WO2003024333A1

WO2003024333A1 - A patient support table stand having a pivotable receptor unit

Info

Publication number: WO2003024333A1
Application number: PCT/SE2002/001669
Authority: WO
Inventors: Carl-Eric Ohlson
Original assignee: Ao:S Metall & Mek. Verkstad Ab
Priority date: 2001-09-19
Filing date: 2002-09-17
Publication date: 2003-03-27
Also published as: SE518342C2; EP1435838A1; SE0103100D0; SE0103100L

Abstract

A patient table (20) for radiation detection, e.g. for electronic image storage or X-ray photography, includes a receptor unit (2) carried by an arm and link system (3-9). The receptor unit is mounted in a stand part (1b) which is movable in the Z-direction, wherein the receptor unit is movably carried in the longitudinal direction of said stand part (the X-direction) and is adapted for co-action with a radiation source. The receptor arm and link system (3-9) includes a primary arm (4) mounted on one end of a primary vertical pivot shaft (3), a secondary vertical pivot shaft (5) and a secondary arm (6) mounted on said secondary pivot shaft. Also provided is a tertiary arm (8) which is connected to a second horizontal pivot shaft (9) via generally U-shaped arm parts (8a), said second pivot shaft (9) extending at right angles to the first horizontal pivot axis (7). The receptor can be swung upwards and outwards to different positions on the front and rear sides of the table (20). Means (e.g. 12) are also provided for positively controlling the movements of said arms.

Description

A PATIENT SUPPORT TABLE STAND HAVING A PIVOTAL RECEPTOR UNIT

FIELD OF INVENTION

The present invention relates to a patient support table having a pivotal receptor unit for radiation detection, for example for electronic image storage or X-ray photography, said stand being of the kind defined in the preamble of Claim 1.

DESCRIPTION OF THE BACKGROUND ART

A patient table stand of this kind that includes receptor units which can be swung out from both sides of the table are known to the art, for instance from SE-B 9402589 (AO Medical Products) and its American counterpart US-A 5,764,724 (Ohlson).

This stand and table construction is relatively complex and has the following drawbacks, among others:

1) Three relatively long pivot arms with separate electromagnetic position locks and sensors are required to move the receptor (the bucky) from horizontal positions beneath the tabletop to vertical positions on respective sides of said tabletop.

2) With respect to positioning of the receptor, the degrees of freedom of the three pivotal arms place high demands on safety and on the provision of devices for preventing serious pinching injuries as a result of movement of the receptor and adjustment to the height of the examination table in the vertical plane, particularly when swinging the receptor to positions outwardly of the tabletop. Movements of the pivotal arms to and from outwardly and inwardly swung positions constitute pinching risks of a scissors- like nature.

3) Placement of the table internal and external cables to the receptor unit is made difficult by the different relative positions of the three pivotal arms. The problem thus occurs when drawing cables both inwardly of and outwardly of the pivotal arms. 4) Clinical cleaning requirements are difficult to fulfil as a result of the movable parts of the three pivotal arms in pivot centres, and other relative movement displacements. Particular problems reside in cleaning away blood, urine, contrast agents, etc., from between the movable surfaces and from those parts located outside the table. The multiple functions of the three pivotal arms also require the provision of several covers of complicated shape.

5) When the receptor is swung up to a position above the tabletop, it is desirable that the receptor can be moved from its upwardly swung position to one side of the tabletop in one single manoeuvre, i.e. without needing to first move the receptor vertically. In the case of a number of receptor sizes, this means that the pivot shaft bearing in the horizontal plane in respect of an outwardly swung receptor cannot be located beneath the lower part of the receptor, therewith making rotation of the receptor in the vertical plane difficult to achieve, among other things to change the raster direction or to choose a standing or supine format. In order to provide still a further horizontal axis for an outwardly swung receptor, the receptor can be "tipped up" so as to pass said bearing centre. This further adds to the complexity of the system, among other things with respect to bearings, position locks, sensors, safety, and clinical cleaning.

6) In turn, this drawback results in a limitation in the movement of the upwardly raised receptor in the vertical plane in order to position the lower edge of the image field in the plane of the tabletop.

