JP2525774B2 - Positioning device for CT device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a positioning apparatus for a radiation tomography apparatus that enables anyone to perform positioning easily.

(Prior Art) As one of the radiation tomography apparatuses, there is an apparatus called computerized tomography (hereinafter referred to as CT apparatus). This device is, for example, a fan beam X-ray FX that spreads in the shape of a flat fan as shown in FIG.
An X-ray source 1 for irradiating the X-rays in a pulsed manner and a radiation detector 2 formed by arranging a plurality of radiation detection cells D _{1 to} D _n for detecting the X-rays, facing each other through a subject 3. Further, the X-ray source 1 and the radiation detector 2 are rotationally moved in the same direction synchronously with each other about the subject 3 to collect X-ray absorption data in various directions of the cross section of the subject 3.

Then, after collecting sufficient data, this data is analyzed by an electronic computer, and X-rays for the respective positions of the subject tomographic plane are analyzed.
By calculating the linear absorptance and reconstructing the cross-section of the subject with a gradient corresponding to the absorptance, it is possible to analyze with a gradient of up to 4000 steps depending on the composition, so from soft tissue A clear tomographic image can be obtained up to the hard tissue.

In such a CT apparatus, first, it is necessary to set the tomographic plane of the patient's observation target site in the imaging region (in the region where the fan beam X-rays in all directions of the rotating fan beam X-rays overlap). However, it is difficult to accurately enter the shooting area because the shooting area is invisible.

Further, in order to obtain a better image, it is necessary to set the tomographic plane of the observation target site of the patient in the center of this region, but this is more difficult.

In particular, of the data collected by the detector, the data outside the tomographic plane is wasted. Therefore, the relative positions of the radiation source and the detector with respect to the subject are moved so that the imaging region is changed to the affected area (target area) tomographic plane. It is even more difficult if the width can be varied according to the size of.

In order to perform this positioning, conventionally, a projector for projecting a positioning spot across the photographing hole is provided on the front side surface of the gantry.

That is, as shown in FIG. 6, the CT apparatus has a mechanism for supporting the X-ray tube 1 and the detector 2 and rotating them around the tomographic plane of the subject, which is called a gantry including the housing. . The gantry 4 is provided with a photographing hole 4a for arranging a patient in the center, and an X-ray is formed through the photographing hole 4a.
The line tube 1 and the detector 2 face each other.

Therefore, the bed top 5 in the horizontal state is inserted into the imaging hole 4a to image the tomographic plane of the subject 3 on the bed top 5. However, when imaging a tilted cross section, The gantry itself will be tilted.

Therefore, in order to know how much the gantry is tilted with respect to the subject 3, the gantry is spotted in the direction parallel to the plane of the X-ray fan beam XR in the vicinity of the imaging hole 4a.
A light projector 6 for positioning light for projecting 6a is provided.

Therefore, during positioning, the bed top 5 is moved so that the target portion of the subject 3 on the bed top 5 is spotted by the projector 6.
After adjusting to the 6a position, the height of the bed top 5 is adjusted, and then the predetermined amount of the bed top 5 is sent to the gantry 4 side so that the target site is aligned with the imaging region. The thickness S of the fan beam XR becomes the slice thickness, and X-ray absorption data within this slice thickness S can be collected.

Since the slice thickness S is usually about several millimeters, the CT images for a plurality of cross sections are obtained by shifting the pitch by the slice thickness S and used for diagnosis.

Therefore, an image that can be used for diagnosis cannot be obtained unless the position is set correctly. Then, as a condition for correctly setting the position, it is possible to operate the bed top plate 5 so that the target portion fits within the imaging region. But,
The bed top 5 has operation buttons such as up, down, forward and backward,
You have to select and operate this appropriately, so if you are not familiar with it, it will be a difficult task. Therefore,
Positioning and imaging of the subject must rely on the hand of a person who is familiar with the operation of this CT device, and an unfamiliar person cannot image the target region satisfactorily.

(Problems to be Solved by the Invention) As described above, conventionally, when imaging a target region of a patient (subject) using a CT device, the target region should be placed within the imaging region of the CT device. It is necessary to set the sample,
The positioning work is very troublesome unless the person is accustomed to the fact that the shooting area is in a space that cannot be used for purpose. There is also one that automatically adjusts the height of the bed top so that the subject is located at the optimum position in the imaging region by detecting the size of the subject, for example, as shown in U.S. Pat.No. 4,558,458, but the slice position Must be decided manually,
The problem is not resolved.

