ROUTINE GASTROINTESTINAL SERIES WITH A 70-MM. SEQUENCE CAMERA.

Abstract

Sophistication of cinefluorographic equipment has led to the adaptation of a 70-mm rapid sequence camera which permits individual exposures as well as sequence exposures, ranging from 1.5 to 10 per second. This camera has great versatility and may be used for individual exposures in spot-films, with detail approaching that of a standard radiograph. In addition, motion may be studied by the sequence features of the camera. In view of these two aspects it lends itself uniquely to upper gastrointestinal tract study. Janker in 1956 (4) was the first to report a 70-mm. record through an image intensifier. Feddema, in 1961 (1), at the Third Rochester Symposium on Cinefluorog-raphy, presented his experience making single exposures with 70-mm. fluorography on a remotely controlled ring stand utilizing a 9-in. intensifier. The present camera is an adaptation which permits sequence studies as well as individual exposures. Stauffer et al. (8) and Simon and Greenberg (6) have also reported their experiences with individual 70-mm studies. The x-ray equipment (Fig.1) is a conventional 125-kv, 500-ma unit with a radiographic, fluoroscopic tilt table. The Philips 9-in. image intensifier with X 3,000 intensification is equipped with an optical viewer, a 16-mm. Arriflex cine camera, and a Hulcher 70, model 102 camera, especially modified and adapted. The 16-mm. camera is equipped with a ƒ 1.8 lens while the 70-mm. camera has a ƒ 4.5 lens, both with appropriate focal lengths. The 70-mm. camera is of relatively light construction and uses Kodak Cinefiure double perforated film, on 100-ft. spools, with ASA-II perforations. The frame rate of 3 to 20 per second has been adjusted to 1 ½ to 10 per second in addition to single-frame work. Frame size is 2 1/4 in. high and 2 ½ in. wide. The shutter has been removed as superfluous, in order to reduce weight. Relative shutter opening is 70°, allowing a maximum exposure time of approximately one-tenth of a second at 1 ½ frames per second, down to one-sixtieth of a second exposure time at 10 frames per second. Special provisions of the camera are electrical contacts to start the x-ray exposure. In a single-shot operation, the exposure is terminated through a phototimer controlled via a light pickup on the image intensifier. Rapid sequence operation can be followed by the Amplimat up to six per second. If a higher sequence rate is desired, the exposure has to be terminated by a preset x-ray timer. Camera speed is controlled by means of a centrifugal electric governor adjusted by a control on the camera. An internally mounted dial indicates the amount of film remaining on the supply spool. The camera stops quickly after each single shot or rapid sequence because of a built-in brake. A special relay box (Fig.2) is provided for automatic film transport after each exposure in a single-frame operation.