WO2000009015A1

WO2000009015A1 - Compression device

Info

Publication number: WO2000009015A1
Application number: PCT/SE1999/001338
Authority: WO
Inventors: Lena Harning
Original assignee: Lena Harning
Priority date: 1998-08-11
Filing date: 1999-08-06
Publication date: 2000-02-24
Also published as: SE9802702D0; AU5662699A; SE512953C2; SE9802702L; EP1105043A1

Abstract

The present invention relates to a compression device in connection with x-ray examinations, said device comprising a frame (1) that support means (9; 9') to compress an area of a body of a patient, said area preferably being the abdomen. In connection with x-ray examinations it is important to be able to compress a portion of an examined body of a patient. By such an arrangement the absorbed dose may decrease and a better quality of the x-ray photographs is achieved. The compression device according to the present invention is characterized in that the compression device comprises a fastening means (3), by which the frame (1) of the compression device may be detachably mounted on an examination table (5), and a manually operated displacement mechanism in order to displace the compression device (9) relative to the frame (1) in two opposite directions.

Description

Claims

1. Compression device intended to be used in connection with x-ray examinations, said device comprising a frame (1; 1') that support means (9; 9') to compress an area of a body of a patient, said area preferably being the abdomen, c h a r a c t e r i z e d in that the compression device comprises a fastening means (3; 3'), by which the frame (1; 1') of the compression device may be detachably mounted on an examination table (5; 5'), and a manually operated displacement mechanism in order to displace the compression device (9; 9') relative to the frame (1; 1') in two opposite directions .

2. Device according to claim 1, c h a r a c t e r i z e d in that the compression means constitutes a compression plate ( 9 ; 9 ' ) .

3. Device according to claim 1 or 2 , c h a r a c t e r i z e d in that the fastening means (3; 3') is intended to co-operate with a longitudinal edge of the examination table (5; 5') .

4. Device according to any of the claims 1-3, c h a r a c t e r i z e d in that the frame (1; 1') is box shaped, and that the displacement mechanism is provided inside said frame (1; 1' ) •

5. Device according to claim 4, c h a r a c t e r i z e d in that the displacement mechanism comprises a gear rack

(14; 14'), a carriage (16; 16') displacable along the gear rack (14; 14'), a gear pinion (19; 19') that cooperates with the gear rack (14; 14'), said gear pinion (19; 19') being supported by the carriage (16; 16'), that the compression means (9; 9') also is supported by the carriage, and that the gear pinion (19; 19') is rotated by means of a manually actuated means (7; 7') . 13

6. Device according to any of the claims 1-5, c h a r a c t e r i z e d in that the displacement mechanism comprises means (50') to restrict the force that the compression plate (9') exerts on the patient.

7. Device according to claim 5, c h a r a c t e r i z e d in that the manually actuated means constitutes a crank (7) or a control handle (7 ' ) .

8. Device according to claim 5 or 7 , c h a r a c t e r i z e d in that the gear pinion (19; 19') is provided with a non-return stop for at least one rotational direction of the gear pinion (19; 19') .

9. Device according to any of the claims 6-8, c h a r a c t e r i z e d in that the carriage (16) is guided inside the frame (1) by ball bearings (17) and sliding rails (18) .

10. Device according to claim 2, c h a r a c t e r i z e d in that the compression plate (9; 9') is manufactured from a plastic material reinforced by graphite yarn.

COMPRESSION DEVICE

Technical Field of the Invention

The present invention relates to a compression device intended to be used in connection with x-ray examinations, said device including means to compress an area of a body of a patient, said area preferably being the abdomen.

Prior Art In order to decrease the absorbed dose and to achieve a better quality of the x-ray photographs it is stated in the pending standards (EU) that compression is to be executed of the part of a body of a patient that is to be x-rayed.

