JPH07209427A - Sciltillation camera - Google Patents

Abstract

PURPOSE:To improve the operability for the positioning between a top plate and a detector by providing a mechanism for moving the top plate for placing a subject interlockingly with a detector situated on the lower side of the top plate in a scintillation camera having two detectors arranged thereon opposite to each other. CONSTITUTION:A scintillation camera has a top plate 1, radiation detectors 2, 2b vertically arranged opposite to each other, a motor 4 for driving the top plate 1, a motor 7 for driving the detectors 2a, 2b, a first position detector 11 for detecting the position of the detector, a second position detector 12 for detecting the position of the top plate 1, and an interlocking motor controller 13 for driving the top plate 1 and the lower detector 2b interlockingly to each other. The position of the top plate 1 with the detectors 2a, 2b is monitored while vertically moving the two detectors 2a, 2b so as to interlockingly drive the top plate 1 and the lower detector 2b just before the contact of the top plate 1 with the lower detector 2b, whereby the detectors 2a, 2b and the top plate 1 are mutually positioned. The frequency of the button operation required for the positioning is reduced, and operability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scintillation camera, and particularly to operability in positioning a bed top plate on which a subject is placed and a radiation detector for detecting radiation emitted from the subject. And a scintillation camera with improved

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing a configuration of an example of a conventional two-detector type scintillation camera. As shown in FIG. 4, in this scintillation camera, two radiation detectors 32a are provided above and below, with a top plate 31 on which a subject is placed sandwiched.
32b are provided, and these radiation detectors 32 are provided.
The detector drive mechanism 33 moves the a and 32b in the vertical direction so that the distance between the two detectors can be freely changed.

In this scintillation camera, one drive mechanism 3 is provided for each of the two radiation detectors 32a and 32b.
3 is provided, and when one of the detectors is moved upward, the other detector is moved downward so that the distance between the two detectors can be adjusted. . The detector driving mechanism 33 is connected to a detector driving motor 34, and the motor 34 is drive-controlled by a motor controller 35.

On the other hand, the top plate 31 is configured to move in the vertical direction by the top plate drive mechanism 36. The top driving mechanism 36 is driven by a top driving motor 37 under the control of a motor controller 38.

The detector drive motor controller 35 and the top plate drive motor controller 38 are connected to an operation switch 39, and the operator operates the switch 39 to operate the upper and lower detectors 32a and 32b. , The top plate 31 is positioned.

In such a scintillation camera,
When the subject is imaged, it is preferable to keep the vertical distance between the subject and the radiation detector equal and to keep the distance between the subject and the detector as close as possible. Therefore,
The operator operates the switch 39 to move the top plate 31 and the detectors 32a and 32b so that the distance between the detector and the subject is reduced. First, by the detector drive mechanism 33, until just before the upper detector 32a and the upper surface of the subject placed on the top plate 31 come into contact with each other, or the lower surface of the top plate 31 comes into contact with the lower detector 32b. The upper and lower detectors 32a and 32b are moved until just before. At this time, the operator always confirms the distance between the upper detector 32a and the upper surface of the subject and the distance between the lower detector 32b and the lower surface of the top plate 31, and the two radiation detectors. It is necessary to discriminate which one comes into contact with the upper surface of the subject or the lower surface of the top plate 31 first, and carefully perform the operation.

When the lower detector 32b contacts the lower surface of the top plate 31 and there is a gap between the upper detector 32a and the upper surface of the subject, the top drive mechanism 38 is operated. The plate 31 is moved upward for adjustment, and conversely, the upper detector 32a and the upper surface of the subject come into contact with each other, and the lower detector 132b and the top plate 3 are contacted.
If there is a gap between the lower surface and the lower surface of 1, the top plate 31 is moved downward so that the vertical distance between the subject and the vertical detector is the same.

As described above, in the conventional scintillation camera shown in FIG. 4, the top plate 31 is moved up and down to perform the positioning so that the distance between the subject and the upper and lower detectors 32a and 32b becomes the same. It is very difficult to do this operation by visual inspection. Therefore, when positioning the top plate and the radiation detector, the operation of moving the upper and lower detectors 32a and 32b and the top plate 31 must be repeated several times, which causes a problem of poor operability.

FIG. 5 is a diagram showing the configuration of another example of a conventional two-detector type scintillation camera. In the scintillation camera shown in FIG. 5, independent detectors 32a and 32b are provided with independent drive mechanisms 33a and 33b, respectively, and drive motors 34a and 34b and a drive controller 35 are provided.
a and 35b are also provided respectively. In the scintillation camera thus configured, the operability of positioning the radiation detector and the top plate is generally better than that of the scintillation camera shown in FIG. That is, the positioning can be performed by two operations of using the drive mechanism 33a to bring the upper detector 32a closer to the subject and using the drive mechanism 33b to bring the lower detector 32b closer to the lower surface of the top plate 31. .

