Patent GB-115251-A (GB)
Title: Improvements relating to X-ray Localisation.
Inventor: DAVIDSON JAMES MACKENZIE
Filed: 1917-07-07
Abstract: 115,251. Davidson, J. M. March 26. 1917. R÷ntgen-ray apparatus.-In X-ray localization apparatus the X-ray tube, the fluorescent screen, and the cross-wires or the like are mounted in fixed relationship to each other, the whole being adjustable along the line through the cross-wires and the anti-cathode centre, and also, so that two shadows of the foreign body may be obtained, parallel to the screen, means being provided by which the depth of the foreign body may be deter- mined from the displacement of the shadows; means for marking the spot upon the patient's skin beneath which the foreign body is situated, for measuring the distance of this spot from the cross-wires and a stop-plate with a variable aper- ture for adjusting the diameter of the beam may also be provided. As shown in Fig. 1, the tube is movably mounted within a protective box 6, and is supported by an arm 11 secured to a sleeve 10 which carries a pivoted frame 20 supporting the screen and cross-wires. The sleeve 10 is ad- justable vertically by rack and pinion upon an upright 9 secured to a carriage 4 movable trans- versely on a carriage 3 which travels longitudin- ally on rails 2 carried by the table 1 upon which the patient is laid. The apparatus is displaced longitudinally to obtain the two shadows. In a modified construction, Fig. 3, the longitudinal and transverse adjustments are similarly effected, but the tube &c. is displaced transversely to ob- tain the two shadows. The tube is clamped be- tween upper and lower parts 5, 6 respectively of the protective box, and the box is supported by four inclined surfaces 18 upon inclined sur- faces 17 carried by a slider 15, one end of the box engaging an upright piece 19 carried by the carriage 4. The screen &c. is carried by an up- right 10 secured to the box, and vertical adjust- ment is obtained by moving the slider 15 hori- zontally. The tube, screen, &c. may, in a fur- ther modification, be carried by a. stand 23, Fig. 5, mounted on castors, the stand being capable of being fixed relatively to the floor by means of two pins 39 which are lowered so as to touch the floor by springs 40 when nuts 42 on their screwed upper parts are turned simultaneously by means of a connecting cable 44 and a handle 45. The tube box 6 may be hingedly supported on an arm 24 and be secured in any position by a screw clamp 38. The arm 24 is slidably mounted in a sleeve 25 which is itself slidable in a casting 26 vertically adjustable on a vertical tube 27 by a rack 28 and a pinion operated by a handle 29, the casting 26 being attached to a counter- weight within the tube 27 by a wire 30 passing over a pulley 31. Fine adjustments for the posi- tion of the sleeve 25 and the angular position of the casting 26 about the axis of the tube 27 are provided. Displacement of the tube &c. through a known distance to obtain a second shadow is effected automatically in this modification by means of a lever 46 which is pivoted on a ring 49 and has a pin 52 at one end moving in vertical slots 53 under the control of a spring, the ring 49, when the lever is moved, coming into engage- ment with the end of the sleeve 25 and limiting the movement. The cross-wires may comprise two parallel wires W1, W2, Fig. 8, separated by a distance equal to that through which the tube is moved, which are intersected at right-angles by a single wire W and mounted in a frame 56 slidable in the frame 20 by means of a rack and a pinion operated by a wheel 59 having a gradu- ated edge. The first shadow of the object is ar- ranged to fall on the wire W1, and, after displace- ment of the apparatus, the wheel 59 is turned to bring the second shadow P2 on to the wire W2, the depth of the object from the cross-wires being read off from the wheel 59. A scale in fixed rela- tion to the cross-wires giving a direct reading of the depth of the foreign body therefrom may be provided, either as a scale on celluloid or glass on the upper part of the screen, or as a scale formed by notching or perforating the cross-wires themselves. The screen is carried in a frame 61 mounted on the frame 20 by double hinges 62. The spot on the patient's skin beneath which the foreign body is situated may be marked by the point of a rod 164 which is graduated to enable the depth of the spot from the cross-wires to be read and is mounted in a casting 64 which is hinged and provided with a stop arm 65 so that it may be turned into proper position when the screen frame 61 is swung out of the cross-wire frame 56. The top of the protective box may be provided with a slidable plate 66, Fig. 10, having a large aperture registering with an elongated aperture in the top of the box, and having also a number of pivoted steps 67, 68, 69 of various sizes which may be used to vary the diameter of the beam and a pivoted plate 70 by which the beam may be entirely cut off. As indicated in Fig. 5, a pair of binocular magnifying glasses may be mounted above the frame 20 so that the shadows may be observed from one side.