EFFECTS OF MEAL SIZE AND CORRECTION TECHNIQUE ON GASTRIC-EMPTYING TIME - STUDIES WITH 2 TRACERS AND OPPOSED DETECTORS

Abstract

Geometric-mean correction of gastric radioactivity can be used to correct for the distribution, depth and attenuation of the radionuclide. Anterior image counts were compared with the geometric mean of anterior and posterior counts, using a computer-assisted gamma camera. Phantom and human studies using 99mTc and 111In were used to evaluate the difference between anterior-only and geometric-mean data. The effect of meal size on gastric emptying was studied using 99mTc and 11In simultaneously as solid-phase and liquid-phase markers. Differences between the anterior data and AP-PA data corrected by geometric mean were compared in 10 healthy male subjects. The average half-emptying times for solid food, with 1692, 900 and 300 g meals, were 277, 146 and 77 min, respectively. Average half-emptying times for liquid were 178, 81 and 38 min for the same meals.