JPH0230721Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a contact detector, and more specifically, when the imaging device for film photography or fluoroscopy is brought into contact with a subject in a medical X-ray machine, it controls the movement stop of the imaging device. The present invention relates to contact detectors for X-ray equipment.

As shown in FIG. 1, a medical X-ray device, for example, an undertube fluoroscopic table for gastrointestinal system diagnosis, has a patient 3 placed on a table 2 and an X-ray tube device 1 positioned below them. , X-rays emitted from the X-ray tube device 1 pass through the table 2 and the patient 3,
An X-ray image is taken on a film 5 housed in a case 4.

In such an apparatus, the distance between the patient 3 and the film 5 is mentioned as a factor that affects the image quality, and it is known that the shorter the distance, the better the sharpness of the image obtained. For this reason, the case 4 containing the film 5 is electrically movable in the direction of arrow A, and the operator moves the case 4 according to the body shape and position of the patient 3, so that the case 4 is moved toward the patient 3. We are trying to take X-rays in close proximity. At this time, in order to prevent excessive pressure from being applied to the patient even if the patient 3 is hidden behind the inner width of the case 4 and the operator cannot see the distance between the patient 3 and the case 4, A contact detection device is provided on the contact surface. Conventionally, this contact detection device has provided a protective plate 8 with good X-ray transparency and rigidity in the X-ray irradiation field on the front of the case 4, engaged with the detection cover 7, and inserted the cover 7 into the guide pin 9. A dog 12 is attached to the detection cover 7, and a limit switch 11 is provided in the case 4, which closes when the detection cover 7 is pushed in the direction of the case 4. It consists of:
This is done by moving the case 4 in the direction of arrow A by remote control, and when the patient 3 and the case 4 come into contact, the limit switch 11 is activated via the protection plate 8 and the detection cover 7.
is activated to cut off the power to the electric motor that moves the case 4, so that the case 4 is always positioned closest to the patient 3.
to stop the system safely and reliably. Figure 2 shows a contact detection device in a device that takes X-ray movies for circulatory system diagnosis, and its configuration and operation are the same as those described above, except for case 4.
has been changed to an image intensifier tube 13.

In these conventional devices, the limit switch 11 is provided outside the case 4 or the image intensifier tube 13, so the detection cover 7
In the former case, there is a problem in that the detection cover covers or comes into contact with the patient's face, and in the latter case, there is a problem in that the image intensifier tube does not touch the patient's face when taking images from an oblique direction. There is a problem that it is difficult to approach
Another common problem is that since a space is required to move the protective plate 8, the distance between the patient 3 and the film 5 cannot be reduced to a certain dimension or less.

An object of the present invention is to provide a contact detector for a medical X-ray apparatus that can shorten the distance between an object to be inspected and a film in an X-ray apparatus, and can operate safely and reliably.

Embodiments of the contact detection device of the present invention will be described below with reference to FIGS. 3 to 7.

FIG. 3 shows a portion of an undertube X-ray device. The case 4 houses a film exchanger for the film 5, an image intensifier tube located above the film 5 for receiving an X-ray fluoroscopic image, and the like. This imaging device is brought into pressure contact with a patient 3 lying on a table 2, and fluoroscopy with an image intensifier tube and recording on a film 5 are performed.

The contact detector according to the present invention is installed on the lower surface of the case 4 of the imaging device that is in pressure contact with the patient. The detector 22 is disposed between the outer case 7 fitted to the case 4 and on both sides of the X-ray transmission window of the case 4. A cover 8 is placed between the detector 22 and the outer case 7 and covers the X-ray transparent window of the outer case.

When the case 4 is lowered as described above and the cover 8 comes into contact with the patient 3 and the force applied to the cover 8 exceeds a certain value, the detector 22 is activated to stop the lowering of the case 4 or to stop the case 4 from rising. I am making things happen.

Figures 4 and 5 show details of the detector. This detector includes a pair of sheet-shaped electrodes 16 placed on both sides of a pressure-sensitive resistance plate 15 made of a pressure-sensitive resistor so as to be able to make electrical contact with each other, and a pair of sheet-shaped electrodes 16 placed on both sides of these electrodes and integrated with the electrodes 16. It consists of a pair of insulating plates 17 laminated on top of each other. Pressure sensitive resistance plate 15
It is made of pressurized conductive rubber whose electrical resistance becomes extremely small when a force above a certain pressure is applied. Conventionally, there are detectors that use such pressurized conductive rubber, but because the conductive rubber is in close contact with the entire surface of the electrode plate, local deformation of the electrode plate due to impact etc. causes the detector to become continuously conductive. Something happened. In order to solve this problem, the present invention divides a sheet-shaped pressurized conductive rubber into a plurality of pieces, and in order to separate the plurality of pressure-sensitive resistance plates 15, an electrode is formed integrally with an insulating plate. Holding plates 19 made of an elastic material such as foamed synthetic resin are sandwiched between them as shown in FIG. 4, and the pressure-sensitive resistance plates 15 and holding plates 19 are arranged alternately in short strips. This holding plate 19 is connected to the pressure sensitive resistance plate 15 as shown in FIG.
The electrode 16 is formed to be somewhat thicker than the pressure sensitive resistor plate 15, thereby forming a gap between the electrode 16 and the pressure sensitive resistance plate 15. As described above, this holding plate 19 forms a gap between the electrode 16 and the pressure-sensitive resistance plate 15, and when the pressure is released, the contact between the electrode 16 and the pressure-sensitive resistance plate 15 is forcibly released. Even if the electrode plate 16 is locally deformed due to an impact or the like, the gap prevents the electrode 16 and the pressure-sensitive resistor plate 15 from becoming continuously electrically connected. The insulating plate 17 is made of, for example, a polyester resin sheet or film, and the electrodes are formed by depositing a good conductor such as copper on such a sheet or film.

