Gastric band treatment for obesity. Frontal X-rays of the digestive system of an obese 57-year-old woman who has been fitted with a gastric band that is being tested before (left) and after (right) a barium meal. The oesophagus, stomach and duodenum (first part of the intestines) are being examined on the X-ray using the contrast medium barium (a 'barium meal') that is opaque to X-rays. The test is known as an oeso-gastrointestinal duodenal transit (OGDT). The contrast medium here shows a satisfactory gastro-duodenal passage of food, with the gastric band reducing the capacity of the stomach.