Clinicians would like to have complexes that can be used for both diagnostic positron emission tomography (PET) imaging and radiotherapy. Fluorine-18 is the isotope most frequently used for PET imaging, but it can’t be used as a therapy. Eszter Boros and coworkers at Stony Brook University have made a complex that has both 18F and scandium (Angew. Chem., Int. Ed. 2021, DOI: 10.1002/anie.202114203). Fluorine binds more strongly to scandium than to aluminum, which has been used previously to form PET agents. The researchers formed the agent by incubating a macrocyclic chelator with a Sc–18F species for 30 min. “We have actually not optimized the labeling time,” Boros writes in an email. “Any time we spend doing chemistry, we are not doing imaging, so we need to improve upon this.” The preparation step is faster than that for many other 18F-labeled compounds because no additional synthetic steps are required. By replacing the stable 45Sc isotope with the radioactive 47Sc isotope, the complex becomes a potential radiotherapy. The researchers tested the compound in mice with tumors expressing the prostate-specific membrane antigen (PSMA), and conjugated the complex to a peptide that targets PSMA. The imaging agent accumulated in the tumor and kidneys, indicating renal clearance.