The Study of the Heart Action with the Roentgen Cinematograph

Abstract

CINEMATOGRAPHIC roentgenography of the human heart has been accomplished by two principal methods. Photographing with cinema films the image on the fluorescent screen was first accomplished (1) and recently brought to a high degree of perfection (2) by Lomon and Commandon. Full-size roentgenograms of the human heart, taken at fixed instants in the cardiac cycle (3, 4) or in rapid succession (5, 6) have not been of great value until Ruggles (7), with the assistance of Mr. E. P. Fletcher, designed and operated a machine taking fifteen 8×10 in. instantaneous roentgenograms per second. The cinematographic positive prepared by them left nothing to be desired in the sharpness of projection of the motions of the heart, but it is questionable if such a method has any advantage over that of Lomon and Commandon for demonstration or preservation of fluoroscopic findings. Its disadvantage, for such work, is the greater cost and difficulty of operation. For the more important purpose of analyzing the action of the normal and diseased heart the method of Ruggles is indispensable, for it is impossible to measure accurately films in which the borders are even slightly blurred, as occurs in full-size projections of photographs of the fluorescent screen image. Thanks to the generosity of Dr. Ruggles, of the University of California, we have had an opportunity to measure his original films of the normal heart and to use his machine, with the assistance of Mr. Fletcher, to obtain for similar analysis films of the moving heart border in cases of valvular disease. The Machine of Ruggles and Fletcher Regular Eastman Superspeed Duplitized X-ray Film, in strips 8 inches wide and 30 feet long, is drawn through the exposure frame by rubber-covered rollers for a distance of eleven inches, while a mechanism of eccentrics and connecting rods holds the two intensifying screens apart and releases a pair of brake shoes designed to prevent movement of the film during the making of each exposure. When the film has moved eleven inches, the rubber-covered rollers no longer grip it firmly between them, for they are broadly notched, and the brakes are at this instant applied to the edges of the film. The intensifying screens are then forced together, and the new area of film is in place and ready for exposure. The above train of events occupies a total time of approximately 1∕24 second. During this interval the high tension line between the X-ray machine and the X-ray tube has been disconnected by a high tension oil-immersed switch, interposed in the anode line. This switch is operated by a shaft from the rollers which move the film. At the instant that the intensifying screens make contact with the film, the high tension oil-immersed switch closes, remaining so for 1∕40 second.