Patient's Couch For Radiological Radiation

Abstract

A table for supporting a patient during radiological treatment, the table having first and second surfaces longitudinally spaced apart defining between them a transverse gap, and a beam connecting and supporting the second surface with the first surface, the beam being movable between different transverse positions in the gap area to provide unimpeded radiation.

Description

In radiological treatment of patients with X-rays or gamma-rays it is common practice to vary the direction of the beam striking a body part to be treated, in order to concentrate the dosage of radiation at a given place in the body, whereas ambient tissue is affected to a lesser extent. A known device for carrying out the radiation in this way is the rotation-therapy apparatus comprising a radiation source adapted to move along the circumference of a circle, the beam of rays being invariably orientated towards the center of the circle. The radiation source may be moved continuously along the circumference of the circle, but the radiation is often directed in different ways while the source stands still during radiation. A further possibility resides in the displacement of the radiation source with respect to the plane of radiation at right angles to the rotary axis on either side over a given distance, while by turning the source, the beam remains directed to the point of intersection of the rotary axis and said plane.

By means of the couch the patient to be treated is moved in the reach of the radiation source (circular or cylindrical plane). In order to provide sufficient space for the movement of the radiation source, the couch top is supported at one end by a supporting column, whereas the other end extends in self-supporting fashion in the space of irradiation. The required rigidity is obtained by arranging the table top on a longitudinal girder, for example, a hollow beam of semi-elliptical section with a flat top surface. The quantity of material thus moved into the radiation beam leads to attenuation of the radiation by absorption when the beam is orientated so that the rays have to penetrate through the table before reaching the region of the body to be irradiated.

There is known a patient's couch having coverable openings in the table top structure so that attenuation of the radiation in given directions is avoided. A greater freedom in selecting the disposition of the radiation source is provided by a further known couch whose bearing top is divided by a void into two bearing surfaces which are separated from each other and in the longitudinal direction of the couch are in line with each other, the connection between the bearing surface being established by a stationary supporting beam. Due to its fixed position this supporting beam may be a source of trouble in some cases, when radiating from below, for treating regions in the vicinity of the vertebral column, so that the patient has to be displaced laterally over the couch top. This disadvantage is reduced in a further known couch in which the portions of the bearing top are interconnected by movable supporting beams, which are provided with orthogonal side arms with stub shafts, which are rotatably journaled in bushed fixed to the bottom sides of the bearing surfaces. By turning the supporting beams around the stub shafts in the bushings, the place and the transverse size of the free space between the supporting beams can be changed so that the rays can pass unhindered. Nevertheless a quite real restriction of the space angle in which the source for upward radiation can be arranged is not obviated in this way.

The present invention has for its object to obviate this restriction as far as possible. In the new patient's couch the bearing top consists of two supporting surfaces separated from each other by an intermediate space and interconnected by a supporting beam having side arms at both ends; to these arms stub shafts are secured which extend parallel to the supporting beams, and are journaled in bearing cradles fastened to the supporting surfaces. A mechanical coupling is provided between the two supporting surfaces as well as a shaft adapted (i) to turn in the supporting beam and (ii) to transfer the angle of rotation of the supporting beam relative to one supporting face in the opposite sense to the other supporting surface.

An appropriate mechanical coupling comprises semicircular toothed rims fastened to the two supporting surfaces, the teeth being in mesh with pinions, which are rigidly connected with each other by an uninterrupted shaft inside the supporting beam. The mechanical coupling may be alternatively formed by chains passed around chain sprockets at the ends of the shaft passing through the supporting beam and around serrated discs fastened to the supporting surfaces. Other known energy transmission gears, for example, comprising ropes or steel belts, may also be employed.

The drawing illustrates particularities of a patient's couch in accordance with the invention, in which

FIG. 1 is a perspective view of such a couch,

FIG. 2 is a fragmentary view of a mechanical coupling comprising meshing teeth,

FIG. 3 is a fragmentary plan view of the couch,

FIG. 4 is a side elevation view thereof,

FIG. 5 is and end view thereof, and

FIG. 6 shows a variant of the mechanical coupling.

The patient's couch of FIG. 1 comprises a supporting column 1, to which one supporting surface of the couch top is secured, which is formed by the supporting surfaces 2 and 3. The two supporting faces are separated from each other by a clearance space 4 and interconnected by a supporting beam 5, provided at each end with a transverse arm 6 and 7 respectively, which are rotatably journaled by means of stub shafts to be described hereinafter in bearing bushings fastened to the supporting surfaces.

