radiography

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Branch of science concerned with the use of radiation (particularly X-rays) to produce images on photographic film or fluorescent screens. X-rays penetrate matter according to its nature, density, and thickness. In doing so they can cast shadows on photographic film, producing a radiograph. Radiography is widely used in medicine for examining bones and tissues and in industry for examining solid materials; for example, to check welded seams in pipelines. The field has been transformed by the technique of computed tomography, in which X-ray images produced in numerous scans are combined by computer to form a false-colour image of the three-dimensional structure of internal organs.

Black and red recall the tunics worn by soldiers during the Napoleonic wars. Gold was added to create a flag similar to the French tricolour, a symbol of revolution. Effective date: 23 May 1949. >>