Gastric Emptying Solid and Liquid

1. Gastric Emptying Solid and Liquid By: Abby Cox NMT 1713 July 31,2007

2. Overview • What is Gastric emptying • Radiopharmaceutical and Dose • Localization & QC • Administration • Indications • Contraindicatons • Patient Preparation • Eqiupment • Procedure with solid • Procedure with liquid • Results (Normal and Abnormal) • Processing • Artifacts

3. Conclusion • Gastric Emptying is a procedure that measures how much food or liquid is moving out of the stomach at a certain time. • The procedure is done with a solid meal, liquid, or both together.

5. Gastric Emptying • Gastric emptying is a procedure that uses a radioactive material inserted in either a solid meal or liquid that measures the speed that the food or liquid is digested (emptied) through the stomach and enters into the small intestine. • Gastric emptying study is performed for patients who have symptoms of slow, or in rare cases rapid stomach emptying.

6. Radiopharmaceutical • Solid: 99mTc-Sulfur Colloid (SC)*, 99mTC-albumin colloid, In-111*, and Microlite (temporarily off the market) • Liquid: 99mTC-Diethylenetriaminepentaacetic acid (DTPA)*, and In-111* • Dose Range: -Solid: 5 mCi 99mTC SC, 2 eggs, 2 toast bread, & 8 oz OJ -Liquid: 500uCi 99mTC DTPA 125uCi In-111, DTPA Water, OJ, kool-aid * = Most common used

7. Localization & QC • Localization: Compartmental; moves along with food through gastrointestinal tract • QC: Chromatography: SC, > 90%; particle size < 1um; Micorlite, >92% tagging. Use either within 6 hours. DTPA, > 90%; use within 1 hour. • Administration: Radiotracer usually mixed with 1 or 2 whole eggs or egg whites for solid study. Radiotracer mixed into 120 mL of water or other for liquid and ingested orally

8. Indications • Evaluation of: -Mechanical obstruction -Anatomic obstruction (pyloric, postsurgical,postradiotherapy) -Altered function (gastroparesis, scleroderma, amyloidosis, or anorexia nervosa -Suspected tumors or surgery -Nausea, vomiting, and early satiety -Weight loss -Gastric therapy (Reglan) Determination of Delayed gastric emptying with quantitation of gastric emptying rate.

9. Contraindications • Allergy to eggs; in this case you would use oatmeal, baby food, sweet potatoes, or chicken or beef liver.

10. Patient Preparation • Identify the patient • Verify Doctor’s order, and explain procedure • Ensure the 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 • Premenopausal women should be studied on day 1-10 of the menstrual cycle to avoid hormonal variation effects, if possible

11. Equipment • Camera: Large or Small field of view • Collimator: Low energy, all purpose, or low energy, high resolution or medium energy collimator if In-111 is used.

12. Procedure with Solid • Baseline Solid Study: -Prepare one or two eggs and mix in radiotracer -Stir and Scramble -Or prepare choice of gastronomic vehicle with radiotracer -Administer to patient PO with 30-120 mL of water. Encourage patient to eat quickly. • Place Patient supine and start acquisition as quickly as possible after ingesting food. • Position camera anterior or LAO. • Instruct patient to remain motionless during imaging. • Static images: 60-120sec per frame every 5 minutes up to 30 minutes, and then every 15 minutes thereafter. • Dynamic images: 60sec/fr for 60-90min • Once complete draw a ROI around stomach and counts are generated • 64 x 64 or 128 x 128 matrix

13. Baseline Liquid Study • Add 500uCi of 99mTc-DTPA to 120mL of water or orange juice • Administer to patient PO. Encourage patient to drink quickly • Image same as solid study, although only imaged for 1.5 hours. • 64 x 64 or 128 x 128 matrix

14. Solid and Liquid Procedure • 500 uCi 99mTC SC injected into 2 raw eggs and then cooked. • 125uCi of In-111 in tap water or orange juice • Patient eats egg sandwich and drinks the tap water or orange juice • Imaging begins with camera peaked at two energy settings In-111(247 keV with a 20% window) and 99mTc (140 keV with a 20% window) • 64 x 64 or 128 x 128 matrix • 60 second images taken every 15 mins for 2 hours. • ROI is drawn around stomach and counts are generated for each image

15. Results (Normal & Abnormal) • Normal: Liquid: 50% emptied 10-45 minutes or 80% in 1 hour Solids: 50% movement out of stomach within a 32 – 120 minutes with a mean of 90 minutes. Terminate study before 60 min if gastric emptying becomes > 95% Abnormal: Very little or no movement from stomach after 60 minutes. Rapid emptying may occur in cases of “dumping syndrome”

16. Processing • Calculate percent emptying by follow methods: • Computer program • Generate regions of interest (ROI) around stomach • Manual: Use counts taken in ROI, correct counts by following decay factors • Divide gastric counts by decay factor to obtain corrected counts • This is performed on each frame, then plotted on a semilogarithmic graph, and compared with a normal curve.

17. Artifacts • Burn eggs; nonuniform mixing of radiotracer and eggs • Too little or to much food or water • Patient allergies or intolerance to eggs or to food • Patient unable to eat or may vomit or aspirate food and dose • Belt buckles or buttons • Camera or patient position changes

18. Questions • 1.) What are the 3 methods of performing Gastric Emptying study? • 2.) What is the common radiopharmaceuticals used with Gastric Emptying study? • 3.)What is the dose for each? • 4.) Name 1 indication and 1 contraindication of Gastric Emptying. • 5.) What is the acquisition for each?

19. Answers • 1.) Solid, Liquid, or solid and liquid • 2.) 99mTc-SC, 99mTc-DTPA, and In-111 • 3.) 5 mCi 99mTc-SC, 500uCi 99mTC DTPA, 125uCi In-111, DTPA • 4.) Refer to slides 6 and 7 • 5.) Refer to slides 10, 11, and 12

20. Reference • Nuclear Medicine Technology Procedures and Quick References by Pete Shackett • Society of Nuclear Medicine Procedure Guideline for Gastric Emptying and Motility