Principle
Barium sulfate is a type of contrast medium that is opaque to X-rays. As the patient swallows the barium suspension, it coats the esophagus with a thin layer of the barium. This enables the hollow structure to be imaged.
This is commonly used with baking soda (sodium bicarbonate crystals) to produce gas (see Reactions of sodium bicarbonate). As gas is low in density, and the X-rays pass through very easily, they will appear as white patches, as opposed to the black produced by relatively dense, X-ray opaque barium. As such, it is extremely useful in providing a contrast to the barium, to produce a double contrast image, to allow better visualisation of the contrasting features within the mucosal layer of the esophagus.
Barium sulfate is an irritant outside the gastrointestinal tract. In cases where a leak is suspected or desired to be demonstrated, contrast imaging involving the use of water-soluble contrast media containing iodine is used.
As with all X-rays, the barium swallow technique employs radiation, and may irradiate the patient unnecessarily. The barium swallow should not be used unless required, and, although it cannot be replaced by endoscopy as for the barium enema, it should be avoided as much as possible for children and pregnant women.
Read more about this topic: Barium Swallow
Famous quotes containing the word principle:
“The monk in hiding himself from the world becomes not less than himself, not less of a person, but more of a person, more truly and perfectly himself: for his personality and individuality are perfected in their true order, the spiritual, interior order, of union with God, the principle of all perfection.”
—Thomas Merton (1915–1968)
“Thus it seemed that this one hillside illustrated the principle of all the operations of Nature. The Maker of this earth but patented a leaf. What Champollion will decipher this hieroglyphic for us, that we may turn over a new leaf at last?”
—Henry David Thoreau (1817–1862)
“Now, what I want is, Facts. Teach these boys and girls nothing but Facts. Facts alone are wanted in life. Plant nothing else, and root out everything else. You can only form the minds of reasoning animals upon Facts: nothing else will ever be of any service to them. This is the principle on which I bring up my own children, and this is the principle on which I bring up these children. Stick to Facts, sir!”
—Charles Dickens (1812–1870)