When planning X-ray examination rooms, a general rule is that radiation is projected in directions away from any door openings present, for safety reasons. A typical examination room includes one radiation source and at least two image receptors, of which one is placed in the examination table for radiation projected in a vertical direction to examine a patient lying on the table, while the other is mounted on a wall stand or floor stand for horizontal radiation projection for examining a standing or a seated patient.

Commencement of the transition from analog to digital technology - which is expected to continue for some decennia - involves comprehensive investments in new equipment and new working routines. In this regard, X-ray film and digital so-called image plates are replaced by direct digital image detectors that generate the images directly to the digital examination station. It is highly desired to minimise the number of expensive detectors used, such detectors being about ten times more expensive than corresponding analog image receptors. However, universal use of one detector per examination room places very high demands on the flexibility in which the receptor can be positioned relative to the radiation source, among other things with regard to adaptation with respect to any door openings that may be present in the room.

The drawback with existing arrangements primarily resides in the difficulty encountered in adapting the direction of radiation with respect to the door openings present in the room, and to obtain the same radiation direction for standing and seated patients, and to be able to perform the same type of examination from both the front side and the rear side of the table.

OBJECTS OF THE INVENTION

One object of the invention is to provide a patient support table stand of the aforedescribed kind with which said drawbacks and disadvantages of known arrangements, and also other drawbacks and disadvantages, are avoided.

Another object is to provide a receptor carrier arrangement that facilitates manual adjustments to the setting of the receptor and also motorised adjustment to said receptor setting, and, when desired, to provide the advantage whereby neither the tabletop supporting the patient nor the radiation source need be moved in the X-direction in conjunction with exposing a given relevant part of the patient's body in both a horizontal and a vertical radiation path.

SUMMARY OF THE INVENTION

These and other objects are achieved with a patient support table stand of the aforesaid kind that includes the features set forth in the characterising clause of the accompanying Claim 1.

The receptor-carrying arm and link system provides a light, flexible and compact unit which simplifies handling of the receptor unit and also swinging said receptor unit upwards and outwards on both sides of the table, while avoiding the drawbacks of the aforedescribed known arrangement at the same time.

Another important advantage is that the direction in which radiation is projected is the same for a standing and a seated patient and can be readily adapted with regard to any door openings present in the room.

The space available to patient and personnel is the same on both the front side and the rear side of the table, regardless of the direction of radiation.

As a result of extending the primary arm, i.e. the length between the primary and secondary pivot shaft or axis, the receptor can be readily swung up to a height above the tabletop that fulfils the requirement of projecting so-called hip axials.

It is also preferred that the second horizontal pivot shaft is located at a selective height relative to the secondary arm, thereby affording a corresponding advantage when this distance is increased in relation to what is normal.

To this end, the second horizontal pivot shaft may be located on generally U-shaped link arms that project up from the secondary arm, and pivotally connected to the tertiary arm connected to said generally U-shaped link arms. The link arms of each pair of generally U- shaped link arms are preferably close together, and preferably so that the U-shaped link arm projecting up from the secondary arm extends outwardly of the generally U-shaped element formed by the link arms of the tertiary arm.

Flexible adaptation to the projection direction of the receptor is made possible when the receptor is supported outside the table at right angles to the longitudinal direction of said table, therewith enabling the receptor to be angled selectively either to the head end or to the foot end of said table. This symmetry also provides the maximum of space at the front and at the rear of the table with regard to patient and personnel in relation to the receptor.

Particular benefits are gained with respect to receptor manoeuvring when, in accordance with one preferred embodiment of the invention, means are provided for forcibly guiding or positively controlling movements of the secondary arm relative to the primary arm. This positive control of said movement is preferably such that when the primary arm is swung through an angle from its starting position, the secondary arm will also swing with a transmission ratio of 1 :2, i.e. through twice the angle from said position.

It is also preferred that the arm and link system is carried by a take-up plate or carriage that can be moved in the X-direction relative to the table. This avoids time-consuming and unnecessary adjustment of the position of the patient and/or the receptor upon transition between frontal and lateral radiation directions. Such adjustment is particularly troublesome when examining badly injured emergency patients, in which case the invention provides simple alternative automatics for retaining the position of the image field relative to the patient.

The take-up or carriage is suitably adapted to carry out positively controlled movement in the X-direction to compensate for movement of the image centre in said X-direction in conjunction with swinging the receptor outwards and upwards.

