JPH08112277A - X-ray CT system - Google Patents

Abstract

(57) [Summary] [Objective] A desired CR image of a plurality of regions of the same subject is captured in a short time. [Structure] An X-ray tube 25 and an X-ray detector 26, which are rotated so as to face each other, are attached to the opening 23 of the gantry 2, and the subject M is moved horizontally by the top plate 12 so that the opening 23 of the gantry 2 is moved.
It is inserted and removed. From the setting panel 3, a plurality of imaging regions of the same subject M and the arrangement angle of the X-ray tube 25 for each imaging region are set. According to the setting data, the control unit 5 irradiates an X-ray from the arrangement angle of the X-ray tube 25 in the first imaging region to illuminate the image with the X-ray, and then follows the CR image capturing of the imaging region with the next image. The CR image of the image pickup region is imaged by irradiating X-rays from the arrangement angle of the X-ray tube 25 in the image pickup region, and thereafter, similarly, the CR images of all the set image pickup regions are picked up by a series of operations. The obtained CR image is displayed on the monitor 6, and the operator makes a slice plan by observing it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT apparatus, and in particular, a CR (Computed Radiograph) for making a slice plan when a tomographic image is taken by the X-ray CT apparatus.
y, also called "scout view").

[0002]

2. Description of the Related Art An X-ray CT apparatus of this type comprises a gantry, a bed and the like. The gantry is provided with a cylindrical opening for inserting a subject. An X-ray tube and an X-ray detector are attached to the opening so as to face each other. The X-ray tube and the X-ray detector are configured to rotate in the circumferential direction of the opening while maintaining the facing state. On the other hand, in the bed, a top plate on which the subject is placed is mounted horizontally movable on the upper part of a vertically movable base fixed to the floor near the gantry. Insert into and remove from the gantry opening.

To capture a tomographic image by such an X-ray CT apparatus, the subject is placed on a top plate, the height of the subject is adjusted, and the top plate is moved horizontally to make the subject gantry. The position of the object to be imaged, which is inserted into the opening of the
The X-ray tube and the X-ray detector are rotated while the X-ray tube and the X-ray detector are positioned at the center of the imaging position, and the X-ray tube and the X-ray detector are rotated while irradiating the X-ray from the X-ray tube. This is performed by collecting line transmission data and reconstructing a tomographic image based on the collected data.

By the way, the imaging position for picking up the above-mentioned tomographic image is decided by the operator (doctor) by making a slice plan based on the CR image obtained prior to the imaging of the tomographic image.

Conventionally, the CR image is picked up as follows. That is, the X-ray tube is arranged at a predetermined position (for example, above the subject on the top plate), and one end side of a predetermined imaging region (for example, the head, the abdomen, or the whole body) is referred to as the X-ray tube. The top plate is moved so as to be located at the center of imaging by the X-ray detector, and X-rays are radiated from an X-ray tube arranged at a predetermined position, and the position within the imaging area located at the center of imaging is imaged. The top plate is moved so as to displace the area from one end side to the other end side, and the CR of the imaging area is moved.
Take an image.

The obtained CR image is displayed on a monitor, for example. The surgeon observes the CR image displayed on the monitor,
A slice plan for specifying the imaging position of the tomographic image (the position of the affected area for which detailed diagnosis is to be performed by imaging the tomographic image) is made.

The image pickup area for picking up a CR image is set by a technician (an operator who operates a CR image pickup operation or the like). Further, the arranging position of the X-ray tube is also set by the technician, but this arranging position is generally set at a position where it is easy to make a slice plan for the imaging region. For example, when the head is used as an imaging region, generally, a slice plan of the head is prepared based on a CR image obtained by arranging an X-ray tube on the side of the subject and irradiating X-rays from the X-ray tube. And again
When the region from the chest to the abdomen is used as the imaging region, C obtained by arranging the X-ray tube above the subject is generally used.
Based on the R image, a slice plan for the imaging area is prepared. Therefore, the technician sets the arrangement position of the X-ray tube according to the set imaging area.

[0008]

However, the prior art having such a structure has the following problems. For example, subjects (patients) with diseases at multiple locations
However, in order to examine each disease in detail, it is necessary to capture CR images of a region including each disease and determine the imaging position of the tomographic image based on each CR image.