By the way, in general, on holidays, Saturday afternoons, nights, etc., the staff who handles the CT device often returns home and is absent.

On the other hand, there is a situation in which it is not known when an emergency case will occur, and even if there is no staff who handles the CT device, it is desired to perform CT imaging for diagnosis.

However, as mentioned above, it is difficult to meet such a requirement in the present situation where it is difficult for an amateur to position the CT device.

By the way, in the case of emergency treatment, the place where you want to have a CT scan is usually good. This is because it suffices to grasp the condition of the affected part.

Therefore, the purpose of the present invention is to place the patient at a fixed position on the bed top of the CT apparatus and specify the desired site so that CT imaging of that site can be performed reliably.
Accordingly, it is to provide a positioning device for a CT device that enables even a person who is unfamiliar to handle the CT device.

[Structure of the Invention] (Means for Solving Problems) In order to achieve the above object, the present invention has the following structure. That is, the bed top plate with a mark indicating the position of the imaging target site in advance at a predetermined position on the tabletop, the imaging site selection switch provided corresponding to this mark, and the CT corresponding to this switch. An imaging area determining means for determining the size of the imaging area of the device, and a CT corresponding to the switch.
Selection means for selecting the top movement position and height position to the photographing position of the device, detection means for detecting the position of the top board, and comparison of the detection values of the detection means with reference to the selection position of the selection means. A control means for generating a control amount necessary for the detected value to reach the reference value and a drive means for adjusting the position of the top plate according to the control amount.

(Operation) In such a configuration, the operator first places the subject on the top plate so that the target portion of the subject matches the position of the mark attached to the corresponding position on the top plate, and then the operator Press the switch corresponding to the part. By this, the shooting area is selected, and
The top moving position and the height position of the CT device to the imaging position are selected by the selecting means, and the position of the top output from the detecting means is compared with the selected value as a reference value. Then, the control means generates a control amount necessary for the detected value to reach the reference value, and drives the driving means according to the control amount,
Adjust the position of the top plate.

As a result, the position that the top plate should reach is the position where the mark on the top plate coincides with the slice position of the CT device, and the position that the top plate should reach in the vertical direction is the bottom of the subject. The tabletop is automatically adjusted so that it is located at the bottom of the imaging area, so place the subject on the tabletop so that the target site is at the mark corresponding to the site on the tabletop. Then, just by selecting the positioning switch, the optimum size of the shooting area for shooting is selected and set,
In addition, the top plate is at a position where the mark position corresponding to the selection switch matches the slice position of the CT device, and the height is also at the bottom of the subject, so that the headrest and top plate are at the bottom of the imaging area. It is automatically set, and the target part is surely set within the imaging area.

Therefore, anyone can easily and surely perform imaging of the target site simply by arranging the subject such that the target site comes to the position of the mark corresponding to the site on the top plate.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of this device.
The drawing is a plan view showing the structure of the bed top part.

In this apparatus, the bed top 10 is constructed as shown in FIG. That is, in the figure, 10a is a bed,
A top plate portion 10b is provided above the bed 10a so as to be movable in the longitudinal direction. The bed part 10a can move the top plate part 10b up and down by a built-in drive mechanism. Further, in order to specify a place to place the subject on the top plate portion 10b, for example, "head", "lung", "liver" on the headrest portion 10c or the top plate.
Characters such as "" and the placement area shall be marked.

In FIG. 1, 11 is a positioning switch,
As shown in the figure, align with the above mark on the top plate, "head",
Push-button switch with letters such as "lung" and "liver" 11
There are a, 11b and 11c. Reference numeral 12 denotes an imaging area determination circuit. When any one of the push button switches 11a, 11b, 11c is selected and pressed, the imaging area determination circuit 12 selects an imaging area A or B corresponding to a region of the subject to be imaged. Decide which one to use (see FIG. 4).

For example, if the switch 11a called "head" is pressed, a small photographing area A suitable for photographing the head is selected. Which region is selected is predetermined.

Reference numeral 13a is an arrival position selection circuit for selecting the arrival position in the vertical direction of the top plate, and 13b is an arrival position selection circuit for selecting the arrival position of the top plate in the advance / retreat direction with respect to the gantry. All of these are to receive an input from the positioning switch 11 and an input from the imaging area determining circuit 12 and select a preset top-plate reaching position in the part selected by the switch 11.

