Body-section radiographic equipment; modifications and accessories.

Abstract

Facilities for making body-section roentgenograms of the lungs are now considered a necessary part of the radiographic service of any sizable tuberculosis hospital. Usually a single level is radiographed on a single film, 8 × 10 inches or larger. A number of films are thus obtained, which must be sorted and arranged in sequence before they can be adequately interpreted. Such sorting of films is an unnecessary, time-consuming nuisance. Some have in part eliminated it by making two or four exposures on a 14 × 17-inch film, divided into halves or quarters with lead-rubber masks. (When the film is quartered or halved horizontally, in the usual film-viewing position, it is necessary to invert the cassette for half the exposures on each film.) While the film sorting problem is greatly simplified by this procedure, with existing equipment some of the radiographic images are either reversed or upside down and interpretation is still unnecessarily involved. Since in most instances the region to be examined (at least in the lungs) has previously been fairly well localized, it can usually be adequately covered by one-fourth of a 14 × 17-inch film (7 × 8½ inches, which in the average person will cover about two-thirds of one lung field). If all four radiographic images on a 14 × 17-inch film could be upright, with none reversed, film sorting would be largely eliminated and film storage and interpretation would be greatly simplified. It is the purpose of this paper to describe simple modifications of present body-section radiographic equipment to make this possible, as well as certain accessories that have proved useful to us. Modification 1: The first modification is illustrated in the drawing and photograph in Figure 1. It consists of a substantial brass bar (“latch bar”) which is attached to the Bucky carriage on the back of the table. Brass spacer blocks are permanently fastened to the Bucky carriage, containing indexing pins which engage holes in each end of the latch bar. The latch bar is held in position on the spacer blocks with a single large thumb screw at each end (the thumb screw extending only into the spacer blocks). In the latch bar, toward one end, are three tapered holes on 4¼-inch centers. On the latch bar is mounted a sliding carriage equipped with a spring-loaded tapered pin lock which, in the locked position, engages any one of the three holes in the bar. (The pin lock and holes are tapered to eliminate unwanted play as these parts wear from use.) The latch is at one end of the sliding carriage and is released by a single movement of the handle which, through a short lever and link, pushes a wedge under the head of the spring-loaded tapered pin. Near the other end of the carriage is mounted the Bucky swivel bearing. This swivel bearing engages the lower end of the connecting lever which moves the Bucky carriage (and film) in one direction while the x-ray tube moves in the opposite direction about the fulcrum.