¹⁸F-FDG PET images of a 7-year-old child with a history of gastrointestinal stromal tumor, who underwent imaging because a liver lesion was suspected. The PET images show a physiologic accumulation of ¹⁸F-FDG within the thymus gland, a normal finding in children. Courtesy of Mohei M. Abouzied, MD, University at Buffalo, Buffalo, New York.