From DE-AS-1 942 490 a compression mechanism of a device for x-ray examination is previously known. Said compression mechanism is fixedly connected to the foundation that supports the patient. The compression mechanism includes a frame located on one side of the foundation of the patient, a motor, a displacement means and a plate. By activating the motor the plate may be displaced towards or away from the patient, the displacement of the plate being executed via the displacement means that is movable along the frame. Said compression mechanism is stationary and constitutes a permanent part of the examination device. From SE-B-463 344 a compression device for x-ray and similar examinations is previously known, said device including a belt, that via rotatable storage rollers is attached to both sides of the table for a patient. The shape of the belt is controlled by a frame and guiding pins that are displacable along the frame, said guiding pins being connected to the belt in two points. By activating a crank the belt may be wound up on the rollers and hence pressed against the abdomen of the patient . The belt may be returned to an inactive position by spring action from the guiding pins. Said device has a relatively complicated structure by the combination of a belt and a guiding frame. Further, the crank should bring both storage rollers to rotate simultaneously. This device is also stationary and constitutes a permanent part of the table for a patient. 2 Objects and Features of the Invention

A primary object of the present invention is to present a compression device of the type mentioned above, said device being mobile, i.e. it is possible, with reasonably simple manipulations, to attach the device to one longitudinal edge of an examination table.

A further object of the device according to the present invention is that said device may easily be activated manually by the operator when he/she is in close connection with the device.

At least the primary object of the compression device according to the present invention is realised by means of a device that has been given the features defined in the appending independent claim. Preferred embodiments of the invention are defined in the dependent claims.

Brief Description of the Drawings

Below embodiments of the invention will be described, reference being made to the accompanying drawings, where :

Figure 1 shows a side view of the compression device according to the present invention; Figure 2 shows a detail of the fastening means that is incorporated in the compression device; Figure 3 shows a partly sectioned view of the compression device from the side where the device is equipped with a crank; Figure 4 shows a top view of the displacement mechanism of the compression device according to the present invention, said displacement mechanism being in a first mode of operation, Figure 5 shows a detail of a portion of the displacement mechanism; Figure 6 shows a top view of the displacement mechanism according to figure 4, said displacement mechanism being in a second mode of operation; Figure 7 shows a schematic side view of an alternative embodiment of the compression device according to 3 the present invention, especially an alternative attachment to the table is shown; Figure 8 shows a top view of an alternative displacement mechanism of the compression means; and Figures 9-11 show details of different operative modes of a manually activated means included in the displacement mechanism.

Detailed Description of Preferred Embodiments of the Invention In figure 1 the compression device according to the present invention is shown, said device comprising a frame 1 that at one end is provided with a fastening means 3, by which the compression device may be fixed to one longitudinal edge of an examination table 5. The compression device according to the invention also comprises a crank 7 and a covering compression plate 9, said crank 7 and said compression plate 9 being provided on opposite sides of the frame 1. The compression plate 9 is preferably manufactured from a plastic material that is reinforced by graphite yarn, said material being permeable for x-rays without contrast. The crank 7 and the compression plate 9 are both connected to a displacement mechanism that is provided inside the frame 1, said displacement mechanism 9 will be described more in detail below. The fastening means 3, shown in figure 2, comprises an L-shaped profile 10 and a movable jaw 11 that may be brought to move in the longitudinal direction of the frame 1 by activation of a screw 12. In connection with the mounting of the compression device on a longitudinal edge of the examination table 5 the jaw 11 is displaced in a direction away from the portion of the L-shaped profile 10 that is intended to abut the upper side of the examination table 5. By this arrangement the compression device may be provided on one longitudinal edge of the examinations table 5, and then the jaw 11 of the fastening means 3, by rotation of the screw 12 in appropriate direction, may be brought to abutment of the lower side of the examination table 5. By suitable tightening of the screw 12 a firm fastening of the compression device to said longitudinal edge of the examination table 5 is achieved. The downward bent edge of the examination table, see figure 1, is received between the jaw 11 and a support plate 13 of the fastening means 3.

As is evident from figures 3, 4 and 6 the frame 1 is box shaped, a displacement mechanism being provided inside said frame 1. Said displacement mechanism comprises a gear rack 14 that has a certain extension along in principle the entire longitudinal direction of the frame 1. The gear rack 14 extends parallel to the longitudinal direction of the frame 1 and is attached to end portions 15 of the frame 1. A box shaped carriage 16 is displacable along the gear rack 14, said carriage 16 being guided relative to the walls of the box shaped frame 1 via on one hand a number of ball bearings 17, in the disclosed embodiment eight ball bearings 17, and on the other hand a number of sliding rails 18, in the disclosed embodiment two sliding rails 18, see figures 4 and 6. In the carriage 16 a gear pinion 19 is rotatably mounted, said gear pinion 19 being drivingly connected to the crank 7 via a shaft 8 that is rotatably journalled in two opposite walls of the carriage 16. That the gear pinion 19 and the crank 7 are drivingly connected means that the gear pinion 19 rotates when the crank 7 is rotated.