The insulating plate 17 is arranged with the electrode 16 facing the pressure-sensitive resistance plate 15 side, and a protective plate 18 made of a rigid material
are arranged further outside, and the insulating plate 17, electrode 16, and holding plate 19 are brought into close contact with each other by these protective plates 18.

In such a contact detector, when force is applied to the protection plate 18, the electrical resistance value of the pressure-sensitive resistance plate 15, that is, the pressurized conductive rubber plate, decreases greatly, and the resistance of the relay etc. connected to it through the electrode 16 decreases greatly. The electric motor that moves the imaging device can be controlled through the switch.
In addition, since the pressure applied to the protection plate 18 is shared by the retainer plate 19, the elasticity of the retainer plate and the distance between the surface of the retainer plate and the surface of the pressurized conductive rubber plate, that is, the distance between the retainer plate and the pressure By selecting the difference in thickness of the conductive rubber plates, etc., it is possible to arbitrarily set the force that causes the electrical resistance value to change rapidly. In addition, this holding plate allows soft touch contact between the image device, that is, the contact detector surface, and the subject, which has the effect of alleviating pain to the subject. As shown in FIG. 6, the pressure sensitive resistance plate 15 is
A similar effect can be produced by hollowing out the holding plate 19 made of an elastic material such as the foamed synthetic resin and dispersing the pressure-sensitive resistance plates 15 therein. Note that also in this embodiment, the retaining plate 19
As in the previous embodiment, the pressure sensitive resistor plate 15 is slightly thicker than the pressure sensitive resistor plate 15, and is formed into a disk shape.

FIG. 7 shows an example of a control circuit for a drive circuit of a motor that moves an imaging device using the above-mentioned contact detection device. A switch constituted by a pressure-sensitive resistance plate 15 and an electrode 16 is connected in series with a relay coil 20. In this control circuit, a force is applied to the pressure-sensitive resistor plate 15, and when this force exceeds a certain value, the electrical resistance value of the pressure-sensitive resistor plate 15 rapidly decreases, the circuit closes, and the relay coil 20 is energized. The relay contacts are opened and closed to stop or reverse the motor that moves the video device. As shown in the drawings, a Zener diode 23 with an appropriate voltage rating may be inserted between the switch and the relay 20 to adjust the operation of the circuit according to the current flowing through the pressure sensitive resistor plate. .

As described above, the contact detector according to the present invention, which consists of the pressure-sensitive resistor plate 15 and the holding plate 19 arranged in a short strip shape, has an extremely thin thickness and can be housed only in the entire surface of the case 4. The distance between the film 5 and the subject 3 can be shortened, and even when the imaging device approaches the subject from an oblique direction, this can be done without being obstructed by a table or the like.

As shown in the embodiments described above, the contact detector of the present invention has a sensor that is arranged alternately with elastic retaining plates that are somewhat thicker than the pressure-sensitive resistor plates or in a dispersed manner by hollowing out the retaining plates. A pair of electrodes are arranged on both sides of the piezoresistive plate, and these sides are sandwiched between insulating plates, and further sandwiched between protective plates.The electric resistance value of the piezoresistive plate is determined by the force applied to the protective plate. The thickness of the film can be made extremely thin by rapidly changing the film thickness, so when used in an X-ray device, the distance between the subject in contact with the imaging device and the film can be extremely short, allowing for clear images. In addition to obtaining a clear image, the holding plate prevents continuous conduction from occurring due to local deformation of the electrode plate, making it easy to install in equipment as a safe and reliable contact detector. .

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory diagrams showing the configuration of a conventional contact detection device, respectively. 3 to 7 show an embodiment of the contact detector of the present invention, FIG. 3 is an explanatory diagram showing a state in which it is incorporated into an undertube type X-ray device, and FIG. 4 is an illustration of the detector. 5 is a cross-sectional view of the pressure-sensitive resistor plate and the retaining plate, and a plan view of these plates is shown along the line of FIG. 4.
FIG. 6 is a plan view showing another arrangement of the pressure sensitive resistance plate and the holding plate, and FIG. 7 is an electric circuit diagram for controlling the movement of the imaging device. 3... Subject, 4, 5... Imaging device, 15...
Pressure-sensitive resistance plate, 16... Electrode, 17... Insulating plate, 1
8...protection plate, 19...retention plate, 22...detector.

Claims (1)

[Scope of utility model registration request] An X-ray device provided at an end of a movable imaging device, comprising a detection means for detecting contact between the imaging device and a subject, and controlling a movement mechanism of the imaging device by an output signal from the detection means. In the contact detector for a device, the detection means includes a pair of insulating plates on which electrodes are formed by depositing a good conductor on one surface, a plurality of pressure-sensitive resistance plates arranged between opposing electrodes of the insulating plates, and A holder made of an elastic material thicker than the pressure-sensitive resistance plate, which is narrowly attached between the electrodes of the insulating plate so as to separate the pressure-sensitive resistance plates from each other and to form a gap between the electrode and the pressure-sensitive resistance plate. A contact detector for an X-ray apparatus, comprising: a plate; and a protection plate disposed outside the insulating plate and in close contact with the insulating plate.