14a is a comparison circuit for the top and bottom directions of the top, and 14b is a comparison circuit for the advance and retreat direction of the top with respect to the gantry, and the arrival position information is obtained from the corresponding arrival position selection circuits 13a and 13b, respectively. The detected position information from the corresponding position detectors 17a and 17b is compared to detect whether or not they match.

15a is a drive control circuit for the vertical direction of the tabletop, 15b is a drive control circuit for the forward and backward direction of the gantry of the tabletop, by the arrival position selection circuit 13a, 13b according to the output of the corresponding comparison circuit 14a, 14b respectively. The position of the tabletop should be moved until the determined position and height of the tabletop should be reached,
It controls the drive units 16a and 16b for the drive movement operation. That is, the drive unit of the top is driven and controlled until the current position and the position to be reached match. At this time, a sequencer 18 is provided to control the first vertical movement and then the horizontal movement (movement in the backward direction). The position detectors 17a and 17b are for detecting the current position of the top plate, and the position detector 17a detects the height position of the top plate, and the position detector 17b detects the position of the top plate in the forward / backward direction. .

As the position detectors 17a and 17b, a detector that outputs an absolute position, such as a potentiometer, is used.

The position that the bed top should reach is the position where the mark position on the bed top coincides with the slice position S of the CT apparatus.
Further, the position to be reached in the vertical direction of the bed top plate is determined so that the headrest and the bed top plate, which are the lowermost part of the subject, are located as shown in FIG. That is, as the CT device, the rotation center O of the X-ray tube 1 and the detector 2 is moved,
In the case of a shift type device in which the imaging area can be selected from A and B, a small imaging area A is selected when the head is selected, and a large imaging area B is selected when the lung or liver is selected. The rotation center O of the X-ray tube 1 and the detector 2 is moved so as to become the imaging area. Therefore, when the head is designated, the height is set so that the headrest 10c is placed at the lowest position of the photographing area A selected at that time. When a lung or a liver is designated, a large photographing area B is selected, and therefore the height is set so that the whole top plate is at the lowest position in the photographing area B.

 Next, the operation of the present apparatus having the above configuration will be described.

First, the operator places the subject on the top plate 10b so that the portion of the subject to be imaged is at the corresponding marking position. At this time, in the X-ray CT apparatus, the slice position of the subject is moved and a number of images are taken, so that the first slice is aligned with the mark.

After setting the subject, press the switch 11 for automatic positioning of the part to be imaged. As shown in FIG. 3, this switch 11 has a mark corresponding to the mark shown in FIG. When this switch is pressed, the imaging area determination circuit 12 determines the imaging area corresponding to the region of the subject to be imaged (see FIG. 4).

For example, if a switch called "head" is pressed, a small photographing area A suitable for photographing the head is selected. Which region is selected is predetermined. That is, the switches 11a to 11c shown in FIG.
Which one of B to choose is decided.

When the shooting area is determined, the arrival position selection circuit 13
The position and height of the top plate 10b to be reached are determined by a and 13b, and the drive unit 16 is operated until the current position and the position to reach reach the same.
a and 16b operate under the control of the drive control circuits 17a and 17b.
At this time, the sequencer 18 controls the vertical positioning of the top plate first and the horizontal positioning next. The current position is detected by the position detectors 17a and 17b, and the comparison circuits 14a and 14b compare the current position with the position to be reached and the driving units 16a and 16b continue to drive and move the top plate until they match. .

As the position detector, a detector that outputs an absolute position, for example, a potentiometer or the like is used, but even if you do not know the current position, you can know which way to move and if there is a sensor that can detect the position to reach .

In other words, in this case, when the subject is set on the tabletop, the initial state is always set, for example, the tabletop is lowered to the lowest position on the bed and is located farthest from the gantry, so the positioning operation is started. Sometimes it is only necessary to allow the top plate to move in the ascending direction and the gantry direction. Further, it is also possible to use only a detector whose state is switched at the position to reach. In this case, if there is a detector that outputs "0" if it has not arrived and "1" if it has arrived, it is possible to know whether to move it in the up-down direction or in the forward / backward direction with respect to the gantry, by looking at the state. The movement operation may be controlled to stop at the position where the output is switched.

