Heteroatom Chemistry

illions of patients undergo PET (positron emission tomography) imaging every year, but there is a critical unmet need for new PET imaging probes capable of diagnosing and monitor-ing a multitude of diseases. One of the most versatile radionuclides for PET imaging is 18F, but rapid chemical synthesis of any probe based on 18F is essential because its physical half-life is only 110 min. Huiban et al. ( 1) recently reported an improved method for labeling trifl uoromethylarenes (Ar-CF3) with 18F that could greatly facili-tate the development and adoption of new PET probes and allow the site of action of existing drugs to be identifi ed. The only PET probe that has achieved widespread clinical application in the United States thus far is 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG; see the fi gure, panels A and B), which images cancer metabolism by pinpointing areas of high glucose usage ( 2, 3). Because cancer cells generally burn extra glucose as fuel, FDG-PET provides clini-cians with a diagram of cancer cell activity within the body. This method is now the stan-dard of care in oncology for diagnosis, stag-ing, and monitoring therapy. With the recent development of scanners that combine PET with computed tomography (CT), clinicians can now compare three-dimensional ana-tomical CT images with biochemical maps of fuel consumption in cancer tissue. For the past two decades, FDG has been the only 18F drug approved by the U.S. Food and Drug Administration (FDA) for PET imaging. Because PET-CT scans can reveal vital information about the anatomical structure within the body and its regional glucose con-sumption during the same examination, this method has the potential for understanding many other pathophysiological processes. In 2012, the FDA approved a second PET drug, Amyvid (fl orbetapir f18) (see the fi gure, pan-els A and C) ( 4), for detecting β-amyloid plaques, clumps of proteins that form around neurons in the brain and contribute to the development of Alzheimer’s disease (AD). Amyvid is now being used for patient selec