However, the upper and lower detectors 32a, 32
Since an independent drive mechanism is required for each of b, the device becomes large. In particular, since each radiation detector weighs about 400 kg, a motor of considerably high output is required to move it. When the two detectors are provided with independent drive mechanisms, two motors are required, which causes a problem that the manufacturing cost increases in addition to the increase in size of the device.

[0011]

As described above, in the conventional scintillation camera of the type in which two radiation detectors are driven by one driving mechanism as shown in FIG. 4, the top plate and the radiation detector are used. However, there is a problem in that the operation for positioning is complicated and the operability is poor. As shown in FIG. 5, in the type in which two radiation detectors each have an independent drive mechanism, The operability is excellent, but there is a problem that the device becomes large and the manufacturing cost becomes high.

The present invention solves such a problem and is excellent in operability when positioning the top plate and the radiation detector,
Moreover, it is an object of the present invention to provide a small and inexpensive scintillation camera.

[0013]

The above object is to provide a top plate on which a subject is placed, two radiation detectors arranged so as to face each other with the top plate sandwiched therebetween, and detection of these two units. Drive means for moving the container to change the distance between the two, second drive means for moving the top plate, and a radiation detector located below the top plate and the top plate interlocked with each other. This is achieved by a scintillation camera including a third drive control unit that is driven by the above method.

Further, for the above-mentioned purpose, the scintillation camera further comprises a first position detecting means for detecting the position of the radiation detector, a second position detecting means for detecting the position of the top plate, and a second position detecting means for detecting the position of the top plate. Position monitoring means for monitoring the outputs of the first and second position detecting means, and the position monitoring means recognizes that the distance between the top plate and the lower radiation detector has reached a predetermined value. In addition, the top plate and the lower radiation detector are interlocked by the third driving means to position the top plate and the radiation detector.

[0015]

As described above, the scintillation camera of the present invention is equipped with the third drive means for driving the top plate and the lower detector in conjunction with each other, and the distance between the top plate and the lower detector is increased. When it comes close to the desired position, the top plate and the lower detector are interlocked by the third drive means to move the top plate and the lower detector simultaneously in the same direction and at the same speed. To do so. In this way, the third drive means keeps the distance between the two constant and further narrows the distance between the two detectors, so that the top plate and the detectors can be easily positioned.

Further, in the preferred scintillation camera of the present invention, further, first position detecting means for detecting the position of the radiation detector, second position detecting means for detecting the position of the top plate, and these first and second position detecting means. A means for monitoring the outputs of the first and second position detecting means is provided, and the distance between the top plate and the lower detector is monitored by this monitoring means, and this distance approaches and reaches a predetermined value. At this time, the operability can be further enhanced by performing positioning by interlocking the top plate and the lower detector by using the third drive means.

[0017]

Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a diagram showing the configuration of an embodiment of the scintillation camera of the present invention. In FIG. 1, a top plate 1, upper and lower radiation detectors 2a and 2b, a detector drive mechanism 3, a detector drive motor 4, a detector drive motor controller 5, a top drive mechanism 6, and a top drive motor. 7, the top plate driving motor controller 8 and the operation switch 9 are the same as those of the conventional scintillation camera shown in FIG. 4, and therefore the description of these components will be omitted.

The scintillation camera of this embodiment has, in addition to the above-mentioned structure, a first position detector 11 for detecting the positions of the radiation detectors 2a and 2b and a second position detector for detecting the position of the top 1. The detector 12, the interlocking motor controller 13 that interlocks the top plate and the lower detector 2b to drive, and the top drive motor while monitoring the outputs of the first and second position detectors 11 and 12. A switching control device 14 for switching the connection of 7 to the motor controller 13 is provided.

In the switching control device 14, the top plate drive motor 7 is connected to the motor controller 8 and the interlocking motor controller 1
Switch means is provided for switching between 3 and 3.
In this switch means, the top plate drive motor 7 is connected to the motor controller 8 side when the positioning is started. Further, the output of the second position detector 12 that detects the position of the top plate 1 and the output of the first position detector 11 that detects the positions of the detectors 2a and 2b are input to the switching control device 14. And here, the top plate 14 and its radiation detectors 2a, 2b
And monitor the position.

Positioning of the top plate 1 and the detectors 2a and 2b is performed as follows. First, the radiation detectors 2a and 2b
Is moved up and down to narrow the gap between the top plate 1 and the lower detector 2b. The switching control device 14 monitors the distance between the tabletop 1 and the lower detector 2b, and when it recognizes that this distance is below a predetermined value, it outputs a control output to the tabletop drive motor 7 to the motor. From the controller 8 to the interlocking motor controller 13
Switch to.

The output of the first position detector 11 and the output of the second position detector 12 are also given to the interlocking motor controller 13, and after the switching is performed, the controller 1
In step 3, while controlling the positions of the lower detector 2b and the top plate 1, the drive motor 7 of the top plate 1 is controlled so that the top plate 1 tracks the operation of the detector 2b. In this way, while keeping the distance between the top plate 1 and the lower detector 2b constant, the distance between the upper and lower detectors 2a and 2b is shortened so that the detector and the top plate come to a desired position. adjust. Top plate 1 and lower detector 2
Since the distance from b is kept constant, adjustment can be easily performed.

