Definition

A radioimmunoconjugate composed of panitumumab, a human immunoglobulin G2 (IgG2) monoclonal antibody directed against the epidermal growth factor receptor (EGFR; HER1; ErbB1), labeled with the radioisotope indium In 111, with potential use as an imaging agent upon single photon emission computed tomography/computed tomography (SPECT/CT). Upon administration of Indium In 111 panitumumab, the antibody moiety targets and binds to the extracellular domain of EGFR on tumor cells. Upon SPECT/CT imaging, EGFR-expressing tumor cells can be visualized and assessed. EGFR, a receptor tyrosine kinase overexpressed on the cell surfaces of many tumor cell types, plays a key role in tumor cell proliferation.