NCIt definition : A radioimmunoconjugate comprised of the recombinant humanized monoclonal antibody
bevacizumab labeled with the radioisotope zirconium Zr 89 (Zr 89) with radioisotopic
activity and potential imaging use. The antibody moiety of zirconium Zr 89 bevacizumab
targets and binds to the extracellular domain of the vascular endothelial growth factor
receptor (VEGFR). Upon binding, the radioisotope moiety may be detected using positron
emission tomography (PET), allowing the imaging and quantification of VEGFR-expressing
tumor cells. VEGFR, a tyrosine kinase, is overexpressed on the cell surfaces of various
tumor cell types.;