The compression plate 9 is also attached to the carriage 16, via a holder 20 and a spigot 21 or the like, in such away that said compression plate 9 has an extension in principle perpendicular to the longitudinal direction of the frame 1. The compression plate 9 is pivotally attached to the carriage 16 since the spigot 21 is pivoted relatively to the carriage 16. The compression plate 9 is also detachable from the carriage 16 by having the spigot 21 removed from the carriage 16.

The frame 1 has a first slot 22 on the side where the crank 7 is attached and the frame 1 has a second slot 23 on the side where the compression plate 9 is attached, said two slots 22, 23 being essentially parallel to each other and having an extension in the longitudinal direction of the frame 1. The connection between the crank 7 and the gear pinion 19 runs in the slot 22, said connection constituting a shaft 8, while the spigot 21 runs in the slot 23. As is evident from figures 4-6 the gear pinion 19 is provided with a first step shaped end surface 24 on the side facing towards the crank 7, see figure 5. In a corresponding way, a blocking means 25 is provided with a second step shaped end surface 26 on the side facing towards the gear pinion 19, see figure 5, said blocking means 25 cooperating with the gear pinion 19. A pressure spring 27 strives to displace the gear pinion 19 in a direction towards the blocking means 25, said pressure spring 27 being provided on the shaft and abutting against a wall of the carriage 16.

The compression device according to the present invention functions in the following way. As is illustrated in figure 1 a patient 28 is placed on his back on the examination table 5. Normally, the patient 28 is first placed on the examination table 5 and then, as described above, the compression device according to the invention is mounted on one longitudinal edge of the examination table 5. Alternatively, it is also feasible that the compression plate 9 is removed from the frame 1, said frame 1 already being mounted on the examination table 5 when the patient 28 is placed on said examination table 5. Then the compression plate 9 is connected, via the spigot 21, to the carriage 16 of the frame 1.

When the patient 28 is placed on the examination table 5 and the compression device is mounted on said table 5 an adjustment for an x-ray photograph is initially effected and then the compression plate 9 is displaced downwards, see the arrow 29 in figure 1. This is effected by rotating the crank 7 in a certain direction and hence also the gear pinion 19 will rotate in the same direction. The gear pinion 19 and the carriage 16 will be displaced downwards along the gear rack 14 while the shaft 8 moves downwards in the first slot 22 and the spigot 21 moves downwards in the second slot 23.

As is indicated in figure 5, for a certain direction of rotation, said direction being symbolised by the arrow 30 in figure 5, the first end surface 24 of the gear pinion 19, said end surface 24 being provided with steps, will move relatively the second end surface 26, said second end surface 26 being provided with steps. The first end surface 24, said end surface 24 being provided with steps, will then perform a climbing movement relative to the second end surface 26, said end surface 26 being provided with steps. Said "climbing" will be interrupted regularly when a step is terminated. As is evident from figure 5 the axial surfaces of each end surface cooperate, said end surfaces being provided with steps. This prevents a rotation of the gear pinion 19 in a direction opposite the direction of the arrow 30 since the pressure spring 27 urges the gear pinion 19 against the blocking means 25. The end surfaces 24, 26, said end surfaces being provided with steps, form together a non-return stop that maintains the compression plate 9 at the attained level when said compression plate 9 is displaced in a direction towards the patient 28, i.e. effects compression. When the compression plate 9, by rotation of the crank

7, has been displaced in a direction towards the patient 28 until the desired compression rate has been achieved, then the displacement downwards of the compression plate 9 is interrupted and an individual x-ray photograph is taken. In order to interrupt the compression in preparation for the next x-ray photograph the crank 7 is pushed, against the action of a spring 27, in the direction of the arrow 31, see figure 6. By this action the function of the non-return stop is disengaged and the crank 7 may be rotated in a direction that makes the compression plate 9 to be displaced upwards in a direction away from the patient 28, i.e. the gear pinion 19 and the carriage 16 are displaced upwards along the gear rack 14 while the shaft 8 moves upwards in the first slot 22 and the spigot 21 moves upwards in the second slot 23. When the compression plate 9 has been removed a sufficient distance from the patient 28, the entire adjustment and compression process may be repeated cyclically, if required, in order to take another individual x-ray photograph. When the last adjustment and compression process, including the shooting of an x-ray photograph, has been terminated the entire compression device according to the present invention is removed from the examination table 5 or only the compression plate 9 is removed from the frame 1. The patient 28 may now 7 leave the explanation table 5 and the x-ray examination is finished.

