The health care provider will inject a radioactive chemical called a gamma emitting tracer into a vein. This material will collect primarily in the liver and then flow with bile into the gallbladder.
You lie face up on a table under a scanner called a gamma camera. The scanner detects the rays being emitted from the tracer. A computer displays images of where the tracer is found in the organs.
Images will be taken every 5 - 15 minutes. The entire test takes about 1 hour.
If, after a certain amount of time, the gallbladder can't be seen, the doctor may give you a small injection of morphine, which can help to move the radionuclide into the gallbladder. The morphine may cause you to feel tired after the exam.
Sometimes during this test, you will be given a medication to help the health care provider see how well your gallbladder squeezes.
How to prepare for the test
You need to eat something within a day of the test. However, you must stop eating or drinking 4 hours before the test starts.
How the test will feel
When the tracer is injected into the vein, there will be a sharp prick from the needle. After the injection, the puncture site may be sore. There is normally no pain during the scan.
Why the test is performed
This test is very good for detecting acute infection of the gallbladder or blockage of a bile duct. It is also helpful in determining whether there is rejection of a transplanted liver.
It can also be used to detect long-term gallbladder problems and to see how well the gallbladder squeezes (contracts).
What abnormal results mean
Abnormal anatomy of the bile system (biliary anomalies)
There is a small risk to pregnant or nursing mothers, because the fetus or small child has a greater sensitivity to radioactive chemicals. Unless it is absolutely necessary, the scan will be delayed.
The amount of radiation is small (less than that of a conventional x-ray) and is virtually gone from the body within 1 or 2 days. With an increased number of scans, there is some radiation risk.
Because this test is usually not performed unless there is acute pain, suspected gallbladder disease, or gallstones, many patients require urgent attention after the results of the test are known. Sometimes this test is combined with other imaging (such as CT or ultrasound). After the gallbladder scan the patient may be prepared for surgery, if it is necessary.
Afdahl NH. Diseases of the gall bladder and bile ducts. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier;2007:chap 159.
Wang DQH, Afdahl NH. Gallstone disease. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 9th ed. Philadelphia, Pa: Saunders Elsevier; 2010:chap 65.
David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; and George F. Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program, San Diego, California. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.