Tagging Efficiency of 99m Tc-SC Radiolabeled Alternative Gastric Emptying Meals: A Quantitative Study

Objective The aim of this study was to know the tagging efficiencies of technetium-99m labeled sulfur colloid (99mTc-SC) with different meals. Materials and Methods Egg white sandwiches are the gold standard for gastric-emptying scan (GES); thus, an egg white omelet labeled with (99m) Tc-SC is taken as a standard meal. For evaluation, we included four meals, bread and butter, instant oatmeal, idli, and chapatti, and all meals were prepared by labeling them with (99m) Tc-SC. After preparation, food articles were chopped with the help of a metal fork and mixed in simulated gastric fluid. Four samples were taken simultaneously from each food article and analyzed for 1 to 4hours after agitation within the centrifuge. The samples were filtered and separated from the sediments and supernatants. We analyzed the activity in each sample before and after filtration. Results The mean values of labeling efficiency in per cent of various meals were obtained. There was no significant difference in labeling stability for egg whites, chapatti, and idli meals labeled with (99m) Tc-SC from 1 to 4hours as their p -value (p>0.05) was insignificant. Conclusion Radiolabeled chapatti and idli with (99m) Tc-SC show higher labeling stability, while oatmeal and bread and butter samples show relatively low stability. Thus, for GES, chapatti and idli labeled with (99m) Tc-SC can be used as alternatives to eggs for vegetarian people or for those allergic to eggs.