In this connection it should be pointed out that when the patient is on the examination table 5 it is possible to alternate between x-ray photographs without compression and x-ray photographs using compression.

In the embodiment, disclosed in figure 7, of the compression device according to the present invention reference is especially made to be fastening of said device to the examination table 5' . As is evident from figure 7, said examination table 5' being equipped with a profile 6' along at least one longitudinal edge, said profile 6' having a T-slot 32'. The fastening means 3', shown in figure 7, comprises a T-shaped fastening element 33' that is rotatably connected to an externally threaded shaft 34', said shaft 34' being received in a threaded hole 35' of a plate 36' that is included in the fastening means 3' . Said plate 36' is attached, by means of screws 37', to the frame 1' of the compression device according to figure 7. A lever 38' is provided at the free end of the shaft 34', said lever 38' bringing the externally threaded shaft 34' to rotate and hence provide an internal fastening function, relative to the profile 6', between the fastening element 33' and the plate 36' . In connection with mounting of the compression device according to figure 7 in the profile 6' the T-shaped fastening element 33' is inserted into the T-slot 32' from an end side of the examination table 5' . When the desired position along the examination table 5' has been achieved the compression device is fastened via the fastening means 3' described above. This structural design also makes it easy to displace the compression device along the examination table 5', e.g. to the foot end of the examination table 5', by loosening the fastening means 3', e.g. when a patient is laying down on or raising from the examination table 5' . A covering compression plate 9', schematically shown in figure 7, is convertible between two positions, one of said positions being dash dotted in figure 7. The unbroken position in figure 7 is the normal position that is used for most patients. There may be a need to use the dash dotted position under certain circumstances, this means that the convertibility enables the device to effect compression within a large vertical area. Further the dash dotted position constitutes an out of the way parking position for the compression plate 9' .

The displacement mechanism, shown in figures 8-11, is provided inside a frame 1' that includes a box shaped casing 39', said casing 39' being equipped with a first internal guiding 40' and a second internal guiding 41' . When the displacement mechanism is activated a carriage 16' of the displacement mechanism is displaced along said guidings 40' and 41'.

The displacement mechanism comprises a stationary gear rack 14' and a gear pinion 19' that "climbs" the gear rack 14' . The gear pinion 19' is freely rotatably journalled on a shaft 44' of the displacement mechanism. On the same shaft 44' a ratchet wheel 45' is fixed, e.g. by means of a key joint, and a control handle 7' is freely rotatably journalled on said shaft 44' . A driving means 46', see figures 9-11, is pivotally journalled on said control handle 7', said driving means 46' having a pointed portion 47' that cooperates with the teeth of the ratchet wheel 45'. The detail shown in figures 9-11 represents the displacable carriage 16' .

As is evident from figures 9-11 also a pivotable pawl 48' is arranged to cooperate with the ratchet wheel 45', said pawl 48' being actuated by a pressure spring 49' . The function of this pawl 48' will be described more in detail in connection with the description below of the function of the displacement mechanism. The displacement mechanism also comprises a friction clutch 50', reference being made to figure 8, said friction clutch 50' having such a structural design that a first portion 51' of the friction clutch 50' is rotatably fixed relative to the shaft 44' but axially displacable, to a limited extent, from the actuation of a cup spring 52'. The spring force of said cup spring is adjustable by means of a nut 53' that is received on the shaft 44' by means of a thread. The friction clutch 50' also includes a second portion 54' that is integrated with the gear pinion 19' and thus freely rotatable relative to the shaft 44'. In order to transfer the rotational motion of the first portion 51' to the second portion 54' a number of balls 55' are provided, said balls 55' being received in recesses in the first and second portion 51' and 54' respectively.

