Patent GB-520432-A (GB)
Abstract: 520,432. Surgical optical instruments ; R÷ntgen-ray apparatus. CHAUSSE, C. S. Oct. 17, 1938, Nos. 29974 and 29975. Convention dates, Jan. 14 and May 4. [Class 81 (ii)] [Also in Group XX] R÷ntgen-ray apparatus employed in locating foreign bodies in the human body and comprising a tube 2 adjustable on a rod 3 turntable about a plate-supporting table 5, is combined with light-projection apparatus one or more beams from which, impinging on the surface of the patient's body, act to indicate to the surgeon the direction and depth of the incision to be made. A single'source 6, directing a parallel or slightly convergent beam of light, may be securable in front of the tube 2 by screws 8 or may be used in conjunction with a second source 62 rotatably mounted upon the tubecarrying arm x, or, as shown, upon an adjusting screw 14 and adjacent a scale 16 on said arm. In the first case, the depth, a, of the foreign body beneath the body surface being determined, the beam 9<SP>2</SP> from source 6<SP>2</SP> is first made to coincide, at the body surface, with the beam 9 from source 6, and then the arm x is lowered a distance a; in the second case (shown), the source 6<SP>2</SP> is lowered a distance a after adjustment of its beam 9<SP>3</SP> as above. In both cases the beams 9, 9<SP>2</SP> throw on to the body spots of light which guide the surgeon to the foreign body and coincide thereon. The source 6<SP>2</SP> may be revolved with the rod 3 around tube 2 without modifying its effective setting, the light spot produced by it merely revolving around the central light spot. In a modification, two or more light sources spaced laterally from the tube 2 may be angularly adjusted to settings, indicated by appropriate scales, in which their beams are so directed as to intersect at the foreign body, and consequently show spaced light spots on the body surface, which approach one another as the incision progresses and coincide on the foreign body itself. Instead of several light sources a single source placed above the tube and co-operating with spaced and rotatable mirrors settable with the aid of scales and pointers may be employed. In order to reposition the patient correctly after some undesired movement, a lamp 6<SP>3</SP> mounted on a swinging arm 21, may be employed to throw a beam in succession on to several widely spaced parts of the body, which parts are marked with a dermographic pencil. In order to determine the depth of the foreign body the following procedure may be adapted. A suitable marker, g, Fig. 13, such as lead cross wires, is placed in the path of the R÷ntgen-ray beam and, after a trial exposure on a-ruled plate, the patient's position is adjusted to bring the foreign body d into the axis of the beam. A second marker i is then placed at the point of incidence on the body of a light beam from a source such as 6, Fig. 6. Two exposures are then made on the same plate f with the tube b in the position shown and in a position resulting from a given angular displacement thereof about the centre of the plate. The displacement on the plate of the images of the body d and the marker i, in conjunction with the known displacement of the tube and its distance from the plate, can be used to calculate, or to read off by placing the plate directly over a previously-prepared transparent graph, the heights of the body d and the body-surface marker i from the plate. Instruments employed in extracting the body d may have a terminal mirror set at right angles to their axes, the correct direction of their use being indicated by the light from a guiding beam employed falling on to the mirror. A graduated probe so constructed is described. A direction and depth-gauge is also described comprising a narrow tube having exteriorly a cursor and graduations, the, tube, on insertion into the wound, indicating the correct direction of operation when the light-beam employed passes through it and illuminates the incision made. Specification 503,040, [Group XX], is referred to.