JP2012075644A - X-ray image diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To capture an X-ray image through an easier operation by moving an area to be irradiated with an X ray by detecting a contrast medium in the X-ray image.SOLUTION: The X-ray image diagnostic device comprises: an X-ray tube configured to emit an X ray; a collimator configured to narrow the emitting range of the X ray by blocking at least part of the X ray; an imaging means configured to form an X-ray image by detecting the X ray whose emitting range has been narrowed by the collimator; a holding means configured to integrally hold the X-ray tube, collimator, and imaging means; a first moving means configured to move the collimator; a second moving means configured to move the holding means; and a control section configured to control the first and second moving means based on an moving instruction signal so as to move the holding means when the collimator moves.

Description

  The present invention relates to an X-ray diagnostic imaging apparatus that captures an X-ray image.

X-rays are irradiated to the subject, and X-rays transmitted through the subject are detected using an X-ray detector.
A so-called X-ray diagnostic imaging apparatus that captures a line image is becoming widespread. Such an X-ray diagnostic imaging apparatus is indispensable for today's medical treatment because it can observe the inside of a subject.

Currently, in order to observe the state of a blood vessel or the like of a subject, a method for photographing a contrast image has been developed in which a contrast medium is injected into a subject and photographing is performed. In imaging such a contrast image, when capturing a contrast image over a region wider than the imaging region, such as the lower limb of the subject, the X-ray irradiation region must be moved in accordance with the movement of the contrast agent flowing through the blood vessel. An invention is disclosed in which an X-ray irradiation region is moved in accordance with the movement of a contrast agent by moving a top plate or an X-ray tube and an X-ray detector on which a subject is placed according to a user input. ing.

JP 2009-291531 A

When a contrast image is captured using the above-described conventional X-ray image diagnostic apparatus, the user of the X-ray image diagnostic apparatus captures a contrast image in real time in the contrast agent injection region. The user visually observes the movement of the contrast agent appearing in the contrast image, and if the user recognizes that the contrast agent has moved to the end of the X-ray irradiation region, the user can check that the contrast agent is included in the X-ray irradiation region. Move the imaging system. The user captures a contrast image while repeating the monitoring of the contrast agent and the movement of the X-ray irradiation region.

By the way, a user who uses an X-ray diagnostic imaging apparatus is able to capture a contrast image in real time.
It is necessary to keep operating the operation switch for irradiating X-rays. While the user continues to operate the operation switch, if the user recognizes that the contrast medium has moved to the end of the X-ray irradiation area, the user must separately perform an operation to move the top plate. Performing a plurality of operations in parallel has a problem that the operation burden is large for the user.

This indication is made in order to solve such a subject, and it moves X-ray irradiation area by moving the holding means holding a collimator with movement of a collimator, and can carry out photography of an X-ray image more simply. Can be done.

In order to solve the above problems, in the present disclosure, an X-ray tube that irradiates X-rays, a collimator that blocks at least part of the X-rays and narrows the X-ray irradiation range, and the irradiation range is narrowed by the collimator. In addition, an imaging unit that detects the X-ray and generates an X-ray image, a holding unit that integrally holds the X-ray tube, the collimator, and the imaging unit, and a first moving unit that moves the collimator And the second moving means for moving the holding means, and the first and second to move the holding means with the collimator based on a movement instruction signal.
And a controller for controlling the moving means.

The block diagram which shows the structure of the X-ray-image diagnostic apparatus based on an embodiment. The figure which shows the relationship between the positional relationship of a collimator and an X-ray detector based on an embodiment, and an X-ray irradiation area | region. The figure which shows a mode that a X-ray irradiation area | region narrows according to the opening part of the collimator concerning an embodiment having narrowed. The figure which shows a mode that a X-ray irradiation area | region moves according to the movement of the arm based on embodiment. The figure which showed a mode that the contrast agent based on an embodiment appeared in an X-ray image. The figure which shows the mode of the subtraction image generation based on embodiment. The figure which shows the relationship between a collimator and an X-ray irradiation area | region based on an embodiment. The figure which shows the mode of the collimator immediately after contrast agent injection | pouring and contrast agent based on an embodiment, and the example of a screen display. The figure which shows the X-ray image image | photographed immediately after contrast agent injection | pouring which concerns on the embodiment, and the image profile in a monitoring area | region. The figure which shows the mode of the collimator when the time after contrast agent injection | pouring passes, and the contrast agent based on an embodiment, and the example of a screen display. The figure which shows the X-ray image image | photographed when the time after contrast agent injection | pouring passed according to the embodiment, and the image profile in a monitoring area | region. The figure which shows the mode of a collimator and a contrast agent when a contrast agent reaches | attains the monitoring area | region based on an embodiment, and a screen display example. The figure which shows the X-ray image image | photographed when the contrast agent arrived at the monitoring area | region based on the embodiment, and the image profile in a monitoring area | region. The figure which shows the mode of the collimator and contrast agent immediately after collimator movement based on an embodiment, and the example of a screen display. The figure which shows the X-ray image image | photographed immediately after the collimator movement based on the embodiment, and the image profile in a monitoring area | region. The figure which shows the mode of a collimator and a contrast agent when a contrast agent reaches | attains the X-ray detection area | region edge based on an embodiment, and a screen display example. The figure which shows the X-ray image image | photographed when the contrast agent arrived at the X-ray detection area | region edge based on the embodiment, and the image profile in a monitoring area | region. The figure which shows the mode of the collimator and contrast agent immediately after arm movement based on an embodiment, and the example of a screen display. The flowchart which shows the process which monitors a contrast agent and moves an arm and a holding means based on embodiment. The figure which shows the example of a setting of the monitoring area | region based on an embodiment. The figure which shows the operation | movement at the time of narrowing the opening part of the collimator based on the embodiment. The figure which shows a mode that an X-ray irradiation area | region and imaging | photography are performed based on the embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an X-ray image diagnostic apparatus 1 according to an embodiment. The X-ray diagnostic imaging apparatus 1 according to the embodiment includes an operation console 100, an X-ray control unit 201, a collimator control unit 202, a C arm driving unit 203, a top plate driving unit 204, an X-ray tube 301, an X-ray detector 302, Collimator 300,
It comprises a C arm 400 and a top plate 500. The configuration of the X-ray diagnostic imaging apparatus 1 is not limited to this, and appropriate components may be added or omitted. Further, the x-axis used in the description of the following embodiments indicates an axis perpendicular to the top plate 500, the y-axis indicates an axis parallel to the short direction of the top plate 500, and the z-axis indicates the length of the top plate 500. An axis parallel to the direction is shown.

