Highlighting New Research Trends on Zirconium-89 Radiopharmaceuticals Beyond Antibodies.

Zirconium-89 (Zr) is a cyclotron-produced positron-emitting radioisotope with a half-life of 3.27 days, which makes delayed or longitudinal imaging possible. It is a superior isotope for tracking particles over several days at a high sensitivity, resolution, and specificity. Zr-monoclonal antibodies (Zr-mAb) have gained significant attention in the field of molecular imaging. However, the past decade has shown an avid increase in research concerning Zr-radiopharmaceuticals apart from Zr-mAb. In this article we highlight and discuss the status and challenges attributed to current preclinical and clinical investigations of Zr-radiopharmaceuticals developed beyond Zr-mAb, e.g., mAb-derived variants and macro-biomolecules, proteins, peptides, nanoparticles, and living cells.