Abstract: The use of a selective chemical and bioorthogonal reaction providing a covalent ligation such as the Staudinger ligation, in targeted molecular imaging and therapy is presented, more specifically with interesting applications for pre-targeted imaging or therapy. Current pre-targeted imaging is hampered by the fact that it relies solely on natural/biological targeting constructs (i.e. biotin/streptavidin). Size considerations and limitations associated with their endogenous nature severely limit the number of applications. The present invention describes how the use of an abiotic, bio-orthogonal reaction which forms a stable adduct under physiological conditions, by way of a small or undetectable bond, can overcome these limitations.

Abstract: FDG alternatives are provided. They consist of a two component system comprising on the one hand a building block such as glucose linked to an azide, alkyne or phosphine and on the other hand a detectable label linked to an azide, alkyne or phosphine which is the counterpart of the group linked to glucose in a Staudinger ligation reaction or a [3+2] cycloaddition reaction. It is preferred that the glucose is linked to an azide group and the detectable label is linked to a phosphine or cycloalkyne group. The detectable label is preferably a PET radionuclide label such as 18F.