Imaging of gastrointestinal absorption and biodistribution of an orally administered probe using positron emission tomography in humans

Clin Pharmacol Ther. 2012 Apr;91(4):653-9. doi: 10.1038/clpt.2011.267. Epub 2012 Feb 29.


The purpose of this study was to establish a method for imaging the process of gastrointestinal (GI) absorption and subsequent biodistribution in the human body after oral drug administration, using positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxy-D-glucose ([(18)F]FDG). First, we developed a method to deliver the radiotracer safely into the stomach using soft gelatin capsules to avoid any significant exposure to the pharyngoesophageal region. Second, we performed pharmacokinetic (PK) analyses on time-radioactivity profiles in GI tissues and blood to calculate the gastric emptying and intestinal elimination rate constants and to estimate the fluid volume in the lumen of the small intestine from PET image analysis. This is the first study involving oral administration of a PET probe in humans, and the results demonstrate the high potential of PET technology to investigate the GI absorption and PK profiles of drugs in humans.

Publication types

  • Comparative Study

MeSH terms

  • Administration, Oral
  • Adult
  • Atenolol / administration & dosage
  • Atenolol / metabolism
  • Fluorodeoxyglucose F18 / administration & dosage
  • Fluorodeoxyglucose F18 / metabolism*
  • Gastric Emptying / drug effects
  • Gastric Emptying / physiology*
  • Gastric Mucosa / metabolism*
  • Gastrointestinal Contents / chemistry
  • Gastrointestinal Contents / diagnostic imaging*
  • Humans
  • Intestinal Absorption / drug effects
  • Intestinal Absorption / physiology*
  • Male
  • Molecular Probes / administration & dosage
  • Molecular Probes / metabolism
  • Positron-Emission Tomography / methods*
  • Radiopharmaceuticals / administration & dosage
  • Radiopharmaceuticals / metabolism*
  • Stomach / diagnostic imaging*
  • Stomach / drug effects
  • Tissue Distribution / drug effects
  • Tissue Distribution / physiology
  • Young Adult


  • Molecular Probes
  • Radiopharmaceuticals
  • Fluorodeoxyglucose F18
  • Atenolol