THE ODELCA ONE HUNDRED MILLIMETER CAMERA AND RAPID FILM-CHANGER: ITS APPLICATION TO ANGIOGRAPHY.

Abstract

It is well recognized that sequential films are necessary for the appreciation of all phases of vessel filling during vascular contrast examinations. This can be accomplished by radiographic and/or photographic reproduction of opacified vessels with any reliable device that records extensive information in a short period of time in serial fashion. An optical camera recording of the fluoroscopic image coupled to a compact, serial cut-film changer permits the recording of images of opacified vessels at rates of up to six films per second. The Odelca film camera and changer3 is such an instrument, with the advantage of mobility when employed beneath a portable examining table. It can be used with any overhead or ceiling-mounted, mobile x-ray tube in any of several adjointing rooms during angiography. Only the x-ray tube and generator capacities effectively limit the total number of exposures that can be made with the system. The camera employs a fixed grid in front of a curved, fluorescent screen which fluoresces when struck by the impinging beam of x-ray photons and sends light impulses through a special condensing mirror system to a curved surface in contact with 100 × 100-mm.-size film. These small individual films are transported serially and rapidly from a light-tight magazine across the aperture of the condensing system at a speed set b y a programming device. The fluorescent are a at the front of the camera covers a total of 14 × 14 in., allowing complete coverage of even large adult fields during thoracic and abdominal angiography. Figure 1 illustrates the camera beneath an examination table during intravenous aortography by the percutaneous catheter technic. The programming device can be set to deliver up to 40 consecutive films at rates of from 1 every two seconds to 6 per second. Different speeds can be selected for each set of 5 sequential films. Because of the small size of the transport mechanism and no need for bulky intricate parts, the film-changer-camera combination suffers little from transport breakdown or mechanical failures, problems more common to larger automatic film-changers when careful maintenance is not practiced. A red light on the side of the camera warns the operator if all preliminary operational steps have not been carried out. This safeguard helps to prevent most operational failures. The only problem encountered during nineteen months of continuous use was an occasional sticking together of the films in the magazine, preventing their transport during operation. To correct this, film packages are opened and stored in a dry dark room. Then, before the magazine is loaded, the individual films are ruffled like playing cards to reduce surface tension associated with slight moisture and to assure dry, separated films. These procedures and careful attention to film positioning in the magazine have prevented film jams during the past several months of operation.