The means for forcibly guiding or positively controlling movement of the take-up plate may conveniently be mechanical and include link arms and alternatively activatable locking devices, such as adhesion magnets.

The secondary arm positive control means is conveniently embodied in the first arm and includes a gear or belt drive.

The aforesaid receptor take-up arrangement facilitates both manual setting of the receptor and the motorised setting thereof, and, when desired, provides the advantage whereby neither the tabletop supporting the patient nor the radiation source need be moved in the X- direction in conjunction with exposing given relevant parts of the body to both a horizontal and a vertical beam path.

Motorization of the receptor take-up plate may also be combined with so-called electronic tomography. This method of examination is based on the principle of moving receptor and radiation source linearly and proportionally in opposite directions in the longitudinal direction of the table relative to a selective horizontal rotational or pivotal axis above the upper plane of the tabletop. Further characteristic features of and advantages afforded by the present invention will be apparent from the following detailed description of a preferred embodiment of the invention. This description is made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective illustration showing in chain lines a stand which supports a patient table that includes a tabletop, and an arm and link system mounted in a raisable and lowerable stand part for carrying a receptor unit that can be swung outwards and upwards from both sides of the table.

Fig. 2 is a perspective view corresponding to the view of Fig. 1, and shows the receptor unit swung out on the front side of the table.

Fig. 3 is a perspective view corresponding to the view of Fig. 2, and shows the receptor unit swung up to a vertical position about a horizontal axis that is perpendicular to the longitudinal direction of the table.

Fig. 4 is a perspective view corresponding to the view of Fig. 2, and shows the receptor unit swung up to a vertical position in which the bottom edge of said unit is situated above the table surface, said receptor unit being swung about a horizontal axis that is parallel with the longitudinal direction of the table.

Fig. 5 is a perspective view corresponding to the view of Fig. 2, shows the receptor unit swung to an angled position about a vertical axis.

Figs. 6, 7 and 8 are respective plan views of the receptor unit and associated arm and link systems in their positions corresponding to the respective views of Figs. 1, 2 and 3.

Figs. 9, 10 and 11 are respective plan views which show the tabletop, the receptor unit and associated arm and link systems in a number of different alternative positions on the front side and the rear side of the table respectively. DESCRIPTION OF PREFERRED EMBODIMENTS

Figs. 1-5 are perspective views illustrating in chain lines a vertically movable (Z-direction) stand 1 that supports a patient table 20 having a tabletop 20a for radiation detection, for example electronic image storage or X-ray photography.

A receptor unit 2 is supported in the vertically movable stand part by an arm and link system 3-9 and is movably carried in the longitudinal direction (X-direction) of the table on a take-up plate or carriage 21 that can move backwards and forwards in said direction.

The receptor unit is adapted for co-action with a radiation source (not shown) that is movable in at least the transverse direction (Y-direction) and the vertical direction (Z- direction) of the table 20. The radiation source is normally also movable in the X-direction.

The stationary foot part of the stand is referenced la.

The arm and link system that carries the receptor unit 2 includes a primary arm 4 that has one end mounted in a primary vertical pivot shaft 3 connected to the take-up plate 21. Provided at the opposite end of the primary arm 4 is a secondary vertical pivot shaft 5 on which a secondary arm 6 is mounted. The system also includes a tertiary arm 8 which carries the receptor 2 via a pivot shaft 11, wherein said arm is rotatable about a first axis 7 which is horizontal in the starting position and which extends at right angles to the primary pivot shaft 3 and the secondary pivot shaft 5. The tertiary arm 8 is also rotatable about a second horizontal pivot shaft or axis 9 which is connected to the secondary arm and extends at right angles to the first horizontal axis 7. To this end, the second horizontal pivot shaft 9 is provided on generally U-shaped link arms which project up from the secondary arm 6 and which are rotatably connected with generally U-shaped links 8a connected to the tertiary arm 8, via said horizontal pivot shaft 9.

In this respect, the second horizontal pivot shaft 9 is located at a height relative to the secondary arm 6 such as to enable the receptor to be swung up to the position shown in Fig. 4, in which the bottom edge of the receptor 2 is situated above the tabletop 20a. The tertiary arm 8 is connected via the pivot shaft 9 to the U-shaped link arms 8a via a cubic coupling element 8b which accommodates the pivot shaft 7 about which the receptor 2 can rotate.