In such a case, if the X-ray tube is arranged at the same position when capturing the CR image in each region, for example, the whole body may be set as the image capturing region and the CR image may be captured. As for the subject having the affected area in the head and in the area from the chest to the abdomen, as described above,
Since the arrangement position of the X-ray tube at the time of capturing the R image is different, in the CR image capturing method in which the whole body is set as the image capturing region,
The desired CR image cannot be obtained.

Therefore, in such a case, conventionally, a CR image of the head is first taken to make a slice plan of the head, and then C of the region from the chest to the abdomen is taken.
The slice plan of each area is established by the procedure of capturing the R image and establishing the slice plan of the area.

However, in such a conventional procedure, the CR image must be picked up in two steps,
There is a problem that the examination time becomes long, the subject is distressed, and the technician's CR image capturing work is complicated.

The present invention has been made in view of such circumstances, and it is possible to take desired CR images of a plurality of regions of the same subject in a short time, and a technician at that time It is an object of the present invention to provide an X-ray CT apparatus capable of reducing the work described above.

[0013]

The present invention has the following configuration to achieve the above object. That is, according to the present invention, (a) a cylindrical opening for inserting a subject is provided, and the X is attached so as to face the opening.
A gantry that rotates the X-ray detector and the X-ray detector in the circumferential direction of the opening while maintaining the facing state, and (b) the subject is placed, and the subject is placed in the opening of the gantry. A bed having a top plate to be inserted and removed; (c) a plurality of imaging regions of the same subject; and an arrangement angle of the X-ray tube with respect to each of the imaging regions (the X-ray tube for the subject on the top plate). (Arrangement position), and (d) the top plate is moved so that one end side of the set first imaging region is positioned at the center of imaging by the X-ray tube and the X-ray detector. At the same time, the X-ray tube is rotated so as to be arranged at the set arrangement angle of the X-ray tube in the imaging region,
While irradiating X-rays from the X-ray tube arranged at the arrangement angle, the position within the first imaging region located at the imaging center is displaced from one end side to the other end side of the imaging region. The plate is moved to capture a CR (scout view) image of the first imaging region, and then the top plate is moved so that one end side of the set next imaging region is located at the imaging center. At the same time, the X-ray tube is rotated so as to be arranged at the set arrangement angle of the X-ray tube in the image pickup area, and the next image pickup is performed by the same operation as the CR image pickup of the first image pickup area. And a control means for controlling the CR images of the regions to be captured, and thereafter, the CR images of the respective set imaging regions to be imaged while irradiating X-rays from the arrangement angle of the X-ray tube in the respective imaging regions. (E) obtained by being controlled by the control means Is obtained and a display means for displaying the CR image of the imaging region.

[0014]

The operation of the present invention is as follows. The engineer is
The setting means sets a plurality of imaging regions of the subject and the arrangement angle of the X-ray tube with respect to each imaging region (position of the X-ray tube with respect to the subject on the top plate).

The control means controls the CR of each set imaging area.
Images (each CR image is obtained by arranging the X-ray tube at an arrangement angle of the X-ray tube set for each imaging region and irradiating X-rays from the X-ray tube) are continuously captured.

That is, the control means positions one end side of the first set imaging region (for example, the head) (the top end of the imaging region) at the imaging center of the X-ray tube and the X-ray detector. The tabletop on which the subject is placed is moved in such a manner that the X-ray tube is arranged at the set imaging area (head) at the placement angle (the state where the X-ray tube is located on the side of the subject). Rotate to position the x-ray tube. At this time, since the X-ray detector is rotated while maintaining the state of facing the X-ray tube, it is arranged on the opposite side of the X-ray tube with the subject in between. Then, while irradiating X-rays from the X-ray tube arranged at the arrangement angle, the first imaging region (head) located at the imaging center.
The top plate is moved so as to displace the position of from the one end side (the end portion on the parietal side) of the imaging area (head) to the other end side (the end portion on the neck side), and the imaging area (head) The transmitted X-ray data from one direction is detected by the X-ray detector to obtain a CR image of the set first imaging region (head).

Next, from the state where the other end side (neck side end) of the first image pickup area (head) is located at the image pickup center,
The top plate is moved so that one end side (end portion on the head side) of the next set imaging area (for example, the area from the chest to the abdomen) is positioned at the imaging center, and the set imaging area ( The X-ray tube is rotated so as to be arranged at an X-ray tube arrangement angle (a region from the chest to the abdomen) (a state in which the X-ray tube is positioned above the subject), and the first imaging region (head)
The CR image of the imaging region (the region from the chest to the abdomen) is captured by the same operation as the capturing of the CR image of. Thereafter, similarly, a CR image of each set imaging region is imaged while irradiating an X-ray from the arrangement angle of the X-ray tube in each imaging region.