In the embodiment described later, an operation for injecting a contrast medium into the body of the subject P in order to emphasize the blood vessels of the subject P and taking an X-ray image in a state where the contrast medium is injected into the body will be described. An X-ray image obtained by injecting a contrast medium into the body of the subject P and having the contrast medium present in the imaging region is referred to as a contrast image in the following description. On the other hand, an X-ray image taken in a state where no contrast medium is injected into the body of the subject P or in a state where no contrast medium exists in the imaging region is referred to as a mask image in the following description. In addition, an X-ray image generated by subtraction processing for calculating a difference between pixel values of a contrast image and a mask image is referred to as a subtraction image in the following description. In the following description, the X-ray image is used as a generic term for a contrast image, a mask image, and a subtraction image.

(Configuration of X-ray diagnostic imaging apparatus 1)
The operation console 100 is a CPU (Central Processing Unit).
), ROM (Read Only Memory) and RAM (Random Access)
s Memory). The operation console 100 includes an imaging control unit 101, an X-ray detector interface 102, an image processing unit 104, a storage unit 106, a display unit 107, an input unit 107, and the like, and processes signals supplied from the respective units. By generating various control signals and supplying them to the respective units, the X-ray image diagnostic apparatus 1 is comprehensively controlled.

When the X-ray image diagnostic apparatus 1 captures an X-ray image, the imaging control unit 101 includes an X-ray control unit 201,
Various control signals are output to the collimator control unit 202, the C arm drive unit 203, and the top panel control unit 204. Specifically, the X-ray beam irradiation signal for irradiating the X-ray tube 301 to the X-ray tube 301 is output to the X-ray control unit 201, and the collimator movement signal for moving the collimator 300 to change the X-ray irradiation area is collimated. The data is output to the unit 202.

In order to move the X-ray irradiation area in accordance with the moving contrast agent, the imaging control unit 101 outputs a C-arm drive signal for moving the C-arm to the C-arm drive unit 203 or moves the top 500. The top plate driving signal to be output is output to the top plate driving unit 204. In the following embodiments, as an example of the operation, it is described that the C-arm is moved when the X-ray irradiation region is moved. However, the present disclosure is not limited to this, and the X-ray irradiation area may be moved by moving the top plate instead of the C-arm.

The X-ray detector interface 102 converts an X-ray detection signal output when the X-ray detector 302 detects X-rays into an electric signal and outputs the electric signal to the image processing unit 104 or the storage unit 106.

The image processing unit 104 generates an X-ray image based on the electrical signal output from the X-ray detector interface 102. The image processing unit 104 outputs the generated X-ray image to the display unit 107 or the storage unit 106. In addition, the image processing unit 104 generates a subtraction image based on the mask image and the contrast image stored in the storage unit 106. A method for generating a subtraction image will be described in detail later. Further, the image processing unit 104 performs a process of generating a continuous large X-ray image by combining the X-ray images stored in the storage unit 106 by stitching them together. In addition, the image processing unit 104 performs processing for acquiring an image profile in a monitoring area, which will be described later, on the generated contrast image. This image profile is an index value indicating the distribution of pixel values.

Image profile acquisition processing will also be described in detail later. Further, the image processing unit 104 performs processing for calculating the moving speed of the contrast agent based on the generated contrast image. This movement speed calculation process is performed, for example, by extracting a region having a high pixel value in a contrast image, that is, a region in which a contrast agent is reflected, and calculating a speed at which this region moves in the contrast image. Image processing unit 10
4 extracts a speed component corresponding to the blood flow direction (+ z direction in FIG. 1), for example, as the contrast agent moving speed.

The storage unit 106 is configured by combining a storage medium such as a ROM, a RAM, a flash memory that is an electrically rewritable and erasable nonvolatile memory, or an HDD (Hard Disc Drive). The storage unit 106 stores the X-ray image generated by the image processing unit 104.

The display unit 107 is configured by a liquid crystal display, for example, and displays the X-ray image output from the image processing unit 104. The display unit 107 displays an operation screen for operating the X-ray image diagnostic apparatus 1, parameters of an input signal input from the input unit 108, and the like.

The input unit 108 includes, for example, a touch panel display and mechanical buttons,
An input operation performed on the input unit 108 by the user of the X-ray image diagnostic apparatus 1 is received. Input unit 10
8 outputs various instruction signals such as an X-ray beam irradiation instruction, a collimator movement instruction, a C-arm driving instruction, and a top board driving instruction to the imaging control unit 101 according to the received input operation.

The X-ray control unit 201 receives the X-ray beam irradiation signal output from the imaging control unit 101, and
A high voltage for irradiating the X-ray tube 301 with X-rays is applied. The application of the high voltage is performed along X-ray parameters specified by the X-ray beam irradiation signal, and the X-ray parameters specify parameters such as tube voltage, tube current, and X-ray pulse width.

The collimator control unit 202 receives the collimator movement signal output from the imaging control unit 101 and applies an electric signal that drives a motor attached to the collimator 300. The application of the electric signal is performed in accordance with the irradiation field parameter specified by the collimator movement signal.
Specify the position of.

The X-ray tube 301 receives the high voltage applied from the X-ray control unit 201 and irradiates X-rays toward the X-ray detector 302 provided so as to face the X-ray tube 301. The irradiated X-rays
The light passes through the collimator 300 and the subject P and enters the X-ray detector 302. When the X-ray passes through the collimator 300, the X-ray irradiation region 801 is narrowed, and when the X-ray passes through the subject P, its intensity changes.

The X-ray detector 302 detects X-rays emitted from the X-ray tube 301 and outputs an X-ray detection signal to the X-ray detector X.
Output to the line detector interface 102. The X-ray detector 302 is a so-called flat detector in which X-ray detection elements for detecting incident X-rays are two-dimensionally arranged. In this embodiment, an example in which the X-ray detector 302 is configured using a flat panel detector will be described, but the configuration of the present invention is not limited to this. For example, the X-ray detector 302 may be configured using various devices such as an image intensifier and a television camera.

