MODEL RELEASES AVAILABLE. Woman undergoing barium meal X-ray examination, showing her drinking a suspension of the barium meal through a straw whilst lying under the X-ray machine. A barium meal is a suspension of barium sulphate that is used as a radio-opaque contrast medium in radiography of the oesophagus, stomach & intestine. Here, radiographer and patient are following the passage of the medium on a monitor linked to the digital X-ray system. Photographed at The Princess Grace Hospital, London.