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:
“Why does philosophy use concepts and why does faith use symbols if both try to express the same ultimate? The answer, of course, is that the relation to the ultimate is not the same in each case. The philosophical relation is in principle a detached description of the basic structure in which the ultimate manifests itself. The relation of faith is in principle an involved expression of concern about the meaning of the ultimate for the faithful.”
—Paul Tillich (1886–1965)
“There is a good principle which created order, light, and man, and an evil principle which created chaos, darkness, and woman.”
—Pythagoras (c. 572–497 B.C.)
“Country people do not behave as if they think life is short; they live on the principle that it is long, and savor variations of the kind best appreciated if most days are the same.”
—Edward Hoagland (b. 1932)