PET Tracers Based on Zirconium-89

Positron emission tomography (PET) imaging with radiolabeled monoclonal antibodies has always been a dynamic area in molecular imaging. With decay half-life (3.3 d) well matched to the circulation half-lives of antibodies (usually on the order of days), Zr-89 has been extensively studied over the last decade. This review article will give a brief overview on Zr-89 isotope production, the radiochemistry generally used for Zr-89-labeling, and the PET tracers that have been developed using Zr-89. To date, Zr-89-based PET imaging has been investigated for a wide variety of cancer-related targets, which include human epidermal growth factor receptor 2, epidermal growth factor receptor, prostate-specific membrane antigen, splice variant v6 of CD44, vascular endothelial growth factor, carbonic anhydrase IX, insulin-like growth factor 1 receptor, among others. With well-developed radiochemistry, commercial availability of chelating agents for Zr-89 labeling, increasingly widely available isotope supply, as well as successful proof-of-principle in pilot human studies, it is expected that PET imaging with Zr-89-based tracers will be a constantly evolving and highly vibrant field in the near future.