The arm and link system 3-9 also includes means for positively controlling, primarily movements of the secondary arm 6 relative to the primary arm 4. In the illustrated embodiment, said means are included in the primary arm 4 and, as evident from Figs. 6 and 8, comprise three gearwheels 12a, 12b and 12c, of which the gearwheel 12a is connected to the primary pivot shaft 3 and the gearwheel 12c is connected to the secondary pivot shaft 5. The gearwheel 12b is a small intermediate wheel, which ensures that the two gearwheels 12a and 12c will rotate in mutually the same direction.

The positively controlled movement achieved with the gear system 12 is such that when the primary arm 4 is swung through an angle α from the starting position shown in Figs. 1 and 6, the secondary arm 6 will swing with a gear ratio of 1 :2, i.e. through the double angle 2α from said position.

Fig. 11 illustrates an alternative embodiment in which the gearing 12 is replaced with a belt transmission 13 which includes a wheel 13a connected to the pivot shaft 3 and a smaller wheel 13b connected to the pivot shaft 5, where said wheels are caused to rotate in mutually the same direction with the aid of a drive belt 13c. The positive control and the transmission ratio are, in this case, the same as that achieved with the gearing 12 shown in Figs. 6, 7 and 8.

Fig. 3 shows how the receptor 2, shown in a horizontal, outwardly swung position on the front side of the table in Fig. 2, can be swung around the horizontal pivot shaft or axis 7 so as to bring the major part of the receptor 2 to a position beneath the tabletop 20a. One vertical position of the receptor, e.g. for taking a picture of a seated patient or, e.g., a picture of a knee of a standing patient, is shown in full lines.

Shown in chain lines is an alternative vertical position of the receptor in which said receptor has been rotated in the opposite direction for taking a corresponding picture. The position that is most favourable in relation to the location of door openings in the examination room is chosen in each individual case, and, in practice, the arm and link system may be adapted so that the receptor can be placed in only one of the illustrated two possible positions.

The plan view of Fig. 9 shows in full lines and chain lines respectively the two positions into which the receptor can be placed on one side (the front side) of the table, while Fig. 10 illustrates corresponding positions of the receptor when it is swung out on the other side of said table (the rear side).

Figs. 5 and 8 illustrate how the direction of receptor projection can be flexibly adapted by means of the receptor carrier arms 4 and 6. Thus, the figures show that the receptor can be angled selectively to the head end or the foot end of the table. This symmetry provides a maximum of space for both patient and personnel in the area around the receptor on the front and rear sides of the table.

With the intention of avoiding time-consuming and complicated adjustment of the position of the patient and/or of the receptor in the transition between frontal and lateral direction of radiation, which is particularly troublesome when examining badly injured emergency patients, the inventive arm and link system provides the following alternative automatic system for maintaining the position of the image field in relation to the patient.

The inward and outward pivotal movement of the receptor to a position beneath and outside the table can be utilised to move the take-up plate 21 through the medium of an additional link system (not shown) which is separate to the described arm and link system 3-9 and which is located on the front and rear side of the table, in combination, e.g., with a holding magnet (not shown). The take-up plate 21 is connected to the arm and link system via the primary pivot shaft 3, and is displaced in the longitudinal direction (the X- direction) of the table. The arrangement is based on the interaction between the holding magnet of the additional link system and a corresponding holding magnet (not shown) for the take-up plate 21, and the function of a manoeuvring handle (not shown) for releasing position locks provided for the different positions of the receptor.

Normally, all link magnets and carrier magnets are engaged. However, all magnets are disengaged, or deactivated, when moving the take-up plate 21. The take-up plate magnet and uninvolved link magnets are deactivated when swinging of the receptor is commenced. The floor-plate magnet and uninvolved link magnets are activated, or engaged, when swinging of the receptor is terminated.

A corresponding function can be achieved by providing the take-up plate with a drive means, for instance an electric motor. When the inward and outward movements of the receptor are also detected with the aid of continuous analog or digital position sensors, e.g. potentiometers or pulse sensors, the motor drive can be reversed and adapted to follow the speed of the receptor as it swings.

