A single scan technique for estimating acid output.

A single scan technique using 99mTc has been developed for the measurement of gastric acid output. After an overnight fast, pentagastrin (6 microgram/kg S.C.) was given 15 min before 99mTc (1 mCi i.v.), and a scan of the abdomen was performed 15 min later using a double-headed scanner. Accumulation of isotope within the stomach was then calculated from the scan and expressed as a percentage of the injected dose. Pentagastrin-stimulated intragastric activity correlated with acid output measured conventionally on a separate occasion (r = 0.87, P less than 0.0001). The test is rapidly performed with minimal inconvenience and discomfort to the patient, and the dose of irradiation used is small. The advantages of the method compared with intubation and gastric aspiration are discussed.