Patent GB-881363-A (GB)
Title: Combined image transmission device and x-ray responsive visual image producing meansabove x-ray examination table
IPC: A61B6/10
Filed: 1958-12-23
Abstract: 881,363. X-ray apparatus. PICKER X-RAY CORPORATION WAITE MANUFACTURING DIVISION Inc. Dec. 23, 1958 [July 23, 1958], No. 41438/58. Class 98(1). X-ray apparatus has an X-ray-responsive visual image producing means (such as a fluorescent screen), and an image transmission device (such as an image amplifier), both movably mounted on an examination table, so that either may be moved into the X-ray beam independently of the other. In Fig. 2 the length of the table 20 extends perpendicular to the paper. Mounted below the table, and running on rollers 23, is a carriage 22 supporting an X-ray tube 25. A tower 27 is mounted on carriage 22 by rollers 28, so that the tower can move both along and across the table. Above the table, another carriage 29 is mounted on tower 27 for upward and downward movement thereon. Carriage 29 is formed as a hollow casing; on it is mounted the image amplifier 31 by means of rollers 32, so that the amplifier can be moved from a rearward (inoperative) position, Fig. 10, to a forward (patient-viewing) position (Fig. 9, not shown). Within carriage 29, and just below the amplifier, is a fluorescent screen 33 mounted on rollers 34, which can also be moved to a forward or rear position similarly to the amplifier. In the lower part of carriage 29 is mounted a film-carrying cassette 36 in a tray 35, also mounted on rollers for movement into a forward or rearward position. Movement of the tray 35 is controlled by a motor. Mounted above X-ray tube 25 is a beam-limiting diaphragm consisting of a pair of plates movable towards or away from each other, mounted over a similar pair at right-angles to the first pair. Thus the beam-limiting aperture can be adjusted to a square or rectangle of desired size. Fig. 16 (not shown) is a suitable control circuit for rendering the operation of the apparatus substantially automatic. Thus an exposure cannot be made unless either the fluoroscopic screen or the image amplifier is occupying the forward (operative) position, in which case a release button is engaged. Further, when the amplifier is pulled forward, a portion of its undercarriage engages a button which actuates a switch-over from circuit parameters suitable for the fluorescent screen to parameters suitable for the amplifier. When the cassette tray is in the forward position (in which it is loaded), moving either the amplifier or screen into the forward position automatically causes the cassette tray to return to the rearward position. To counterbalance the weight of the carriage 29 and the equipment thereon, it is attached by a cable 120 to a counterbalancing system secured to the ceiling. This comprises a pair of pivoted arms 108, 109, the latter being hollow and containing an assembly of springs 111. These are fixed at one end 112, and attached at the other to a movable yoke 114; the yoke carries a pulley 115 linked by a cable 118 to a sheave 116 round which it is wound. The cable 120 is also wound round a further part 116b of the sheave 116. In order to increase the range of use of the apparatus, a second X-ray tube 122 is mounted above the examination table 20, and is supported by a telescopic arrangement 123 from a track secured to the ceiling