Each CR image thus picked up is displayed on the display means. The operator makes a slice plan for each imaging region based on each CR image displayed on the display means.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an X-ray CT according to an embodiment of the present invention.
FIG. 2 is a front view showing a schematic configuration of the entire apparatus, FIG. 2 is a view showing a positional relationship between a subject on a top plate and a gantry (X-ray tube, X-ray detector), and FIG. 3 is a tilt of the gantry. FIG. 4 is a front view showing a state, and FIG. 4 is a diagram for explaining a configuration of a light projector for aligning a specific portion of the subject with an imaging center.

The apparatus of this embodiment comprises a bed 1, a gantry 2, a setting panel 3, an image processing section 4, a control section 5, monitors 6 and 7.
And the like.

The bed 1 is fixed to the floor and is mounted on an upper portion of a base 11 which is moved up and down by an actuator (not shown).
A top plate 12 on which the subject M is placed is provided so as to be horizontally movable. The top plate 12 is horizontally moved in the left-right direction in FIG. 1 by rotation of the motor 13 in the forward and reverse directions, and the subject M on the top plate 12 can be inserted into and removed from the opening 23 of the gantry 2. . Rotation of the motor 13, that is, the top plate 1
The horizontal movement of 2 is controlled by the control unit 5 as will be described later, but can also be performed (manually) by an operator operating a button 14 provided on the base 11. It should be noted that the raising and lowering of the base 11 can also be performed by the button 14. Further, for example, the data PD for recognizing the movement amount of the top plate 12 obtained by detecting the number of rotations of the motor 13 by a rotary encoder (not shown) or the like.
Are provided to the control unit 5.

The gantry 2 is provided on the gantry base 21 fixed to the floor so as to be tiltable as shown in FIG. The inclination of the gantry 2 is performed by the rotation of the motor 22 in the forward and reverse directions, and the rotation of the motor 22 is controlled by the control unit 5.

Further, the gantry 2 is provided with a cylindrical opening 23 for inserting the subject M, and a ring-shaped rotary frame 24 is rotatably provided inside the gantry 2. An X-ray tube 25 and an X-ray detector 26 are attached to the rotary frame 24.
And are installed facing each other. Rotating frame 24
Is rotated in the forward and reverse directions around the central axis CJ of the opening 23 by the motor 27, whereby the X-ray tube 25 and the X-ray detector 26 are maintained facing each other, and the opening 23 is opened.
It is configured to be rotated in the circumferential direction. Motor 2
The forward and reverse rotations of 7 are controlled by the control unit 5 as described later. Further, information about the arrangement angle of the X-ray tube 25 (the arrangement position of the X-ray tube 25 with respect to the subject M on the top plate 12) is recognized by an angle sensor or the like (not shown) for detecting the rotation angle of the rotating frame 24. The data KD for the above is detected and provided to the control unit 5.

The start and stop of the X-ray irradiation from the X-ray tube 25 is controlled by the control unit 5 via a high voltage generator (not shown). Further, on the X-ray XR irradiation side of the X-ray tube 25, a collimator 28 for adjusting the spread angle α of the X-ray XR irradiated from the X-ray tube 25 and the irradiation X-ray thickness t is attached. There is. Further, a data acquisition unit (DAS) not shown is connected to the X-ray detector 26, the transmitted X-ray data (collection data) detected by the X-ray detector 26 is acquired by the DAS, and the image processing unit 4 is operated. Is configured to give.

In the opening 23 of the gantry 1, as shown in FIG. 4A (a sectional view taken along the line AA of FIG. 2), X
A light projector 29 that irradiates the light ML in a direction coinciding with the imaging center SC of the radiation tube 25 and the X-ray detector 26 is provided. Then, as shown in FIG. 4B, while inserting the subject M into the opening 23 of the gantry 2, the technician observes the light ML emitted from the projector 29 to the subject M, and the technician determines that the subject M The specific part of is aligned with the imaging center SC.

The setting board 3 has a plurality of imaging regions of the same subject M, the arrangement angles of the X-ray tubes 25 with respect to the respective imaging regions (positions of the X-ray tubes 25 with respect to the subject M on the top plate 12), The imaging position of the tomographic image determined by the slice plan based on the obtained CR image is set, and the CR
This is for setting an instruction to start capturing an image or a tomographic image. The setting board 3 corresponds to the setting means in this invention.

