Barium X-Rays (Upper and Lower GI) A barium X-ray is a radiographic (X-ray) examination of the gastrointestinal (GI) tract. Barium X-rays (also called upper and lower GI series) are used to diagnose abnormalities of the GI tract, such as tumors, ulcers and other inflammatory conditions, polyps, hernias, and strictures. Click Image to Enlarge.