PETand Macro- and Microautoradiographic Studies Combinedwith Immunohistochemistry for Monitoring Rat Intestinal Ulceration and Healing Processes

18F-FDG PET is used mainly in clinical settings for imaging focal cancer sites, but the usefulness of the modality in imaging gastrointestinal ulcers has not been established. We investi-gated whether PET can be used for noninvasive monitoring of indomethacin-induced small-intestine ulceration. Methods: Intestinal ulcers were induced in rats by subcutaneous adminis-tration of indomethacin. An 18F-FDGPET scanwas obtained at 1, 2, and 7 d after indomethacin administration. 18F-FDG uptake in the small intestine was quantified by g-counting, andmacro- and microautoradiographic studies were performed to determine the site of 18F-FDG uptake in tissue and at the cellular level.Results: Ulcers observed in the intestine (mainly in the ileum) 1–4 d after indomethacin administration were most severe at 1 d after ad-ministration and were almost healed at day 7. The PET study showed increased 18F-FDG uptake in the intestine correlatin