[18F]SiFA‐isothiocyanate: A New Highly Effective Radioactive Labeling Agent for Lysine‐Containing Proteins

Abstract

A highly efficient ¹⁸F‐labeling synthon for universal protein labeling is reported. Diverse ¹⁸F‐labeled proteins of 66–144 kDa were prepared with [¹⁸F]SiFA‐isothiocyanate synthesized by an isotopic ¹⁹F for ¹⁸F exchange at the silicon atom. Overall preparative radiochemical yields were 20–40 % after 40–50 min. No bone uptake of ¹⁸F radioactivity was detected until 90 min post‐injection of ¹⁸F‐SiFA‐RSA; this demonstrates the metabolic stability of the [¹⁸F]SiFA moiety.