Endocrine Neoplasia

18F-4FN represents a novel PET agent for imaging inflammation. Acute inflammatory signaling through the TLR axis recruits neutrophils and macrophages to inflammatory sites. Both cells activate the production of high energy reactive oxygen species/reactive nitrogen species (RONS), setting off a cascade that can be leveraged to detect the presence of these inflammatory cells by molecular imaging. 18F-4FN is efficiently oxidized by high energy RONS, leading to retention and accumulation in human neutrophil-like cells in vitro, and at the sites of acute inflammation in vivo. Like 18F-FDG, 18F-4FN clears rapidly through the kidney at 1 hr following i.v. injection