**99mTc-741F8-1 sFv** is a recombinant single-chain variable fragment (sFv) antibody, genetically engineered to include a terminal Gly4Cys peptide chelate that enables specific and efficient coordination of technetium-99m (99mTc), a gamma-emitting radioisotope[1]. This fusion protein targets the c-erbB-2 (HER2/neu) tumor-associated antigen, which is overexpressed in many breast and ovarian cancers[1][3]. After radiolabeling with 99mTc, the molecule enables tumor imaging via gamma camera/SPECT following intravenous administration. Its mechanism relies on highly selective binding to HER2-positive tumor cells, with rapid renal clearance and minimal non-target tissue retention, making it suitable for diagnostic tumor localization and potentially radioimmunotherapy[1]. It was developed collaboratively by academic and institutional researchers, with preclinical results showing strong tumor targeting and retention in xenograft models[1].