The image processing section 4 is controlled by the control section 5,
The CR image and the tomographic image are reconstructed based on the collected data supplied from the DAS.

The control section 5 controls each section based on the data set from the setting panel 3 and the like, as will be described later, to control the CR.
An image or a tomographic image is taken, and the images reconstructed by the image processing unit 4 are displayed on the monitors 6 and 7. The control section 5 corresponds to the control means in the present invention, and is composed of, for example, a microcomputer.

The obtained CR image is displayed on the monitor 6 as described later, while the obtained tomographic image is displayed on the monitor 7 as described later.

Next, the operation of picking up a CR image by the embodiment apparatus having the above-mentioned configuration will be described with reference to the flow chart shown in FIG.

First, the operator waits for an instruction to start capturing a CR image from the operation panel 3 (step S).
However, before 1) the CR image capturing start instruction is given, the technician performs the following initial work.

First, the imaging regions at a plurality of locations of the subject M,
The arrangement angle of the X-ray tube 25 with respect to each imaging region is set from the setting panel 3. It is assumed that, for example, as shown in FIG. 6, two areas are set as the imaging area, that is, the head (imaging area SR1) and the area from the chest to the abdomen (imaging area SR2). The setting of the imaging region is performed by, for example, the length L1 between the top end P1 and the neck end P2 of the imaging region SR1, the neck end P2 of the imaging region SR1, and the imaging region SR2. This is performed by setting a length L2 between the head-side end P3 and a length L3 between the head-side end P3 and the foot-side end P4 of the imaging region SR2.

Further, the X-ray tube 25 for the imaging region SR1
Is set to “90 °” (side of the subject M on the top plate 12 as shown by the chain double-dashed line in FIG. 2), and the arrangement angle of the X-ray tube 25 with respect to the imaging region SR2 is “0. ° "(Fig. 2
As shown by the solid line in FIG. In this setting method, for example, the state in which the X-ray tube 25 is arranged above the subject M on the top plate 12 shown by the solid line in FIG. 2 is “0 °”, and the clockwise direction in FIG. 2 is the positive direction. The absolute angle is set from "0 °" to "359 °".

Then, the technician places the subject M on the top plate 12 so that the head thereof faces the gantry 1 side, and the button 1
4 is operated to move the base 11 up and down, and the body axis J of the subject M (see FIG. 1) and the center axis CJ of the opening 23 of the gantry 2 are moved.
(See FIG. 1), the height of the subject M is adjusted, and the light is emitted from the projector 29.
The button 14 is operated to horizontally move the top plate 12 to the left in FIG. 1, and the subject M is inserted into the opening 23 of the gantry 2. Then, it is observed whether or not the light from the light projector 29 is applied to one end side (the end P1 of the imaging region SR1 in the above setting) of the first imaging region (the above setting is the imaging region SR1). When the edge P1 of the imaging region SR1 is illuminated,
The button 14 is operated to stop the horizontal movement of the top plate 12.
At this time, the end P1 of the imaging region SR1 is located at the imaging center SC of the X-ray tube 25 and the X-ray detector 26.

When the work up to this point is completed, the technician gives an instruction from the operation panel 3 to start capturing a CR image. As a result, the control unit 5 starts the operation after step S2 in FIG. Each data previously set by the engineer from the setting panel 3 is given to the control unit 5.

Steps S3 to S5 are operations for picking up a CR image of the i-th image pickup region, and in this embodiment, the set image pickup regions are sequentially and sequentially picked up in the order closer to the gantry 2 (step S3). S2, S6, S7). In the above setting, i = 1 (imaging region SR1), i = 2
The operations of steps S3 to S5 are repeated for (imaging region SR2).

In step S3, the controller 5 controls the motor 13
Drive control the one end side of the i-th imaging region
5 and the top plate 12 is moved so as to be positioned at the imaging center SC by the X-ray detector 26. In the case of i = 1, that is, in the case of the imaging area SR1 which is the first imaging area, as a result of the initial work by the technician described above, the end P1 of the imaging area SR1 is already located at the imaging center SC, so this step S3 Then, the top plate 12 is not moved. Also, i = 2,
That is, in the case of the imaging area SR2 which is the next imaging area,
As will be described later, since the end portion P2 of the image pickup region SR1 is located at the image pickup center SC when the image pickup of the CR image of the image pickup region SR1 with i = 1 is completed, the image pickup region S is changed from that state.
The top plate 12 is moved leftward in FIG. 1 by L2 so that the end P3 of R2 is located at the imaging center SC.

