Biodistribution and radiation dosimetry of a positron emission tomographic ligand, 18F-SP203, to image metabotropic glutamate subtype 5 receptors in humans

Purpose A new PET ligand, 3-fluoro-5-(2-(2-18F-(fluoromethyl)-thiazol-4-yl)ethynyl)benzonitrile (18F-SP203), is a positron emission tomographic radioligand selective for metabotropic glutamate subtype 5 receptors. The purposes of this study were to estimate the radiation-absorbed doses of 18F-SP203 in humans and to determine from the distribution of radioactivity in bone structures with various proportions of bone and red marrow whether 18F-SP203 undergoes defluorination.