Scintigraphic Evaluation of Gastrointestinal Transit

To evaluate gastrointestinal transit parameters, an adaption of our established scintigraphic method was used [14 (link), 15 (link), 28 (link)]. Briefly, 0.1mCi ¹¹¹InCl₃ was mixed with a slurry of 5 mg of activated charcoal. The mixture was allowed to evaporate to dryness, after which the radiolabeled charcoal was packed into a gelatin capsule. This capsule was coated with one layer of methacrylate (Eudragit L, The Dow Chemical Company) which dissolves in a pH-sensitive manner upon reaching the alkaline terminal ileum, thus allowing radiolabel to be transferred to the colon for quantitation of colon transit. The ¹¹¹In containing capsule was administered following an overnight fast. After this capsule had emptied from the stomach, subjects ingested a ^99mTc-labeled meal. Estimation of colonic filling with ^99mTc at 6 hours (CF6h) served as a surrogate for small bowel transit. Subjects ingested standardized meals for lunch and dinner, 4 and 8 hours after the radiolabeled breakfast, respectively. Using a gamma camera, abdominal images with anterior and posterior cameras of 2 minutes duration were acquired immediately following ingestion of the radiolabeled meal and at specified time points during the subsequent 48 hours period.