Figure 5.

Representation of the biFuntional approach. By this approach, an RP can be described as mainly composed of two essential parts: the targeting vector, i.e., the molecule or macromolecule that drives the radiometal to the pertinent molecular target, and the chelating system (also known as the BiFuntional Chelator, (BFC) designed to promptly and robustly bind the metal radionuclide, preventing it’s in vivo leakage, and to carry another reactive group able to form a strong covalent bond with the targeting vector, thus yielding a kinetically and thermodynamically stable construct. These two parts are directly bound or are held together by an appropriate linker or pharmacokinetic modifier (PKM). The final compound (bioconjugate complex) is then obtained through the appropriate labeling procedure, which depends on the specific radiometal.