The collimator 300 is a plate made of a material that shields X-rays such as lead and tungsten. A pair of collimators 300 are provided so as to limit the X-ray irradiation region 801 and block a part of the irradiated X-rays. A motor (not shown) is attached to the collimator 300, and the motor moves the collimator 300 with respect to the focal point of the X-ray tube 301 in accordance with a collimator movement signal output from the collimator control unit 202. In the present embodiment, as shown in FIG. 1, an example is shown in which a collimator 300 is configured from a first collimator 303 and a second collimator 304 that are arranged in the z-axis direction with an opening therebetween. First collimator 303 and second collimator 304
Are separately mounted with motors, each independently moving in the ± z direction. Hereinafter, the collimator 300 is used as a generic term for the first collimator 303 and the second collimator 304. The configuration of the collimator 300 is not limited to that shown in this embodiment, and the first collimator 3
In addition to 03 and the second collimator 304, a pair of collimators arranged in the y-axis direction may be further added.

The C arm drive unit 203 is configured by combining a plurality of rotary motors.
A motor for moving the collimator 300, the X-ray tube 301, and the X-ray detector 302 attached to the 0 and C arms. For example, the C-arm driving unit 203 is configured to connect the C-arm 400 to FIG.
A rotation motor that rotates the subject P with the y axis as a rotation center, a rotation motor that rotates the subject P with the z axis as a rotation center, a collimator 300, an X-ray tube 301, and an X-ray detector 3.
02 is a combination of a rotation motor that rotates the subject P with respect to the subject P about the x axis in FIG. 1 and a rotation motor that rotates the C arm 400 with respect to the floor surface about the x axis in FIG. Is done. The C-arm drive unit 203 drives each motor in accordance with the C-arm drive instruction signal output from the imaging control unit 101, and moves the C-arm and the collimator 300, the X-ray tube 301, and the X-ray detector 302 attached thereto. .

The C arm 400 is a C-shaped member attached to the C arm driving unit 203. A collimator 300 and an X-ray tube 301 are attached to one end of the C arm 400, and an X-ray detector 302 is attached to the other end so as to face the X-ray tube 301.

The top plate 500 is a plate-like member on which the subject P can be laid down. Top plate 50
0 is attached to the top plate drive unit 501, and a top plate drive unit 501 described later moves the top plate 500 along the longitudinal direction of the top plate 500 (the z-axis direction in FIG. 1).

The top plate driving unit 204 is a device for moving the top plate 500, which is configured by a motor (not shown) or the like. For example, the top plate driving unit 204 uses a belt connected to a motor as a top plate 500.
It is comprised by attaching to. The top panel drive unit 204 rotates the motor according to the top panel drive instruction signal output from the imaging control unit 101 to move the top panel 500 along the longitudinal direction of the top panel 500 (z-axis direction in FIG. 1).

(Control of X-ray irradiation area 801)
The X-ray image diagnostic apparatus 1 moves the collimator 300 to move the X-ray irradiation region 801.
To control. In the following, taking the operation of taking a single X-ray image while fixing the positional relationship among the X-ray tube 301, the X-ray detector 302 and the subject P as an example, the X-ray irradiation region 80 using the collimator 300 is taken.
The operation for controlling 1 will be described. FIG. 2 shows an X-ray irradiation area 80 by a collimator 300.
2 is a diagram illustrating a state in which an X-ray limited to 1 is incident on an X-ray detector 302 and an X-ray image generated by an image processing unit 104. FIG. In FIG. 2B and the following description, the width in the y direction of the X-ray irradiation region 801 is shown as being equivalent to the width of the X-ray detection region 802. In FIG. 2B and the subsequent drawings, the size of the X-ray irradiation region 801 is shown as a slightly smaller region than the actual size for convenience of drawing.

When the X-ray image diagnostic apparatus 1 captures an X-ray image, the subject P, the X-ray tube 301, and the X-ray detector 302 are aligned as a pre-stage of imaging. In this alignment, the C-arm drive unit 203 moves the C-arm 400 or the top-plate drive unit 204 moves the top plate 500 on which the subject P is placed, and the subject P and the X-ray tube 301 are moved. , And by changing the relative positional relationship with the X-ray detector 302.

When the alignment of the subject P is completed, the X-ray control unit 201 moves the collimator 300 to change the X-ray irradiation region 801. Specifically, the X-ray control unit 201 includes the first collimator 3.
By closing 03 and the second collimator 304, the opening of the collimator 300 is narrowed. As the opening of the collimator 300 is narrowed, X-rays are blocked, and as a result, the X-ray irradiation region 801 is narrowed.

When the movement of the collimator 300 is completed, the X-ray control unit 201 emits X-rays from the X-ray tube 301. The irradiated X-ray passes through the opening of the collimator 300 and enters the subject P. The X-rays incident on the subject P pass through the subject P and the top plate 500 and enter the X-ray detector 302. The image processing unit 104 generates an X-ray image 800 based on the electrical signal output from the X-ray detector interface 102. FIG. 2B shows a view of the subject P from the yz plane and an X-ray image 800 generated by the image processing unit 104. Since the X-rays blocked by the collimator 300 do not enter the X-ray detector 302, the X-ray image 800 is taken in an area where the X-ray irradiation area 801 and the X-ray detection area 802 overlap.

FIG. 3A shows a state in which the first collimator 303 and the second collimator 304 are respectively moved to the + z side. By moving the first collimator 303 and the second collimator 304 to the + z side, the X-ray irradiation region 801 also moves to the + z side. FIG. 3B shows the subject P.
FIG. 5 is a diagram of the image processing unit 104 viewed from the yz plane, and an X-ray image 800 generated by the image processing unit 104.

When X-rays are irradiated from the X-ray tube 301, the irradiated X-rays are blocked by the collimator 300,
The X-rays pass through the moved opening and enter the subject P and the X-ray detector 302. X-ray image 80
The area where 0 is imaged moves to the + z side as the X-ray irradiation area 801 moves.

What has been described above is the control of the X-ray irradiation region 801 using the collimator 300. By moving the collimator 300 and changing the X-ray irradiation region 801 on the X-ray detector 302, the X-ray image diagnostic apparatus 1 controls the position where the X-ray image 800 is taken.