The supporting surfaces 2 and 3 are provided with semicircular toothed segments 8 and 9 respectively (FIG. 2). The teeth of the segments are in mesh with the pinions 10 and 11, which are each fastened to one end of a common shaft 12. The shaft 12 is rotatably journaled in a bore in the supporting beam 5 so that the pinions 10 and 11 are rotatable in common and not rotatable separately. The engagement between the teeth of the pinions and the segments renders the supporting beam 5 rotatable about the stub shafts 13 and 14, while the mechanical coupling prevents a displacement of the supporting surface 3 with respect to the supporting surface 2 held by the supporting column 1.

The supporting beam 5 with the two side arms 6 and 7 and the stub shafts 13 and 14 secured thereto provides the required rigidity for the connection of the self-supporting surface 3 with the supported surface 2 because the stub shaft 13 beneath the supporting surface 2 is held in a bushing 15 in the circular toothed segment 8 and in a second bushing 16 in a bearing block 17 secured to the supporting surface 3, whereas beneath the supported surface 2 in the circular toothed segment 9 and in a bearing block 18 secured to said surface bearing bushings 19 and 20 are provided for holding the other stub shaft 14. (FIGS. 3, 4, 5). The supporting beam 5 is illustrated in these Figures in a horizontal position on one side, but by turning it about the stub shafts 13-14 through an angle of 180.degree. it can be moved into the horizontal position on the other side, while the beam can occupy any intermediate position, while the pinions 10-11 roll along the toothed segments 8-9 so that they prevent fatigue of the self-supporting surface 3. The supporting surfaces 2 and 3 are shown in the simplest form, which does not mean to exclude other known form for increasing the bearing capacity.

Another device corresponding to the desired mechanical coupling comprises chains replacing the toothed rims and providing a less rugged construction of relatively lower weight (FIG. 6). For the sake of clarity the supporting surfaces are not shown in this Figure; they are supposed to be provided with bearing cradles 21 bolted thereto and comprising bushings 22. On one side the cradles serve for journaling a stub shaft 13, fastened to one of the side arms 7 of the supporting beam 5 and on the other side the cradles serve for journaling the second stub shaft 14, connected with the other side arm 6 of the supporting beam 5. The two bearing cradles, arranged at a short distance from the side arms, have rigidly connected with them a circular guide disc 23 and a shaft 12 is taken through the supporting beam 5 and is provided at each end with a chain sprocket 24. An endless chain 25 is taken along each of the guide discs 23 and each of the chain sprockets 24, the chain being secured against displacement around the guide discs by a safety pin 26, fastened to the bearing cradles and penetrating in a link of the chains. Consequently a turn of the supporting beam 5 about the two stub shafts does not affect the relative positions of the supporting surfaces with which the cradles are connected.

For closing the opening 4 between the two supporting surfaces 2 and 3 the self-supporting surface 3 may be provided with a displaceable cover 27 (FIG. 1).

Claims

What is claimed is:

1. A patient's couch for radiological treatment comprising a patient-supporting surface formed by two sections disposed in longitudinally spaced relationship, thus defining between them a transverse gap of separation, a junction unit which connects the two sections and is formed by a beam disposed longitudinally in said gap, an arm extending laterally from each end of the beam, from each arm a stub shaft extending generally parallel to and spaced from the beam axis, and a cradle secured to each of said sections, each cradle including bearings for receiving and supporting one of said stub shafts, whereby the beam is pivotable about said shafts and thus movable transversely in the gap, and means for maintaining said sections in a co-planer relationship, independent of the adjustable position of the beam.

2. Apparatus according to claim 1 wherein said means comprises a main shaft rotatably disposed in said beam, each end of the shaft engaging one of said sections.

3. Apparatus according to claim 2 wherein the first section has a generally fixed orientation, and rotation of said means in one direction about the stub shaft engaging said first section, cause equal rotation of the second section in the opposite direction about the other stub shaft, whereby the second section is maintained co-planer with the first section.

4. Apparatus according to claim 2 wherein each cradle comprises a semicircular element with teeth on the curved periphery, and said main shaft has a pinion on each end engaging the teeth of one of said cradle elements.

5. Apparatus according to claim 2 wherein each cradle comprises a nonrotatable sprocket, and said main shaft has a sprocket on each end, and the apparatus further comprises a chain engaging each cradle sprocket and one main shaft sprocket.

6. Apparatus according to claim 1 further comprising a cover positionable to bridge the gap between said spaced sections.

7. A patient's couch for radiological treatment comprising a stand, a first patient-supporting section fixedly secured to the stand, a second patient-supporting section longitudinally spaced from the first section defining a transverse gap therebetween, a junction unit connecting the two sections, the unit including first and second stub shafts rotatably engaged to the first and second sections respectively, and a beam extending between and connecting the stub shafts, whereby the junction unit is cantilever-supported by the first section and the second section is cantilever-supported by the junction unit, the beam being pivotable about said stub shafts and thus movable transversely in the gap.