Gastric emptying differences between eggs and oatmeal, with focus on preparation of mixing and not mixing Tc99m-sulfur colloid.

Objectives Although gastric emptying diagnostic imaging scan is used frequently, there is a lack of standardization with regard to the meal preparation and how the technologist administers the Tc-99m sulfur colloid into the meal itself. If the radioactive tracer was introduced into the center of the uncooked food and left unmixed or introduced then mixed, it is conceivable the final results might be affected adversely as a result of the variation in the protocol.

Methods A four image procedure was conducted by comparing and drawing ROI’s around each image with a total particle count. Two oatmeal and two egg meals were prepared. One set with mixed sulfur colloid and one set without mixing. A total of 460uCi of Tc-99m sulfur colloid were divided up between the four images. The imaging was conducted on a VXHR collimator with a 64x64 matrix. A one minute static image was taken posteriorly and anteriorly of each prepared meal.

Results Even after mixing the radioactive tracer and eggs together for five seconds there remained a count concentration in the middle of the bowl although it was significantly less than the count concentration that remained with no mixing. The images of the oatmeal indicate that the counts were evenly distributed after mixing the radioactive tracer and oatmeal together. Without mixing, the counts still indicated a significant passive distribution of the sulfur colloid. Although the radioactive tracer did disperse more effectively than it did it in the eggs, oatmeal appeared to have no binding property and proved to be a poor choice for a gastric emptying scan

Conclusions Variations on gastric emptying studies are expansive and numerous. Modifications of the protocols can be put into place to reduce these variations. Taking into account the results from this particular study, a modification that could be made during meal preparation is mixing the radioactive tracer for a minimum of five seconds prior to cooking. The consumption of eggs over oatmeal is the better choice for a gastric emptying study due to the eggs binding ability from the protein.