The control of the movement amount of the top plate 12 is performed based on the data PD given to the control unit 5 for recognizing the movement amount of the top plate 12. For example, when the number of revolutions of the motor 13 is given as the data PD, the amount of movement of the top plate 12 per one revolution of the motor 13 is known, so (the number of revolutions of the motor 13) × (one of the motors 13) The amount of movement of the top plate 12 can be known from the amount of movement of the top plate 12 per rotation.

In step S4, the controller 5 causes the motor 27 to
Is controlled to rotate the rotary frame 24 so that the X-ray tube 25 is arranged at the arrangement angle of the X-ray tube 25 in the i-th imaging region. In the above setting, the CR of the imaging region SR1 with i = 1
In the case of capturing an image, the disposition angle of the X-ray tube 25 is disposed at “90 °”, and in the case of capturing a CR image of the imaging region SR2 where i = 2, the disposition angle of the X-ray tube 25 is set to “0 °”. Will be placed.

The rotation control of the rotary frame 24, that is,
The controller 5 recognizes the arrangement angle (arrangement position) of the X-ray tube 25.
Is performed based on the data KD for recognizing the information regarding the arrangement angle of the X-ray tube 25 (the arrangement position of the X-ray tube 25 with respect to the subject M on the top plate 12) given to the. For example, the data KD is output every time the rotation frame 24 rotates by 1 ° and a signal kd1 that detects that the X-ray tube 25 is positioned above the subject M on the top plate 12 shown by the solid line in FIG. When it is configured with the pulse signal kd2 that is generated, the time when kd1 is obtained is recognized as “0 °”, and the arrangement angle (arrangement position) of the X-ray tube is recognized by counting the number of pulses of kd2. You can The state in which the X-ray tube 25 is arranged above the subject M on the top plate 12 shown by the solid line in FIG.
“0 °” to “3” with the clockwise direction in FIG. 2 as the positive direction.
In order to recognize the arrangement angle of the X-ray tube 25 with the absolute angle of “59 °”, if the rotation direction of the rotary frame 24 (the forward and reverse directions of the rotation of the motor 27) is added to the recognition based on the above kd1 and kd2. Good. That is, for example, from the state in which the signal of kd1 is given (the state in which the X-ray tube 25 is located at “0 °” in absolute angle), the rotary frame 24 is rotated rightward in FIG.
If the count value of the pulse signal of kd2 becomes 90, it can be known that the X-ray tube 25 is located at "90 °" in absolute angle.

The X-ray detector 26 is arranged opposite to the X-ray tube 25 with the subject M sandwiched by the rotation of the rotary frame 24.

Note that either of the above steps S3 and S4 may be performed first, or they may be operated simultaneously.

In step S5, the controller 5 controls the X-ray tube 25
X-ray exposure is started and the motor 13 is driven and controlled to irradiate X-rays from the X-ray tube 25 arranged in step S4, and the i-th imaging region located at the imaging center SC The top plate 12 is moved so as to displace the position from one end side to the other end side of the imaging region, and a CR image of the i-th imaging region is captured. In the case of the imaging region SR1 with i = 1, the top plate 12 is moved from the state where the end P1 of the imaging region SR1 is located at the imaging center SC to the state where the end P2 of the imaging region SR1 is located at the imaging center SC. L1 only, Fig. 1
To the left, and in the case of the imaging area SR2 of i = 2,
From the state where the end P3 of the imaging region SR2 is located at the imaging center SC, the end P4 of the imaging region SR2 is located at the imaging center SC.
The top plate 12 is moved by L3 in the leftward direction in FIG. The control of the movement amount of the top plate 12 is also performed in the same manner as in step S3. When the top plate 12 is moved by a predetermined amount (L1 when i = 1, L3 when i = 2), the X-ray exposure is stopped. The CR image of the i-th imaging region is reconstructed by the image processing unit 4.

As a result, the CR images of the imaging regions at a plurality of positions of the same subject M, which are different in the arrangement angle (arrangement position) of the X-ray tube 25, do not have to be taken twice as in the conventional example. , Can be performed by a series of operations.