It is also possible to allow movement of the take-up plate to attend to swinging of the receptor when the manoeuvring device of said plate is activated. Because the two movements are counter-directional, the operator need only "restrain" movement of the take-up plate. For the sake of safety, this manoeuvre will preferably have the function of a "dead man's grip".

Motorization of the take-up plate may also be combined with so-called electronic tomography. This examination method is based on the principle of moving image receptors and radiation source linearly and proportionally in opposite directions in the longitudinal direction of the patient table relative to a selective horizontal pivot axis above the upper surface of the tabletop.

In summary, both the arm and link system 3-9 for moving the receptor 2 and/or the positive movement control means 12 or 13 for the secondary arm 6 and the take-up plate 21 respectively may be equipped with an electric motor drive.

The person skilled in this art will realise that embodiments other than those described above are possible within the scope of the inventive concept as defined in the accompanying Claims.

Claims

1. A patient support table stand (1) having a receptor unit (2) for radiation detection, e.g. electronic image storage or X-ray photography, wherein said receptor unit is mounted in a vertically movable (Z-direction) stand part (lb) and is movably carried in the longitudinal direction (X-direction) of said stand part and adapted for co-action with a radiation source that is movable in at least two directions at right angles thereto (the Y- direction, i.e. the transversal direction of the table, and the Z-direction), and is adapted at least for a vertical and horizontal beam path, wherein the receptor unit (2) can be swung outwards and upwards from a starting position for a vertical radiation path beneath the tabletop (20a) to alternative positions for horizontal and/or vertical radiation paths on respective sides of said table, characterised in that the receptor (2) is carried by an arm and link system (3-9) which includes a) a primary arm (4) whose one end is mounted on a primary vertical pivot shaft (3); b) a secondary vertical pivot shaft (5) mounted on the opposite end of the primary arm(4); c) a secondary arm (6) mounted on the secondary vertical pivot shaft (5); d) a tertiary arm (8) having a part (8c) which carries the receptor (2) either directly or indirectly and which is rotatable about a first pivot axis (7) which is horizontal in the starting position and which extends at right angles to the primary and the secondary pivot shaft (3; 5); and where e) said tertiary arm is also rotatable about a second horizontal pivot shaft (9) which is connected to the secondary arm and which extends at right angles to said first horizontal pivot axis (7) and which is located so that the receptor can be swung up to a position in which its bottom edge is situated above the tabletop.

2. A stand according to Claim 1, characterised in that the second horizontal pivot shaft (9) is located at a selective height relative to the secondary arm (6).

3. A stand according to Claim 2, characterised in that the second horizontal pivot shaft (9) is mounted on generally U-shaped link arms (6a) which project up from the secondary arm (6) and which are pivotally connected, via said horizontal pivot shaft (9), to generally U-shaped link arms (8a) connected to said tertiary arm (8).

4. A stand according to any one of Claims 1-3, characterised by means (12; 13) for positively or forcibly guiding the movements of said secondary arm (6) relative to movements of said primary arm (4).

5. A stand according to Claim 4, characterised in that said forced or positive guidance is such that when the primary arm (4) is swung through an angle (α) from its starting position, the secondary arm (6) will swing at a transmission ratio of 1:2, i.e. through the double angle (2α) from said position.

6. A stand according to any one of Claims 1-5, characterised in that the arm and link system (3-9) is carried by a take-up plate (21) which can be moved in the X-direction relative to the table (20a).

7. A stand according to Claim 6, characterised in that the take-up plate (21) is adapted to carry out positively controlled movements in the X-direction to compensate for movement of the image centre in the X-direction in conjunction with outward and upward swinging of the receptor (2).

8. A stand according to Claim 7, characterised in that the means for positively controlling movement of the take-up plate (21) are mechanical and include link arms and alternatively activatable locking means, e.g. adhesion magnets.

9. A stand according to Claim 4 or 5, characterised in that the means for positively controlling movement of the secondary arm (6) are included in the first arm (4) and comprise a gear or belt system (12, 13).

10. A stand according to any one of the preceding Claims, characterised in that the arm and link system (3-9) for receptor movement and/or the means (12, 13) for positive control of the secondary arm (6) and the take-up plate (21) respectively include an electric motor drive.