What is a nuclear medicine gastric emptying study?
- Either liquid or solid-phase gastric emptying studies can be performed. Liquid studies are typically conducted on infants.
- After the infant receives a mixture of 99m Tc-sulfur colloid with milk or formula at the normal feeding time, imaging is performed and an emptying half-time is calculated.
- In adults, a solid-phase emptying study usually is performed after an overnight fast and subsequent ingestion of 99m Tc-sulfur colloid–labeled scrambled eggs as part of a standard meal.
- Anterior and posterior imaging is obtained with either dynamic imaging in 90 minutes or static images at 0, 1, 2, and 4 hours. The percentage of emptying is calculated based on the geometric mean of the anterior and posterior counts.
- A consensus statement by the Society of Nuclear Medicine has recommended the use of a low-fat, egg-white meal, although this is not necessarily used at every clinic and normal values are institution dependent and will obviously vary with different meal compositions.
- Using a 285-calorie meal of scrambled eggs, bread, and jam, normal t1/2t1/2 gastric emptying time (time at which 50% of the gastric contents is emptied) is less than 135 minutes.