As a result, the position that the top plate 10b should reach is the position where the mark on the top plate 10b coincides with the slice position S of the CT apparatus. Further, the top plate 10b should reach in the vertical direction such that the headrest and the top plate, which are the lowermost part of the subject, are as shown in FIG. Therefore, only by selecting the positioning switch 11, the size of the shooting area most suitable for shooting is selected, and the top plate has the mark position corresponding to the selection switch.
It is set so that the headrest and the top plate, which are at the position corresponding to the slice position S of the CT device and whose height is the bottom of the subject, are located at the bottom of the imaging region, and the target site is within the imaging region. Will definitely fit in.

As described above, the present invention attaches a mark indicating the arrangement position of the imaging target portion to a predetermined position on the top plate of the CT device in advance, and
A switch for selecting an imaging region is provided corresponding to this mark, imaging region determining means for determining the size of the imaging region of the CT device in correspondence with this switch, and an imaging position of the CT device in correspondence with the switch. Selecting means for selecting the top moving position and height position to the top, detecting means for detecting the position of the top, and comparing the detected values of the detecting means with the selected position of the selecting means as a reference, It comprises a control means for generating a control amount necessary to reach the reference value, and a drive means for adjusting the position of the top plate according to the control amount. Then, place the subject on the top plate so that the target part of the subject matches the position of the mark attached to the corresponding position on the top plate, and press the switch corresponding to that part to select the imaging area. The top moving position and the height position of the CT apparatus to the imaging position are selected by the selecting means, and the position of the top output from the detecting means is compared with the selected value as a reference value. Then, the control means generates a control amount necessary for the detected value to reach the reference value, and the driving means is driven according to the control amount to adjust the position of the top plate.

As a result, the position that the top plate should reach is the position where the mark on the top plate coincides with the slice position of the CT device, and the position that the top plate should reach in the vertical direction is the bottom of the subject. The tabletop is automatically adjusted so that it is located at the bottom of the imaging area, so place the subject on the tabletop so that the target site is at the mark corresponding to the site on the tabletop. Then, just by selecting the positioning switch, the optimum size of the shooting area for shooting is selected and set,
In addition, the top plate is at a position where the mark position corresponding to the selection switch matches the slice position of the CT device, and the height is also at the bottom of the subject, so that the headrest and top plate are at the bottom of the imaging area. It is automatically set, and the target part is surely set within the imaging area.

Therefore, anyone can easily and surely perform imaging of the target site simply by arranging the subject such that the target site comes to the position of the mark corresponding to the site on the top plate.

The present invention is not limited to the embodiments described above and shown in the drawings, but can be modified and implemented as appropriate without departing from the scope of the invention.

[Effects of the Invention] As described in detail above, according to the present invention, anyone can simply and surely arrange the subject so that the target site is located at the position of the mark corresponding to the site on the top plate. Features such as being able to perform imaging of the target site
A positioning device for a CT device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a plan view showing the structure of a bed top used in the present invention, FIG. 3 is a view showing an example of a positioning switch, and FIG. 4 is a selection. FIG. 5 is a diagram showing the positional relationship between the imaged region and the top plate or the headrest, and FIG. 5 is a diagram for explaining the principle of the CT device.
The figure shows the appearance. 10 …… Bed top, 10a …… Bed, 10b …… Top, 10
c …… Headrest, 11 …… Positioning switch, 11a, 1
1b, 11c ... push button switch, 12 ... shooting area determination circuit, 13a, 13b ... arrival position selection circuit, 14a, 14b ... comparison circuit, 15a, 15b ... drive control circuit, 16a, 16b ... drive Part, 17
a, 17b …… Position detector, 18 …… Sequencer.

Claims (1)

(57) [Claims] 1. A bed top plate in which a mark indicating the arrangement position of a region to be imaged is attached in advance to a predetermined position on the table, a switch for image region selection provided corresponding to this mark, and a switch corresponding to this switch. And an imaging area determination means for determining the size of the imaging area of the CT device, a selection means for selecting the top moving position and the height position of the CT device to the imaging position corresponding to the switch, Detection means for detecting the position, control means for comparing the detection value of the detection means with reference to the selected position of the selection means, and generating a control amount necessary for the detection value to reach the reference value, and this control amount A positioning device for a CT device, which comprises a driving means for adjusting the position of the top plate according to the above.