Single step 18F-labeling of dimeric cycloRGD for functional PET imaging of tumors in mice

Advances in Knowledge and Implications for patient Care: Despite many antecedent examples of labeled RGD tracers, this work is the first to show direct aqueous labeling of bisRGD with an 18F-ArBF3−. Labeling occurs in near record rapidity (45 min) at useful effective specific activities and competitive yields for high contrast tumor specific images. As bisRGD has been imaged in humans with several prosthetics, this work suggests potential clinical applications of tracers appended with an 18F-ArBF3−. More generally, the ability to label a molecularly complex tracer suggests that this method could be useful to label many other peptides. Furthermore, these results portend the development of kits that use only microgram quantities of lyophilized precursor for on demand labeling. The ability to perform one-step aqueous labeling in under an hour to provide tracers with high T:NT ratios has important implications for developing radiotracers for use in fundamental research and in preclinical tracer studies.