When the region where an X-ray image is to be taken is outside the X-ray detection region 802, the X-ray image diagnostic apparatus 1 moves the C arm 400 instead of the collimator 300 to move the X-ray irradiation region 801.
And the X-ray detection area 802 are moved. The operation of moving the X-ray irradiation region 801 and the X-ray detection region 802 will be described below by taking as an example an operation of photographing one X-ray image with the size of the X-ray irradiation region 801 fixed. FIG. 4 is a diagram illustrating a state in which the C arm 400 is moved in the + z direction based on the positional relationship between the C arm 400 and the subject P illustrated in FIG. 2 and an X-ray image generated by the image processing unit 104. is there.

When the region where an X-ray image is to be taken is outside the X-ray detection region 802 of the X-ray detector 302 and on the + z side, the C-arm drive unit 203 moves the C-arm 400 to the + z side. As the C arm 400 moves to the + z side, the X-ray tube 301, the collimator 300, and the X-ray detector 302 attached to the C arm 400 move to the + z side with respect to the subject P.

When the movement of the C-arm 400 is completed, the X-ray control unit 201 moves the collimator 300 to change the X-ray irradiation region 801. When the movement of the collimator 300 is completed, the X-ray control unit 201 emits X-rays from the X-ray tube 301, and the image processing unit 104 generates an X-ray image 800 based on the X-rays incident on the X-ray detector 302. . FIG. 4B shows a view of the subject P from the yz plane, and an X-ray image 800 generated by the image processing unit 104. The position where the X-ray image 800 is taken is moved to the + z side as compared to FIG.

As described above, the X-ray irradiation region 801 and the X-ray detection region 802 by the C arm 400 are described.
Is a move. By moving the C-arm 400 to move the X-ray tube 301, the collimator 300, and the X-ray detector 302, the X-ray image diagnostic apparatus 1 moves the position where the X-ray image is taken. By combining the movement of the collimator 300 and the movement of the C-arm 400, X
The line image diagnostic apparatus 1 can take an X-ray image of an arbitrary size at an arbitrary position on the subject P. In the present embodiment, the C arm 400 is moved in the + z direction. However, the movement direction of the C arm 400 may be other directions such as the −z direction and the ± y direction. I do not care.

(Capturing contrast and subtraction images)
FIG. 5 shows a subject P into which a contrast medium has been injected, and a contrast image 810 when the subject P is imaged. In order to observe the blood flow of the subject P, the X-ray image diagnostic apparatus 1 takes a contrast image in a state where a contrast agent is injected into the blood vessel of the subject P. For example, when a contrast medium is injected into the artery of the subject P, the contrast medium passes through the peripheral capillary system and reaches the vein. Since the contrast agent is composed of a substance that shields X-rays, the blood flow of the subject P as shown in FIG. 5 is displayed when an X-ray image is taken in the presence of the contrast agent in the blood vessel. A contrast image is obtained. More specifically, in the contrast image 810, the body tissue of the subject P and the contrast agent flowing in the blood vessel are reflected in the X-ray image.

When an image in which blood flow is clinically highlighted is useful, the image processing unit 104 generates a subtraction image using the generated contrast image. In FIG. 6, the image processing unit 104 has a contrast image 810,
FIG. 10 is a diagram showing processing for generating a subtraction image 830 using a mask image 820. The mask image 820 is an X-ray image taken in a state where no contrast agent is present in the subject P. When the image processing unit 104 generates the contrast image 810, the image processing unit 104 generates a subtraction image 830 by performing subtraction processing with the mask image 820 generated in advance. The subtraction process is performed, for example, by calculating a difference between pixel values at the same coordinates of the contrast image 810 and the mask image 820 and mapping this difference value to the same coordinates of the subtraction image 830. The contrast image 810 reflects the body tissue and blood flow of the subject P, while the mask image 820.
Only the body tissue of the subject P is reflected. Therefore, the generated subtraction image 8
On 30, the body tissue reflected on both sides is subtracted and disappears, and a blood flow as a difference is displayed. The user of the X-ray diagnostic imaging apparatus 1 can observe the state of blood flow of the subject P from the subtraction image 830. In this embodiment, an example is shown in which the body tissue of the subject P is subtracted and disappears on the subtraction image 830, but the body tissue may be displayed lightly in the subtraction image. In order to display the body tissue lightly, the image processing unit 104 may weight the pixel values of the mask image 820 or the contrast image 810 and perform the subtraction process using the weighted image.

(Contrast imaging)
The contrast agent injected into the subject P at the time of capturing the contrast image described above moves in the subject P together with the blood flow. For example, when a contrast medium is injected into an artery in the thigh of the subject P, the contrast medium flows from the thigh to the toes and moves to the toes. Since the X-ray detection region of the X-ray detector 302 is usually narrower than the lower limb region, the X-ray diagnostic imaging apparatus 1 uses the contrast agent when generating a contrast image and a subtraction image over the entire lower limb of the subject P. The X-ray irradiation area 801 must be moved in accordance with the movement.

Therefore, in the X-ray image diagnostic apparatus 1 according to each embodiment, the moving contrast agent is controlled to be within the X-ray irradiation region 801 by moving the C arm 400 in accordance with the movement of the contrast agent. Furthermore, by moving the opening of the collimator 300 in accordance with the region where the contrast agent flows, the region where the imaging has been completed and the region where the contrast agent has not yet reached are irradiated X
Control to shield the line. Hereinafter, using the subtraction image, the lower limb of the subject P (hereinafter,
The operation of taking a mask image and a contrast image in accordance with the movement of the contrast agent will be described by taking as an example the case of observing the blood flow (which is simply referred to as an observation site).

FIG. 7 is a diagram showing the positional relationship between the subject P, the collimator 300, and the X-ray detector 302 immediately before injecting the contrast agent. As a previous stage of contrast imaging, the X-ray diagnostic imaging apparatus 1 moves the C-arm driving unit 203 and the top plate driving unit 204 to move the subject P, the X-ray tube 301, and the X-ray detector 302.
Perform position alignment. Specifically, this alignment is performed by the C-arm drive unit 203 using the C-arm 4.
00 or the top plate driving unit 204 moves the top plate 500 to move the X-ray detector 302 to the region in the observation site where the contrast agent is injected. In order to image the contrast agent moving to the downstream side of the blood flow (+ z direction in FIG. 7), the X-ray detector 302 moves the downstream side of the blood flow to the X-ray detection region 802 with respect to the contrast agent injection position. Located to fit.