FIG. 2 is a block diagram showing an example of the configuration of the interlocking motor controller 13. The position signal Rx of the lower detector 2b detected by the first position detector 11 is calculated by the calculator 13
The level is converted to the same format as the position signal Tx of the top plate 1 by a and becomes a signal Px. This level-converted signal Px becomes a target position signal for the vertical movement of the tabletop 1, and the controller 13 divides the signal Px and the position signal Tx of the tabletop 1 detected by the second position detector. The control output of the top plate driving motor 7 is changed so that the same level is obtained. The position signal Px of the lower detector 2b and the position signal Tx of the top 1 whose levels have been converted are subtracted by the subtractor 13b,
It becomes the deviation signal Dx. The deviation signal Dx is supplied to the amplifier circuit 13c.
And a signal multiplied by a gain kxp and an element obtained by integrating the signal Dx with time are kxi
The multiplied signal is obtained and these signals are added by the adder 13e to obtain the speed command signal Pu.

The position signal Tx of the top plate 1 is input to the subtractor 13b and also to the differentiating circuit 13f, where it is differentiated with respect to time and converted into the velocity signal Tv. The speed command signal Pu and the speed signal are subtracted by the subtracter 13g to become the speed deviation signal Dv, which is further multiplied by the gain kup by the amplifier 13h and input to the drive motor 7 of the top 1 as a control output. .

By configuring the interlocking motor controller 13 in this way and applying this control output to the top plate driving motor 7, the detector 2b and the top plate 1 can be moved together.

All the constituent parts of the motor controller 13 may be composed of analog elements, or part of them may be digitalized. Further, part or all of the digitized part can be replaced with arithmetic processing by a microprocessor.

FIG. 3 is a block diagram showing an example of a system in which almost all control elements of the motor controller 13 are processed by the microprocessor 20. The rotary motor 2 drives the detectors 2a and 2b, the drive motor 7 drives the top plate 1, and the rotary encoder 2
1, 22 are connected to each other, and the lower detector 2b and the top plate 1 are connected.
And position detection with.

These rotary encoders 21, 22
Are connected to counters 23 and 24, respectively, and the microprocessor 20 is connected to these counters 23 and 24.
The positions of the detector 2b and the top plate 1 are recognized by reading the value of. All arithmetic processing performed by the interlocking motor controller 13 shown in FIG. 2 is performed by the microprocessor 20. The calculation results (digital values) performed by the microprocessor 20 are input to the D / A converters 25 and 26 to be converted into analog values, and these signals are further amplified through the amplifiers 27 and 28 to drive the detector drive motor. 4 and the top plate drive motor 7 to control the drive speed of the detector 2b and the top plate 1.

As described above, in the scintillation camera of the present invention, the top plate 1 and the lower detector 2b are provided with the control means for controlling the drive in association with each other, and the detector 2a, which is performed before photographing the subject, Since the positioning of 2b and the top plate 1 can be performed by one button operation, the operability of positioning is significantly improved.

[0029]

As described above, according to the present invention, a scintillation camera having two detectors arranged to face each other and having one drive system for these two detectors is used as a top plate. By driving and controlling the detector and the detector in conjunction with each other, positioning of the subject and the detector is facilitated, and the operability of the scintillation camera can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an embodiment of a scintillation camera of the present invention.

FIG. 2 is a block diagram showing an example of the configuration of an interlocking motor controller that drives and controls the top plate and the detector in conjunction with each other in the scintillation camera of the present invention.

FIG. 3 is a block diagram showing an example of a configuration of a motor controller for interlocking the scintillation camera of the present invention.

FIG. 4 is a diagram showing an example of a configuration of a conventional scintillation camera.

FIG. 5 is a diagram showing another example of the configuration of a conventional scintillation camera.

[Explanation of symbols]

 1 Top Plate 2a, 2b Detector 4 Drive Motor 5 Motor Controller 7 Drive Motor 8 Motor Controller 11 Position Detector 12 Position Detector 13 Interlocking Motor Controller 14 Switching Control Device

Claims (2)

[Claims] 1. A top plate on which a subject is placed, two radiation detectors arranged so as to face each other with the top plate sandwiched between them, and these two detectors are moved so as to move between them. A first drive unit that changes the distance, a second drive unit that moves the top plate, and a third drive that interlocks and drives the radiation detector located below the top plate and the top plate. A scintillation camera, comprising: a control unit. 2. The scintillation camera according to claim 1, further comprising: first position detecting means for detecting the position of the radiation detector, and second position detecting means for detecting the position of the top plate. Position monitoring means for monitoring the outputs of the first and second position detecting means is provided, and the position monitoring means confirms that the distance between the top plate and the lower radiation detector has reached a predetermined value. When recognized, the scintillation camera, characterized in that the top plate and the radiation detector are positioned by interlocking the top plate and the lower radiation detector by the third driving means.