Radiolabelling and evaluation of novel haloethylsulfoxides as PET imaging agents for tumor hypoxia

Abstract

The significance of imaging hypoxia with the PET ligand [18F]FMISO has been demonstrated in a variety of cancers. However, the slow kinetics of [18F]FMISO require a 2-h delay between tracer administration and patient scanning. Labelled chloroethyl sulfoxides have shown faster kinetics and higher contrast than [18F]FMISO in a rat model of ischemic stroke. However, these nitrogen mustard analogues are unsuitable for routine production and use in humans. Here we report on the synthesis and in vitro and in vivo evaluation of two novel sulfoxides which we synthesised from a single precursor molecule via either 2-[18F]fluoroethyl azide click chemistry or conventional nucleophilic displacement of a..