A Cheesy Alternative: Pediatric Gastric Emptying

Introduction: Gastric emptying exams are a common occurrence in most nuclear medicine departments that rely on radiolabeling a food or liquid in order to study how the body digests food and water. Historically, gastric emptying exams have been done using 120g of Tc99m Sulfur Colloid (SC) labeled eggs, two slices of white bread, 30g of jelly, and 120ml water. Due to the most common indication being nausea and vomiting, the study is not always successful, and pediatric patients pose additional challenges when completing the exam using the standard meal of eggs. The purpose of this study is to identify an alternative meal that may be more pleasing to pediatric patients.

Methods: A literature review was done to identify alternative meals used on gastric emptying studies in the pediatric population and the clinical use of these alternative meals. In addition, a Qualtrics survey was sent to nuclear medicine technologists (NMT) in the St. Louis area who regularly perform gastric emptying studies on pediatric patients. The survey questions included but not limited to: patients complaining about the standard egg meal, patients refusal due to the egg meal, NMTs willingness to use a meal alternative, and any concerns using mac and cheese as an alternative to eggs if proved effective.

Results: Literature showed that radiolabeling foods with Tc99m SC yielded a higher efficiency when the radiopharmaceutical is cooked into the substance rather than just being mixed in. With this in mind, using cheese as an alternative to eggs can be achieved by taking slices of cheddar cheese and melting them with the Tc99m SC. Drubach’s study compared the activity bound to different meals for the purpose of a gastric emptying scan and found that at 1 hour, 0.1mCi of Tc99m SC was bound to 98%±2 in egg whites and 96%±1 in cheese. At 4 hours the activity bound in egg whites was 98%±1 and 96±1 in cheese. Furthermore, Wichlacz’s article discussed mixing Tc99m labeled cheese with noodles to make mac and cheese. His study showed a T-test p-value of .0005 when comparing the use of eggs versus cheese in healthy patients and found that both fell within the established SNMMI guidelines for gastric emptying values, concluding that using cheese is a viable option. Based on surveys that were sent to children's hospitals/clinics, gastric emptying exams are ordered on pediatrics about 4-5 times a month and are reported to oftentimes be unsuccessful. Many NMTs expressed that the standard egg meal is the main cause of canceled exams and when asked if their patients would choose mac and cheese or eggs, all answered in favor of the mac and cheese with some even adding that the new alternative might lead to higher success rates. The main concern from a technologists standpoint was mainly focused on the radiopharmacies preparation, and how that process would compare as a whole to current standard procedure.

Conclusions: Binding Tc99m to cheese has been proven to be just as effective as eggs, and requires simple preparation that puts an ease on technologists and pharmacists. Although mac and cheese is a viable option for gastric emptying studies, it has not yet been considered or adopted clinically despite the possibility of raising success and satisfaction rates in pediatric departments. Future research should focus on proving its ease of use and developing plans/logistics of transitioning over to using mac and cheese.