The Volumetric.Measurement of Gastric Emptying and Gastric Secretion by a Radioisotope Method

Most methods of measurement of gastric emptying rely on the serial estimation of intra-gastric volume and do not separately account for the volume of fluid which has been add-ed to the meal by gastric secretion, duodenal reflux, or swallowed saliva. The volume emp-tied is therefore underestimated. A method of measuring gastric emptying using [125I]RIHSA and the Vol~metron is presented. The volume of fluid added to the meal is taken into consideration i this method, giving a more accurate reflection of gastric emp-tying. Using this method in the dog, emptying was found to be linear rather than exponen-tial. We have previously reported a method of measure-ment of intragastric volume using the Volrmetron and [t2~I]RIHSA (radioiodinated human serum albu-min) (1). The Volrmetron is an apparatus, using an isotope dilutional technique, normally used for the measurement of blood volumes. The apparatus measures the radioactivity of a dose of [12~I]RIHSA, which is then injected into a volume of fluid to be measured. Specimens (2 ml) of the volume of fluid are taken before (premix) and after (postmix) the in-jection of [12~I]RIHSA and have their radioactivity measured in the Vol6metron. With the information of the change of isotope concentration afforded by the injection of a known amount of [lzSI]RIHSA, the apparatus i able to automatically compute and dis-play this volume. Repeated estimations of the sam