The Use of the Macrocyclic Chelator DOTA in Radiochemical Separations

Radiometals play an important role in the diagnosis of physiological processes in vivo by means of imaging technologies, but also increasingly contribute to the treatment of diseases. The by far dominant way to apply the advantages of nuclear transformations of radiometals is the use of radiometal-ligand complexes. In this context, it turns out that DOTA (and its derivatives) currently is the most potent chelator. This article reviews the physico-chemical properties of DOTA and its [*M(DOTA)](-) complexes, which made the DOTA moiety the dominant chelator for theranostics in radiopharmaceutical chemistry and nuclear medicine. Interestingly, and beyond nuclear medicine applications, the physico-chemical properties of [*M(DOTA)] complexes open access to unique radiochemical separation strategies, which for decades appeared to be impossible not only within conventional chemistry, but also within modern radiochemistry. We will discuss three groups of such separations: i) the radiochemical separation of two chemically very similar elements such as two neighbor lanthanides, ii) the radiochemical separation of two isotopes of the same element, and even iii) the radiochemical separation of two nuclear levels of one and the same isotope.