When the alignment is completed, the X-ray control unit 201 moves the collimator 300. The first collimator 303 on the upstream side of the blood flow (the −z direction in FIG. 7) moves to the end of the X-ray detection region 802 of the X-ray detector 302, while the downstream side of the blood flow (in FIG. 7). The second collimator 304 in the (+ z direction) moves to a position that closes the middle of the X-ray detection region. That is, in the X-ray detection region 802, −
A half on the z side is an X-ray irradiation region 801.

When the movement of the collimator 300 is completed, the X-ray control unit 201 captures an X-ray image before injecting the contrast agent, and outputs this to the storage unit 106 as a mask image. In this embodiment, an example is described in which the first mask image is taken before the contrast agent is injected. However, the mask image is taken immediately after the contrast agent is injected, and the contrast agent reaches the X-ray detection region 802. It may be performed within the time until.

When imaging of the mask image is completed, a contrast agent is injected into the subject P. When the contrast agent is injected, the X-ray control unit 201 emits X-rays from the X-ray tube 301, and the image processing unit 104 starts generating a contrast image. The X-ray irradiation is performed, for example, in response to a user input operation using the input unit 108. FIG. 8A is a diagram showing a state immediately after the contrast medium is injected. The injected contrast agent moves toward the toe direction of the subject P (the + z direction in FIG. 8A). The X-ray tube 301 continuously irradiates the subject P with X-rays, and the image processing unit 104 generates contrast images one after another and outputs them to the storage unit 106 and the display unit 107. As a result, a contrast image in which the contrast medium moves along the bloodstream is displayed on the display unit 107 as a moving image that is updated in real time.

On the other hand, FIG. 8B is a display example of a control screen displayed in the display unit 107. For example, on the control screen, a positional relationship diagram 910 showing the relative positional relationship between the subject P, the collimator 300, and the X-ray detector 302, the name and ID (Identification) number of the subject P,
Control information 930 for displaying the user name and ID number, the flow rate information of the contrast medium flowing in the subject P, the cumulative dose of X-rays irradiated to the subject P, and the image processing unit 104 are generated. A contrast image 920 or the like is displayed. The contrast image 920 includes, for example, information indicating the positional relationship between the captured contrast image and the X-ray detection region 802 of the X-ray detector 302 (region indicated by a dotted line in FIG. 8B), and the aperture of the collimator 300. Position, that is, the position of the end of the first collimator 303 on the downstream side of the blood flow (in the + z direction in FIG. 8A) and the upstream side of the blood flow of the second collimator 304 (FIG. 8 (
The indicator which shows the position of the edge of b) in (b) and the indicator which shows the positional relationship of the monitoring area | region 921 mentioned later and a contrast image are superimposed and displayed. The user can confirm whether or not the X-ray irradiation area 801 and the position of the moving contrast agent coincide with each other with reference to the control screen displayed in the display unit 107.

FIG. 9A shows a contrast image monitoring area 921. The X-ray diagnostic imaging apparatus 1 according to the embodiment defines a monitoring region 921 in the captured contrast image, and determines whether or not the contrast agent has reached the position of the monitoring region 921 based on the pixel value in the monitoring region 921. to decide. More specifically, when the image processing unit 104 generates a contrast image and outputs it to the storage unit 106, the image processing unit 104 reads the contrast image and sets a monitoring region 921 in the contrast image. As shown in FIG. 9A, the image processing unit 104 is configured to monitor the monitoring region 9 at a position adjacent to the −z side end of the second collimator 304, for example.
21 is set. When the monitoring area 921 is set, the image processing unit 104 extracts the pixel value of the contrast image in the monitoring area 921 and calculates the distribution of the pixel value on the y axis. FIG. 9B shows a distribution of pixel values on the y-axis in the monitoring area 921. For example, when the lower limb of the subject P is photographed as shown in FIG. 9A, a contrast image is obtained such that the pixel value of the portion between the feet is high. The distribution of pixel values calculated by the image processing unit 104 appears as a shape reflecting this.

FIG. 10 is a diagram illustrating a state in which a contrast agent has reached the middle of the X-ray irradiation region 801 after a little time has elapsed from FIG. 9. The injected contrast agent further moves toward the + z direction as time passes. The contrast image generated by the image processing unit 104 also reflects the movement of the contrast agent and reflects the contrast agent that has moved to the middle of the contrast image.

FIG. 11 shows the monitoring region 921 of the contrast image at the time point shown in FIG. 10 and the distribution of pixel values on the y-axis. Since the contrast agent has not yet reached the monitoring region 921, the distribution of pixel values on the y axis is the same as the distribution immediately after the contrast agent injection.

FIG. 12 is a diagram showing a state at the time when the contrast medium reaches the monitoring region 921 after a little time has elapsed from FIG. The injected contrast medium further moves toward the + z direction as time elapses. On the contrast image 920 displayed on the display unit 107, a state in which the contrast agent has reached the monitoring area 921 is displayed. When it is detected that the contrast medium has reached the monitoring area 921 by a method described later, a message 940 indicating that the contrast medium has reached the monitoring area 921 is displayed on the display unit 107.

FIG. 13 shows the monitoring region 921 of the contrast image at the time point shown in FIG. 12 and the distribution of pixel values on the y-axis. Since the contrast agent is displayed with a low pixel value in the contrast image, the distribution of pixel values in the monitoring region 921 also changes as the contrast agent arrives. Specifically, when a contrast medium flows through a blood vessel located near the center of the foot, a peak corresponding to the position of the contrast medium appears in the graph indicating the distribution of pixel values. When the image processing unit 104 detects the appearance of a peak, the imaging control unit 10 sends a control signal indicating that the contrast agent has reached the monitoring area 921.
Output to 1. The peak detection may be performed, for example, by calculating the difference between the pixel value distribution immediately after the contrast agent injection and the pixel value distribution at a certain point in time, and when the difference exceeds a predetermined threshold. Absent. Alternatively, the pixel value distribution immediately after the contrast agent injection may be compared with the pixel value distribution at a certain point in time, and this may be triggered by a decrease in the number of y coordinates having pixel values equal to or greater than the threshold value. Alternatively, the pixel value at a certain point in time may be simply detected and triggered when the pixel value exceeds a threshold value.

When the imaging control unit 101 receives a control signal indicating that the contrast agent has reached the monitoring area 921, the imaging control unit 101 moves the collimator 300 in the + z direction using the collimator control unit 202.