The compression plate 9' , schematically shown in figure

8, is connected to the movable portion of the displacement mechanism, i.e. the carriage 16' that is displaced in the guidings 40' and 41'. The displacement mechanism described above functions in the following way. When the control handle 7', the ratchet wheel 45' and the pawl 48' are in the position shown in figure

9, i.e. both the pointed portion 47' of the driving means 46' and the pawl 48' are in engagement with the ratchet wheel 45', the compression plate 9' is locked against displacement upwards. In order to effect displacement of the compression plate 9' downwards, i.e. in direction from the viewer in figure 8, the control handle 7' is displaced in direction of the first arrow 56' in figure 10. The ratchet wheel 45' will then, by actuation from the driving means 46', rotate in direction of the second arrow 57' and said shaft 44' will rotate in the same direction. The first portion 51' of the friction clutch 50', said the first portion 51' being fixed on the shaft 44', will then rotate with the shaft 44' and by actuation from the spring 52' and the balls 55' the second portion of the friction clutch 50', and also the gear pinion 19' , will be driven. This means that the gear pinion 19' climbs downwards on the stationary gear rack 14', i.e. the compression plate 9' is displaced in direction towards the patient. The pawl 48' engages the ratchet wheel 45' as soon as the rotation of the ratchet wheel 45', in direction of the arrow 57', terminates. Thereby it is prevented that the compression plate 9' is displaced upwards when a new grip is effected by means of the control handle 7' . If the counteracting force increases, e.g. when the compression plate 9' comes into contact with the patient, the friction clutch 50' guarantees that a too high pressure, from the compression plate 9', is not exerted on the patient. If the counteracting force upon the compression plate 9' exceeds a predetermined value, the balls 55' and the axial force, generated by the spring 52', will not be able to drive the second portion 54' but the balls 55' will slide out of their recesses in the second portion 54' due to the fact that the first portion 51' is displaced to the left in figure 8, against actuation from the spring 52'. A repeated displacement of the control handle 7' in direction of the arrow 56' in figure 10 only brings the first portion 51' of the friction clutch 50' to be rotated while the second portion 54' is not driven.

When the pressure that the compression plates 9' exerts on the patient is to be interrupted, the control handle 7' is displaced in direction of the arrow 58' to the position shown in figure 11. In that position a mutual actuation of the driving means 46' and the pawl 48' is effected. This means that on one hand the driving means 46' is displaced to a position where the pointed portion 47' no longer engages the ratchet wheel 45' and on the other hand the pawl 48' is displaced, against the action from the pressure spring 49', to a position where the pawl 48' no longer engages the ratchet wheel 45'. Thereby, the compression plate 9' is released and may be displaced upwards in direction from the patient . It is possible to imagine that the compression device includes an incorporated pressure medium cylinder or a mechanical spring (not shown) that facilitates the displacement upwards of the compression plate 9' .

Feasible Modifications of the Invention

The fastening means 3; 3' according to the embodiments described above is adapted to the type of examination table 5; 5' that is shown above, i.e. tables having a special design of the longitudinal edges of the table 5; 5'. However, the compression device according to the present invention is in no way restricted to be used only in connection with examination tables of the type that is shown above and therefore it is possible, within the scope of the invention, too modify the fastening means in order to make it fit for different types of examination tables. In order to further improve the anchoring of the compression device to the examination table it may be mentioned, in exemplifying and non-restricting purpose, that the mechanical fastening may be completed by a vacuum that is generated between the fastening means and the examination table, said vacuum may be effected by means of a manual or motor driven vacuum pump. It is also feasible that the fastening to the examination table of the compression device according to the present invention is effected by means of a vacuum only.

The non-return stop mechanism described above may of course be designed in alternative ways without leaving the concept of the present invention. It is possible to imagine a mechanism that locks in both directions of displacement of the compression plate. Thereby, it is prevented that the compression plate unintentionally is falling down on the patient when he/she is on the examination table. As regards the embodiment according to figures 7-11 the pawl 48' and the spring 49' are normally so dimensioned relative to each other that no spontaneous displacement downwards occurs of the compression plate 9' .

In the embodiment shown in figure 7 the frame 1' is located on the side of the plate 36' that faces towards the examination table 5'. However, under certain conditions it may be preferable to have the frame located completely outside the examination table 5', i.e. in the shown embodiment on the side of the plate 36' that faces away from the examination table 5'. A reason for this alternative location of the frame is that in such a case the frame does not interfere with the mattress on the examination table 5', this may be experienced as troublesome, especially when the compression device is displaced along the examination table.

The friction clutch 50', described above in connection with figures 8-11, does only constitute a possible variant within the scope of the invention. However, it has turned out empirically that some type of mechanism is desirable, said mechanism guaranteeing that the compression plate 9; 9' does not exert a too high pressure on the patient.