3. Modified barium swallow-While standing or sitting, the patient swallows 1/2 teaspoon of flavored barium (a radioactive substance) six times (a total of 3 teaspoons), while the tongue and pharynx (tube leading from the mouth to the esophagus) are scanned and videotaped. The barium is given in three consistencies-thin, medium and thick (pudding-like).