FIG. 14A is a diagram illustrating a state in which the collimator is moved in the + z direction. Specifically, the collimator control unit 202 moves the second collimator 304 in the + z direction so that the −z side end of the second collimator 304 and the + z side end of the X-ray detection region 802 coincide with each other. The collimator control unit 202 moves the first collimator 303 in the + z direction, and moves the + z side end of the first collimator 303 to the middle of the X-ray detection region 802. As a result, the X-ray irradiation area 801 changes to the half of the X-ray detection area 802 on the + z side. When the movement of the collimator 300 ends, the imaging control unit 101 captures an X-ray image that is a still image before the contrast agent reaches the X-ray irradiation region 801. The image processing unit 104 outputs the generated X-ray image to the storage unit 106 as a mask image. The imaging control unit 101 starts imaging a contrast image immediately after imaging a mask image. This contrast image is taken in real time as a moving image, as described with reference to FIG.

FIG. 14B shows a display example of the control screen displayed in the display unit 107. Display unit 107
The collimator 300 displayed in the positional relationship diagram 910 as the collimator 300 moves.
Move the display position of. Further, the display unit 107 changes the display of the contrast image 920 in accordance with the movement of the X-ray irradiation region 801. Specifically, in the contrast image 920, in addition to the captured contrast image, a contrast image captured immediately before the movement of the collimator 300 is superimposed and displayed. That is, the contrast image currently being taken is displayed as a moving image in the right half of the contrast image 920 (+ z side in FIG. 14A), while the left half of the contrast image 920 (− in FIG. 14A). On the z side) the collimator 3
A contrast image taken immediately before 00 is displayed as a still image. In addition, the display method of the contrast image in the embodiment is not limited to this, and the display unit 107 does not superimpose the contrast image and displays a region not included in the X-ray irradiation region 801 by painting it with black or the like. It doesn't matter. The display unit 107 updates and displays the position of the indicator indicating the position of the opening in accordance with the moved collimator 300. Further, the image processing unit 104 moves the monitoring area 921 in accordance with the movement of the X-ray irradiation area 801 as will be described later. The display unit 107 updates and displays the position of the indicator indicating the monitoring area 921 in accordance with the moved monitoring area 921.

FIG. 15 shows a monitoring region 921 of the contrast image. When the collimator 300 moves and the X-ray irradiation area 801 changes, the image processing unit 104 monitors the monitoring area 9 in accordance with the change of the X-ray irradiation area 801.
Set 21 again. More specifically, the image processing unit 104, as shown in FIG.
For example, the monitoring region 921 is set at a position adjacent to the −z side end of the second collimator 304. When the monitoring area 921 is set, the image processing unit 104 calculates a distribution of pixel values on the y-axis in the monitoring area 921 as shown in FIG.

FIG. 16 is a diagram illustrating a state at the time when the contrast medium reaches the monitoring region 921 after a lapse of time from FIG. The injected contrast agent moves in the + z direction over time,
On the contrast image 920 displayed on the display unit 107, a state in which the contrast agent reaches the monitoring area 921 is displayed. When the image processing unit 104 detects that the contrast medium has reached the monitoring area 921, a message 940 indicating that the contrast medium has reached the monitoring area 921 is displayed on the display unit 107.

FIG. 17 shows a contrast-image monitoring region 921 at the time shown in FIG. 16 and the distribution of pixel values on the y-axis. As described with reference to FIG. 13, when the contrast agent reaches the monitoring area 921, a change in pixel value due to the contrast agent appears as a peak in the distribution of pixel values. Image processing unit 1
When 04 detects a peak, it outputs a control signal indicating that the contrast medium has reached the monitoring area 921 to the imaging control unit 101.

When the imaging control unit 101 receives a control signal indicating that the contrast medium has reached the monitoring area 921, the imaging control unit 101 uses the C arm driving unit 203 to move the C arm 400 in the + z direction. FIG.
FIG. 8A is a diagram illustrating a state in which the C-arm 400 is moved in the + z direction. Specifically, the C-arm drive unit 203 moves the C-arm 400 in the + z direction, and the + z side end in the X-ray detection region 802 before the movement and the −z side in the X-ray detection region 802 after the movement. Match the edges of As a result, the X-ray detection region 802 moves to the + z side in accordance with the moving contrast agent. When the C-arm drive unit 203 is used to move the C-arm 400, the imaging control unit 101 then uses the collimator control unit 202 to move the collimator 300 in the −z direction. Specifically, the collimator control unit 202 moves the first collimator 303 in the −z direction so that the + z side end of the first collimator 303 matches the −z side end in the X-ray detection region 802. In addition, the collimator control unit 202 moves the second collimator 304 in the −z direction, and moves the −z side end of the second collimator 304 to the middle of the X-ray detection region 802. As a result, the X-ray irradiation region 801 changes to a half on the −z side of the X-ray detection region 802. When the movement of the collimator 300 ends, the imaging control unit 101 captures an X-ray image that is a still image before the contrast agent reaches the X-ray detection region 802. The image processing unit 104 outputs the generated X-ray image to the storage unit 106 as a mask image. The imaging control unit 101 starts imaging a contrast image immediately after imaging a mask image. This contrast image is taken in real time as a moving image, as described with reference to FIG.

FIG. 18B shows a display example of the control screen displayed in the display unit 107. Display unit 107
Moves the display positions of the collimator 300 and the X-ray detector 302 displayed in the positional relationship diagram 910 in accordance with the movement of the C arm 400 and the collimator 300. In addition, the display unit 107
Displays a contrast image 920 that is newly imaged as the X-ray irradiation region 801 moves. Specifically, as shown in FIG. 18A, the display unit 107 displays the captured contrast image as a moving image on the left half of the contrast image 920. On the other hand, since the right half of the contrast image 920 is not included in the X-ray irradiation region 801, the display unit 107 displays nothing. The display unit 107 also includes a collimator 300.
Indicating the position of the opening of the monitor area 92 and the monitoring area 92 reset by the image processing unit 104
An indicator indicating the position of 1 is superimposed on the contrast image 920 and displayed.

The display unit 107 reduces and displays the contrast image 950 taken before the movement of the C arm 400. The contrast image 950 is displayed on the left half of the contrast image captured immediately before the movement of the collimator 300 described with reference to FIG. 14 and on the right half of the contrast image captured immediately before the movement of the C-arm 400. Two contrast images are joined together.

