Which procedure specifically involves the use of barium?

The procedure that specifically involves the use of barium is the Upper GI series. This imaging study utilizes barium sulfate, a contrast material, which is ingested by the patient. The barium coats the lining of the esophagus, stomach, and the first part of the small intestine. This coating helps to enhance the visibility of these structures during X-ray imaging, allowing for better identification of abnormalities such as ulcers, tumors, or blockages.

In contrast, other procedures such as a cholecystogram focus on the gallbladder and do not utilize barium, while ERCP (Endoscopic Retrograde Cholangiopancreatography) involves a different type of contrast dye specifically for the bile ducts and pancreas, and ultrasound relies on sound waves rather than contrast materials for imaging. Thus, the use of barium is distinctive to the Upper GI procedure, making it the correct choice in this context.