In the above example, the case of picking up the CR images of the two image pickup areas is shown, but the CR image of the three or more image pickup areas can be similarly picked up. For example, as shown in FIG. 7, three imaging regions SR1 and SR
2. When capturing the CR image of SR3, it is performed as follows. Note that SR1 and SR2 are the same as the imaging area (including the arrangement angle of the X-ray tube 25) in FIG.

First, in setting the image pickup region SR3, the length L4 between the foot side end P4 of the image pickup region SR2 and the head side end P5 of the image pickup region SR3, and the head side of the image pickup region SR3. The length L5 between the end P5 and the foot-side end P6 of the imaging region SR3 is set. Further, since the slice plan based on the CR image of the imaging region SR3 is performed by observing the curved state of the spine, the arrangement angle of the X-ray tube 25 is “90 °” (see FIG. 2) as in the imaging region SR1. As shown by the chain double-dashed line, it is set on the side of the subject M on the top plate 12).

In the operation shown in FIG. 5, after the CR images of the image pickup areas SR1 and SR2 are picked up by the same operation as the above example, the steps relating to the image pickup operation of the CR image of the image pickup area SR3 of i = 3. In S3, when the image pickup operation of the CR image of the image pickup region SR of i = 2 is completed, the end portion P of the image pickup region SR2 is
Since 4 is located at the imaging center SC, in order to position the end P5 of the imaging region SR3 of i = 3 at the imaging center SC, the motor 13 is rotated in the reverse direction and the top plate 12 is moved by L4.
It is moved to the right in FIG. 1, and in step S4, the rotary frame 24 is rotated so that the arrangement angle of the X-ray tube 25 is set to “90 °” in absolute angle. While irradiating X-rays from the X-ray tube 25 arranged on the side of the subject M, the motor 13 is rotated in the forward direction to move the top plate 12 to L5.
Only, CR in the imaging region SR3 by moving to the left in FIG.
Take an image.

Returning to FIG. 5, each CR image obtained is displayed on the monitor 6 in step S8. This display method is
For example, as shown in FIG. 8A, each CR image reduced to 1/4 may be divided into two and displayed on the monitor 6, or as shown in FIG. Alternatively, one CR image may be displayed on the monitor 6, and the CR image to be displayed on the monitor 6 may be switched according to the operator's instruction from the setting panel 3.

Further, for example, if the obtained CR images are three (or four) images as in the setting of FIG. 7, then FIG.
As shown in, each CR image reduced to 1/4 may be divided into four and displayed on the monitor 2. Further, if the obtained CR images are five or more, each CR image reduced to 1/4 is displayed on the monitor 2 in four divisions, and the display of the four divisions is switched. Alternatively, each CR image reduced to 1/16 may be divided into 16 and displayed on the monitor 2.

Next, the operator displays the CR displayed on the monitor 6.
The image is observed, a slice plan is prepared, the position at which the tomographic image is captured is determined, and set from the setting panel 3. At this time,
As shown in FIGS. 8A and 8C, if the CR images are divided and displayed, the imaging position of the tomographic image can be determined while simultaneously observing the obtained CR images. It is convenient to make a slice plan while grasping the situation.

Next, the technician sets the start of the tomographic image setting on the setting board 3
Is controlled by the control unit 5, and tomographic images at the imaging positions determined by the operator are sequentially captured. The outline of this operation is as follows.
The top plate 12 is moved so as to be positioned at C, the gantry 2 is tilted if necessary, and the rotary frame 24 is rotated while irradiating X-rays from the X-ray tube 25, and X in the circumferential direction of the imaging position. The line transmission data is collected, and the image processing unit 4 reconstructs a tomographic image at the imaging position based on the collected data.
Next, the top plate 12 is moved so that the second image pickup position is located at the image pickup center SC, and a tomographic image of the image pickup position is obtained in the same manner as above. After that, the same operation is repeated, and tomographic images at the imaging positions determined by the operator are continuously and sequentially imaged.

Here, an example of the imaging position of the tomographic image determined by the slice plan is shown in FIG. 9 (a). FIG.
(A) shows the monitor 6 after the imaging position of the tomographic image is set.
In the figure, reference numerals SL1 to SL4 (in this example, four imaging positions are set) are lines indicating the imaging positions of the determined tomographic images. In addition, depending on the setting from the setting board 3, the lines SL1 to SL4 are
It is displayed in an overlapping manner on the CR image of the monitor 6. Further, FIG. 9B shows the relationship between the determined imaging position of the tomographic image and the actual subject M.