When the imaging control unit 101 starts imaging a contrast image, it repeats the detection of the contrast agent using the monitoring area 921 and the movement of the collimator 300 and the C arm 400 described with reference to FIGS. Continue shooting. When the X-ray irradiation area 801 reaches the end of the target area, the contrast medium reaches the monitoring area 921, or the X-ray irradiation area 801 reaches the end of the target area, and imaging of the contrast medium is performed for a certain time or more. If it continues, the imaging | photography control part 101 will complete | finish imaging | photography of a contrast image.

When the imaging control unit 101 finishes capturing a contrast image, the image processing unit 104 generates a subtraction image. As a pre-stage of generating the subtraction image, the image processing unit 104 first reads out the mask image stored in the storage unit 106 and combines the read mask images to combine a large mask image over the target area. The image processing unit 104 reads the contrast image stored in the storage unit 106 and combines the read contrast image to synthesize a large contrast image over the target region. The contrast image used for composition of the contrast image is the movement of the collimator 300 or the C-arm 4.
It is a contrast image taken immediately before the movement of 00, that is, when the contrast agent reaches the end of the X-ray irradiation region 801.

When the image processing unit 104 combines the mask image and the contrast image, the image processing unit 104 subtracts the mask image and the contrast image and generates a subtraction image. The generated subtraction image becomes a large subtraction image over the target region in the same manner as the combined mask image and contrast image. The user observes the state of blood flow in the target region using the generated subtraction image.

FIG. 19 is a flowchart illustrating processing performed by the imaging control unit 101 when imaging a contrast image. The processing flow will be described below using FIG. First, the imaging control unit 10
When 1 starts processing (step 1000), the imaging control unit 101 drives the X-ray control unit 201 before the contrast agent reaches the X-ray detection region 802 to capture an X-ray image, and the image processing unit 104
Is stored in the storage unit 106 as a mask image (step 1001). When the imaging control unit 101 finishes capturing a mask image, the imaging control unit 101 captures a contrast image (
Step 1002). The imaging control unit 101 waits for a control signal indicating that the contrast medium has reached the monitoring area 921 and continues to capture the contrast image until it is determined that the contrast medium has reached the monitoring area 921 ( Step 1003 No). When the image processing unit 104 determines that the contrast medium has reached the monitoring region 921 (Yes in step 1003), the imaging control unit 101 determines that the monitoring region 921 is located at the end of the X-ray detection region downstream (+ z direction in FIG. 1). It is determined whether or not they match (step 1004). When the imaging control unit 101 determines that the monitoring region 921 does not coincide with the downstream end of the X-ray detection region (No in step 1004), the collimator control unit 202 is used to move the collimator 300 to the downstream side (step 1005). ).

When the collimator control unit 202 completes the movement of the collimator 300, the imaging control unit 101 performs imaging of the mask image and imaging of the contrast image again (Step 1001 and Step 1002).

On the other hand, if the imaging control unit 101 determines that the monitoring area 921 matches the downstream end of the X-ray detection area (Yes in step 1004), then whether the monitoring area 921 matches the downstream end of the target area? It is determined whether or not (step 1006). The imaging control unit 101 includes a monitoring area 9
If it is determined that 21 does not coincide with the downstream end of the target area (No in step 1006), C
The C arm 400 is moved downstream using the arm driving unit 203 (step 1007).
. When the C-arm drive unit 203 finishes moving the C-arm 400, the collimator control unit 202
Moves the collimator 300 to the upstream side (the −z direction in FIG. 1) using the X-ray control unit 201. When the collimator control unit 202 completes the movement of the collimator 300, the imaging control unit 101 performs imaging of the mask image and imaging of the contrast image again (Step 1001 and Step 1).
002).

On the other hand, when the imaging control unit 101 determines that the monitoring area 921 coincides with the downstream end of the target area (step 1006), the imaging control unit 101 ends the process assuming that the imaging of the contrast image in the target area has ended (step 1009). ).

Through the above processing, the X-ray image diagnostic apparatus 1 according to the embodiment captures a contrast image. The X-ray diagnostic imaging apparatus 1 sets a monitoring region 921 in the captured contrast image, detects the arrival of the contrast agent based on a change in the pixel value in the monitoring region 921, and moves the collimator 300 and the C arm 400. Do.

Thereby, it is possible to reliably detect that the contrast agent has reached the end of the X-ray irradiation region 801 and to move the X-ray irradiation region 801 without imposing a burden on the user.

Further, through the above processing, the X-ray diagnostic imaging apparatus 1 of the embodiment moves the collimator 300 to the region where the contrast image has passed and the region where the contrast agent has not reached, and performs control so that X-rays are not irradiated. It is possible to prevent a situation where X-rays are irradiated to an area unnecessary for imaging a contrast image and reduce unnecessary exposure.

Further, through the above processing, the X-ray image diagnostic apparatus 1 according to the embodiment captures a mask image immediately before capturing a contrast image. By shortening the time interval between the imaging of the contrast image and the imaging of the mask image, the artifact in the subtraction image due to the body movement of the subject P can be suppressed.

Further, through the above processing, the X-ray image diagnostic apparatus 1 according to the embodiment controls the X-ray irradiation region by moving the collimator 300 in the processing of Step 1005. Since the X-ray tube 301 and the X-ray detector 302 attached to the C-arm 400 vibrate when the C-arm 400 moves, an artifact is generated in the X-ray image when the C-arm 400 is moved during imaging of the X-ray image. In the X-ray diagnostic imaging apparatus 1 according to the embodiment, the X-ray diagnostic imaging apparatus 1 is replaced by the movement of the collimator 300 instead of the C-arm 400.
Since the X-ray irradiation area during line image capturing is controlled, the occurrence of artifacts can be suppressed.

