A gallbladder scan is a nuclear scanning test that is done to check gallbladder function. The scan can find blockage in the tubes (bile ducts) that lead from the liver to the gallbladder and small intestine (duodenum). See a picture of the gallbladder and the duodenum .

During a gallbladder scan, a radioactive tracer substance is injected into a vein in the arm. The liver removes the tracer from the bloodstream and adds it to the bile that normally flows through the bile ducts to the gallbladder. The gallbladder then releases the tracer into the beginning of the small intestine. A special camera (gamma) takes pictures of the tracer as it moves through the liver, bile ducts, gallbladder, and small intestine.