The length L11 in the figure can be calculated as follows. Both ends P1 and P2 of the imaging region SR1
The length of the interval is L1 and the number of pixels of the CR image in the interval is known. If this number of pixels is G1, (L1 / G1)
Then, the actual length of one pixel (gi1) is obtained. Therefore,
C between the end P1 of the imaging region SR1 and the imaging position SL1
L11 is obtained by multiplying the number of pixels on the R image (denoted as G11) by the gl1. Similarly, L21 is the length L3 between both ends P3 and P4 of the imaging region SR2.
By dividing by the number of pixels (G2) between both ends P3 and P4 of the CR image of No. 2, the actual length gl2 of one pixel is obtained, and the real length gl2
It can be obtained by multiplying the number of pixels on the CR image between the end P3 of R2 and the imaging position SL3. In addition, other L12,
L13, L22, and L23 can be calculated similarly.

Therefore, the CR image pickup operation (for example,
When the tomographic image is continuously captured from the state in which the image capturing operation for the setting of FIG. 6 is completed, the last image capturing area (S
Since the end portion P4 of the image pickup region SR2 is located at the image pickup center SC due to the completion of the CR image pickup of R2), the top plate 12
By moving L23 to the right in FIG.
L4 is located at the imaging center SC and a tomographic image is taken,
Next, the top plate 12 is moved by L22 in the right direction in FIG. 1, the imaging position SL3 is located at the imaging center SC, and a tomographic image is taken. Then, replace the top plate 12 with (L21 + L2 + L
13) only, move it to the right in FIG.
2 is located at the imaging center SC to capture a tomographic image, the top plate 12 is moved by L12 in the right direction in FIG. 1, and the imaging position SL1 is located at the imaging center SC to capture a tomographic image. .

Further, the subject M is placed in the opening 23 of the gantry 2.
When starting from the action of inserting into the
4 is operated to move the top plate 12 horizontally, and the light from the projector 29 causes the end portion P1 of the imaging region SR1 of the subject M on the crown side.
If the top plate 12 is stopped when it is irradiated with, and then the start of the imaging of the tomographic image is instructed, the control unit 5 sets the top plate 12 to the L level.
11 is moved to the left in FIG.
Is positioned at the imaging center SC to capture a tomographic image, and then the top plate 12 is moved by L12 in the left direction in FIG. 1 to position the imaging position SL2 at the imaging center SC to capture a tomographic image. After that, the tomographic images at the image capturing positions SL3 and SL4 are continuously captured in the same manner.

The lines SL1 and SL2 indicating the image pickup position in the image pickup region SR1 are inclined with respect to the body axis J. In this case, the gantry 2 is inclined rightward in FIG. Set the imaging center SC to the lines SL1 and SL2
The tomographic image may be taken in accordance with the above. This gantry 2
The control section 5 drives and controls the motor 22 to incline.

The CR of the image pickup area SR3 set in FIG.
In the image, as shown in FIG. 10, when the imaging position of the tomographic image is determined along the curve of the spine R as SL5 to SL7, the gantry is changed according to the inclination state of each line SL5 to SL7 with respect to the body axis J. 2 may be tilted in the left-right direction in FIG. 3 to capture each tomographic image.

The obtained tomographic image is displayed on the monitor 7. This display method may be configured such that one of the tomographic images obtained is displayed on the monitor 7 and display switching of each tomographic image is performed from the setting panel 3, or the obtained tomographic images are reduced to 1 / 4 or 1
It may be reduced to / 16 and displayed in four or 16 divisions. Further, each time the tomographic image at each imaging position is captured, the color of the lines SL1 to SL4 displayed on the monitor 6 may be changed to display the tomographic image capturing status. At this time, if each CR image is divided and displayed on the monitor 6 and the obtained CR image is displayed on the monitor 6 at the same time, it is convenient because it is possible to grasp the entire imaging situation of the tomographic image.

Further, in FIG. 9 above, four imaging positions are set, but even when three or less imaging positions or five or more imaging positions are set, the tomographic image is obtained by the same operation as described above. Can be imaged.

