Photoroentgenography in a Tuberculosis Program

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A short time after the discovery of the roentgen rays, various attempts were made to photograph the fluoroscopic image direct from the fluoroscopic screen. Most of these failed for one reason or another. In recent years, however, similar attempts have been more or less successful. Several good motion pictures have been made of various parts of the body, particularly those showing involuntary motion, as the chest, heart, stomach, intestines, etc. One of the greatest handicaps to be overcome was exposure time. The results obtained from motion pictures focused attention on other fields, the principal one being so-called miniature radiography for chest survey work. The factors which led us to believe that satisfactory diagnostic results might be obtained on an economical basis include the following important contributions: (1) perfection of x-ray tubes; (2) improvement in fluorescent screens; (3) application of scientific advances made in the optical art; (4) improvements in film emulsions; (5) improvements in transformers; (6) building of condensers. De Abreu of Rio de Janeiro should be given credit for first applying this method, in 1936, to a large number of persons in a survey. He employed a Contax camera to photograph the fluoroscopic image on a 35-mm. film. Janker and Ulrici of Germany used this technic quite extensively and it is being widely employed in that country today. Lindberg, in America, has adopted De Abreu's technic with some modifications. The Westinghouse X-ray Division has recently announced a new photofluorographic unit, utilizing the 35-mm. film. The U. S. Navy at Norfolk, Virginia, is experimenting with photoroentgenography, using the 35-mm. film with a Leica camera. The patient sits on a hydraulic stool, which is raised up and down for various heights; the instrument is kept stationary. Development of the 4 × 5 Inch Film It is known that the use of the regular x-ray film is the most acceptable means for obtaining diagnostic results of the highest quality, but its cost in group examinations of considerable number is a factor which limits survey work. Potter, working with the General Electric Corporation, after much study and experimentation arrived at the conclusion that the most desirable objective in photography of a fluoroscopic image should be the production of a film small enough to constitute economy in celluloid and yet large enough to be readily interpreted without enlargement, or at least no greater magnification than that provided by a simple reading glass. The 4 × 5 inch film was found to be the optimum size. The fluorescent screen used is nearly seven times as fast as the usual Patterson screen; it fluoresces with the most intense blue-violet light obtainable today. It is mounted in front of a light-tight box a yard long, which tapers down to receive lenses and cameras behind. At the back of the screen is mounted a lead-glass plate 2 mm. in thickness to protect the films from x-ray fog.