Chelates for Biomedicinal Use

Abstract

Magnetic resonance imaging (MRI) and positron emission tomography (PET) have gained a great importance in the last thirty years in medicinal diagnostics as imaging techniques with a superior spatial resolution and contrast. MRI has assumed a critical role in medicinal diagnosis and applications of contrast agents (CAs), mostly based on Gd(III) complexes. For this purpose, specific CAs have been developed, changing relaxivity after cleavage of some bonds sensitive to the presence of specific ions or metabolites. For PET applications, a new isotope ⁶⁸Ga(III) has been proposed. In view of utilization of toxic ions, the crucial condition for their applications in vivo is their complexation in stable species. In this review, the ligand types and structures of their complexes as well as their physicochemical parameters are discussed.