By the way, the projector 29 of the above-mentioned embodiment
Is configured to align a specific portion of the subject M (one end P1 of the first imaging region SR1) with the imaging center SC. For example, as shown in FIG. There is also a gantry 2 provided on the insertion opening side of the subject M in the opening 23 of the gantry 2 (a position closer to the bed 1 side than the imaging center SC). In the case of such a configuration, the technician manually moves the top plate 12,
The light from the light projector 29 is applied to the first end portion P of the first imaging region SR1.
1 is irradiated, the movement of the top plate 12 is stopped, and if an instruction to start capturing a CR image in that state is given, the control unit 5
In the operation of S3 in the flowchart of FIG. 5 related to the first capturing of the CR image of the imaging region SR1, the top plate 12 is set to L3.
Only 0 is moved to the left in FIG. In addition,
This L30 is the length between the image pickup center SC and the light projector 29 and is known. Further, the light from the projector 29 causes the image pickup area S
After aligning one end P1 of R1, the shooting position S
When capturing a tomographic image of L1, the control unit 5 performs (L3
If the top plate 12 is moved leftward in FIG. 1 by 0 + L11), the imaging position SL1 can be located at the imaging center SC.

Further, as shown in FIG. 11B, when the projectors 29 are individually provided outside the gantry 2, the movement of the top plate 12 of the L30 in the case of FIG. If the length L40 between the image pickup center SC and the light projector 29 is changed, the CR image or the like is picked up in the above-described embodiment or FIG.
This can be performed in the same manner as the modified example of.

[0062]

As is apparent from the above description, according to the present invention, the CR images to be imaged in which the arrangement angles of the X-ray tubes are arbitrarily set for the imaging regions at a plurality of places of the same subject are obtained. Since it is configured so that continuous imaging can be performed, compared with the conventional example, the inspection time can be shortened, the pain of the subject can be reduced, and the CR image capturing work of the technician can be simplified, and the burden on the technician can be reduced. You can

[Brief description of drawings]

FIG. 1 is a front view showing the overall schematic configuration of an X-ray CT apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a positional relationship between a subject on a top plate and a gantry (X-ray tube, X-ray detector).

FIG. 3 is a front view showing an inclined state of a gantry.

FIG. 4 is a diagram for explaining a configuration of a light projector for aligning a specific portion of a subject with an imaging center.

FIG. 5 is a flowchart showing a CR image capturing operation by the apparatus of the embodiment.

FIG. 6 is a diagram showing an example of a set imaging area.

FIG. 7 is a diagram showing another example of a set imaging area.

FIG. 8 is a diagram for explaining a method of displaying the obtained CR image on a monitor.

FIG. 9 is a diagram showing an example of a slice plan.

FIG. 10 is a diagram showing another example of a slice plan.

FIG. 11 is a diagram for explaining a modified example of the light projector.

[Explanation of symbols] 1 ... Bed 2 ... Gantry 3 ... Setting panel 5 ... Control unit 6, 7 ... Monitor 12 ... Top plate 23 ... Gantry opening 25 ... X-ray tube 26 ... X-ray detector M ... Subject SR1 ~ SR3 ... Imaging area SC ... Imaging center

Claims (1)

[Claims] 1. (a) A cylindrical opening for inserting a subject is provided, and an X-ray tube and an X-ray detector, which are attached so as to face the opening, are provided in a circumferential direction of the opening. A gantry that rotates while maintaining the facing state; (b) a bed on which a subject is placed and a top plate that inserts and removes the subject into and from the opening of the gantry; and (c) the same subject. Setting means for setting a plurality of imaging regions and an arrangement angle of the X-ray tube with respect to each of the imaging regions (arrangement position of the X-ray tube with respect to the subject on the top plate); and (d) the setting. The top plate is moved so that one end side of the first imaging area is located at the imaging center of the X-ray tube and the X-ray detector, and the arrangement angle of the X-ray tube in the set imaging area is set. Rotate the X-ray tube so that While irradiating the X-ray from the X-ray tube, the top plate is moved so as to displace the position in the first imaging region located at the imaging center from one end side to the other end side of the imaging region. , A CR (scout view) image of the first imaging region is taken, and then the top plate is moved so that one end side of the set next imaging region is located at the imaging center, and the setting is performed. Further, the X-ray tube is rotated so as to be arranged at the arrangement angle of the X-ray tube in the image pickup region, and the CR image of the next image pickup region is obtained by the same operation as that of the CR image of the first image pickup region. And (e) the control means for controlling the imaging of the CR image of each of the set imaging regions while irradiating the X-ray from the arrangement angle of the X-ray tube in each of the imaging regions. The CR image of each imaging region obtained by being controlled by the control means is X-ray CT apparatus characterized by comprising a Shimesuru display means.