There is a need for new methods of C radiosynthesis because current methods are largely limited to methylation. The Vasdev lab has co-developed new techniques of CO fixation that are suitable for human use with diverse precursors synthesized by labeling at the carbonyl group (rather than the common methyl group). This methodology can label C-carbamates for imaging the enzyme FAAH ([C]CURB) or C-oxazolidinones for imaging MAO-B (C-SL25.1188), both of which they have translated for human use. They have also synthesized C-ureas and a C-carboxylic acid (C-Bexarotene).