Definition

A radioconjugate composed of the imaging probe albumin-binding domain (ABD)-derived affinity protein (ADAPT) 6, which contains the ABD of streptococcal protein G as a stable protein scaffold, targeting human epidermal growth factor receptor 2 (HER2; EGFR2; ErbB2), and labeled with technetium Tc 99m, with potential imaging activity using single photon emission computed tomography (SPECT)/computed tomography (CT). Upon administration, the anti-HER2 binding moiety of technetium Tc 99m ADAPT6 targets and binds to HER2-expressing tumor cells. Upon SPECT/CT imaging, HER2-expressing tumor cells can be detected. HER2, a receptor tyrosine kinase, is mutated in many tumor cell types and plays a key role in tumor cell proliferation and tumor vascularization.