GB708993A - Improvements in or relating to dental radiography - Google Patents

Abstract

708,993. X-ray apparatus. BERGHAGEN, N. April 25, 1952 [April 26, 1951], No. 10443/52. Class 98(1) Apparatus for dental radiography, in which a film holding device including a film cassette holder mounted on a rod is adjustably arranged on a rod carrying member which is arranged in a fixed position, or is capable of being fixed, relatively to the anti-cathode and the X-rayv cone, and in which the film holding device is adjustable relatively to the rod carrying member so as to be adjustable into different positions along a line parallel to the plane of the film cassette holder and extending at right-angles to the central ray and the axis of the X-ray cone, is characterized in that the rod carrying member is provided with slits or apertures adapted to receive the end of the cassette holder rod and arranged in the same plane in a row along a line perpendicular to the axis of the X-ray cone. As shown, a film holder consisting of a plate 1, with upturned edges 2 for holding a film cassette, is mounted on a bent plate 4, which in turn is fixed to an arm 6 of a plate bent at right-angles. The other arm 7 is pivoted to an arm 8 by means of a bolt 13 which can be tightened to clamp arm 7 at any desired angle to arm 8, this angle being indicated by a scale on a member 16. Arm 8 is clamped in a holder 18, which is mounted on a ring 21 sliding on a ring 20 on a cone 19 of an X-ray tube. Ring 21 may be clamped in any position of rotation. Holder 18 has a number of rectangular-sectioned slots, equally spaced apart and parallel to the axis' of cone 19, into any one of which the squared end of rod 8 may be placed to abut against the end of the slot, the slot ends all lying in a plane perpendicular to the axis of cone 19. A locking member 30 bears cam surfaces, e.g. conical, one to each slot, and a threaded end which screws into a part of holder 18 to clamp rod 8 in whichever slot it occupies. The apparatus enables radiographs to be made in two or more positions which are fixed with respect to the X-ray tube, the shadows of a raised point 31 and the edges 2 acting as reference marks. The radiographs may be used for stereo-radiography, or for finding the position of internal features of objects by methods similar to those used in photogrammetry. The apparatus illustrated is designed for dental use. The patient bites the plate 4, which is overlaid with a plastic substance, so that the cassette lies behind the teeth to be examined.