A gastric emptying study is a procedure that using radioactive isotope that measures the speed with which food empties from the stomach and enters the small intestine. Gastric emptying studies are used for testing patients who are having symptoms that may be due to slow and, less commonly, rapid emptying of the stomach. The symptoms of slow emptying are primarily nausea, vomiting, and abdominal fullness after eating. The symptoms of rapid emptying are diarrhea, weakness or light-headedness after eating.

Radionuclide 99mTc t1/2: 6 hours

111In t1/2: 2.8 d, Energies: 173, 247 keVType: EC, γ, accelerator

Radiopharmaceutical Solid: 99mTc-SC (sulfur colloid), 99mTc-albumin

colloidLiquid: 99mTc-DTPA

(diethylenetriaminepentaacetic acid), 111In-DTPA (diethylene triamine pentaacetic acid)

Adult Dose Range 99mTc: 100 µCi to 1 mCi (3.7–37 MBq) 111In: 125 uCi (4.6 MBq)Method of Administration Solid: Radiotracer usually mixed with 1 or 2 whole

eggs or egg whites (or oatmeal, beef stew, liver, some use a whole sandwich) with or without toast (type of meal and amounts vary).

Liquid: Radiotracer mixed into 120 cc water or other (orange juice, milk) for liquid and ingested oral ly. 111In-DTPA in 300 mL of water for simultaneous study. Pediatrics: “milk scan” (mix in milk or formula).

Determination of delayed gastric emptying with quantitation of gastric emptying rate.

Evaluation of mechanical obstruction.Evaluation of anatomic obstruction (pyloric,

postsurgical, postradiotherapy).E va l ua t i on fo r a l t e r e d func t i on , e . g . ,

gastroparesis (delayed gastric emptying) (diabet ic and idiopathic) , scleroderma, amyloidosis, or anorexia nervosa.

Evaluation of suspected tumors or surgery.

Evaluation of nausea, vomiting, early satiety, u p p e r a b d o m i n a l d i s c o m f o r t , b l o a t i n g , gastroesophageal reflux and/or chronic aspiration.

Evaluation of weight loss.Evaluation of gastric therapy.

Allergy to eggs; use oatmeal, baby food, sweet potatoes, chicken or beef livers.

Hypoglycemic patient.

Identify the patient. Verify doctor's order. Explain the procedure.

Ensure that diabetics receive orange juice 2 hours before test if necessary.

Ensure patient to be NPO 4–12 hours before examination.

Physician to discontinue sedatives 12 hours before examination.

CameraLarge or small field of viewCollimatorLow energy, all purpose, or low energy, high

resolutionComputer Set-up Statics Preset for 60–120 seconds or 50,000 countsDynamic Preset for 60 sec/image, 60–90 minutes

Baseline Solid Study Prepare one or two eggs and mix in radiotracer. prepare choice of gastronomic vehicle with

radiotracer.Administer to patient PO followed by 30–120 mL

of water. Encourage patient to eat quickly (within 10 minutes).

Place patient in supine position. Acquisition should be started as quickly as possible after ingestion of food.

Position camera anterior or LAO. Instruct patient to remain motionless during

imaging.

Obtain static images every 5 minutes up to 30 minutes, then every 15 minutes thereafter, allowing patient to ambulate between images. If camera and/or patient moves between images, reposition patient for subsequent imaging by using a small marker at a specific point on the patient and circling the spot on the p-scope for ease of processing. Realign marker and circle, then remove marker for subsequent images.

Dynamic supine images: preset for 60–90 minutes. Patient remains motionless under camera.

Supine is good for checking esophageal reflux.

Position patient standing or sitting upright, one image facing camera. Optional: one image with back to camera.

Use patient realignment technique described above.Obtain immediate image(s), then every 10 minutes. Standing, sitting, then standing uses normal

movement and gravity to aid realism in study.

Add 500 µCi of 99mTc-DTPA to 120 mL of water or orange juice.

Administer to patient PO. Encourage patient to drink quickly.

Images same as solid study, although only imaged for 1.5 hours.

Peak camera for both 99mTc and 111In (247 keV), 20% windows, LEHR or LEAP collimator.

Patient fasting for at least 8 hours. Solid portion is 500 uCi 99mTc-sulfur colloid in eggs or

meal usually given. Liquid portion is 125 uCi 111In-DTPA in 300 mLs of

water. Patient is instructed to eat eggs within 5 minutes, and

then wash down with liquid portion of meal. Begin imaging immediately using protocol of choice.

If computer has correct software, both can be imaged at the same time.

Imaging should run 60 to 120 minutes.

Liquid: t 1/2 (50%) at 10-15 min or 80% in 1 hour.

Solid : t 1/2 (50%) movement out of stomach within a lower limit of 32 min to an upper limit of 120 min with an adult mean of 90 min. other suggest 63% by 1 min.

Terminate study before 60 min if gastric empting became > 95%.