(Setting of monitoring area 921)
In the embodiment described above, the image processing unit 104 is located downstream of the imaging region (+ z in FIG. 1).
It has been stated that the monitoring area 921 is set at a position in contact with the end of the direction. However, the configuration of the X-ray diagnostic imaging apparatus 1 is not limited to this, and various monitoring area 921 setting methods may be used. FIG. 20 shows another setting example of the monitoring area 921. FIG. 20A is a diagram in which the monitoring region 921 is set so as to be in contact with the downstream end (+ z direction in FIG. 20) of the X-ray irradiation region 801 described in the above-described embodiment. As a modified example of the monitoring area 921, FIG.
As shown, the width of the monitoring region 921 in the z-axis direction may be increased. Monitoring area 921
By increasing the width in the z direction, the arrival of the contrast agent can be determined based on many pixels, and the contrast agent is caused by the influence of noise appearing in the contrast image and irregularity of the contrast agent movement. Detection errors can be prevented. As another modified example of the monitoring area 921, the monitoring area may be set at a position separated from the + z-direction end of the imaging area as shown in FIG. By setting the monitoring region at a separated position, even when the flow rate of the contrast agent is high, the movement of the contrast agent can be detected before the contrast agent reaches the end of the X-ray irradiation region 801. it can.

The area setting of these monitoring areas 921 may be performed according to, for example, the flow rate of the contrast agent in addition to the setting by the input unit 108. The image processing unit 104 detects the flow rate of the contrast agent based on the change in the pixel value of the generated contrast image. When the flow rate of the contrast agent is high, the image processing unit 104 widens the width of the monitoring region 921 in the z direction as shown in FIG. 20B, or the X-ray irradiation region 801 as shown in FIG. Is controlled so as to increase the distance from the end in the + z direction. Thereby, when the flow rate of the contrast agent is high, the movement of the contrast agent is detected earlier, and the collimator 300 and the C-arm 400 are surely moved before the contrast agent moves out of the X-ray irradiation region 801. be able to.

(Imaging area setting)
In the above-described embodiment, the example in which the imaging control unit 101 moves the collimator 300 so that the X-ray irradiation region 801 is approximately half of the X-ray detection region 802 has been described. However, the width of the X-ray irradiation region 801 is not limited to this, and the X-ray irradiation region 801 may be controlled to become narrower in order to reduce exposure. FIG. 21A shows a collimator 30.
The width of the 0 opening is narrowed, and the width of the X-ray irradiation region 801 is reduced to about 1/6 of the X-ray detection region 802.
It is an example.

FIG. 21 (b1, b2, b3) shows the positional relationship between the X-ray irradiation region 801, the X-ray detection region 802, the captured contrast image 920, and the monitoring region 921. Method for setting monitoring area 921 by image processing unit 104, method for detecting arrival of contrast medium using pixel value distribution, and collimator 30
The moving method of the 0 and the C arm 400 is the same as that described above with reference to FIGS. When the imaging control unit 101 starts imaging a contrast image, the imaging control unit 101 brings the second collimator 304 close to the first collimator 303 so that an X-ray irradiation region 801 shown in FIG. The image processing unit 104 sets a monitoring area 921 at a position in contact with the end of the X-ray irradiation area 801,
The arrival of the contrast agent is monitored based on the distribution of pixel values on the y-axis. When the contrast agent is injected into the subject P, the imaging control unit 101 starts imaging a contrast image, and the image processing unit 104 monitors the arrival of the contrast agent in the monitoring region 921 based on the generated contrast image.

When the image processing unit 104 determines that the contrast medium has reached the monitoring region 921, the collimator control unit 202 moves the first collimator 303 and the second collimator 304 to the downstream side (+ z direction in FIG. 21) of the blood flow. Then, control is performed so as to obtain an X-ray irradiation region 801 shown in FIG. After the collimator 300 moves, the imaging control unit 101 captures a mask image, and after capturing the mask image, the imaging control unit 101 starts capturing a contrast image. When this contrast agent monitoring and the movement of the collimator 300 are repeated, and the arrival of the contrast agent is detected in a state where the monitoring region 921 reaches the end of the X-ray detection region 802 as shown in FIG. The arm driving unit 203 moves the C-arm 400 to move the X-ray detection region 802.

According to the present embodiment in which the X-ray irradiation region 801 is narrowed, the region that does not contribute to the composition of the contrast image, such as a region where a contrast image has already been taken or a region where the contrast agent has not yet reached, is irradiated. X-rays are shielded by the collimator 300. Thereby, a contrast image can be taken with a smaller exposure dose. In this embodiment, the size of the X-ray irradiation region 801 is shown as about one-sixth of the X-ray detection region as an example. It does not matter if it can be set to.

(Movement control of the X-ray detection region 802 in consideration of the movement time of the collimator 300 and the C arm 400)
In each of the above-described embodiments, when the contrast agent reaches the end of the X-ray detection region 802, the C-arm drive unit 203 moves the C-arm 400 in the + z direction, and the X-ray detection region 8 before the movement is moved.
It was stated that the + z side end in 02 and the −z side end in the X-ray detection region 802 after movement are made to coincide. However, the X-ray irradiation region 801 by the C arm 400 and the collimator 300 is used.
It takes a certain time to move, and the contrast agent continues to move along the bloodstream while the X-ray irradiation region 801 is moving. For this reason, when the flow velocity is high, the contrast agent has already entered the X-ray irradiation region 801 when the movement of the X-ray irradiation region 801 or the X-ray detection region 802 is completed, and the mask image cannot be captured correctly. A situation is possible. To avoid this situation,
The C-arm 400 may be configured to move so that a part of the X-ray detection area before movement and a part of the X-ray detection area 802 after movement overlap.

FIG. 22 is a diagram illustrating a state in which the C arm driving unit 203 performs control so that a part of the X-ray detection region 802 overlaps before and after the C arm 400 moves. Hereinafter, the flow of taking a mask image and a contrast image will be described.

First, the imaging control unit 101 captures a mask image as a pre-stage of contrast image capturing. In order to capture a mask image, the imaging control unit 101 uses the C arm driving unit 203 to move the C arm 400 so that the region (1) to the region (3) fall within the X-ray detection region. Shooting control unit 1
In 01, when the C-arm 400 is moved, an X-ray image is taken. The image processing unit 104 stores the generated X-ray image in the storage unit 106 as a mask image (step 2000).

When imaging of the mask image is completed, the imaging control unit 101 starts imaging of the contrast image as the contrast agent is injected into the subject P (step 2001). In the imaging of the contrast image, the region (3) is shielded by the second collimator 304, while the first collimator 303 is retracted outside the X-ray detection region, and the region (1) and the region (2) are the imaging region. It is performed in the state. The image processing unit 104 sets the monitoring area 921 at a position in contact with the end of the area (2) on the bloodstream downstream side (+ z side in FIG. 22).

When the image processing unit 104 detects that the contrast medium has arrived at the monitoring region 921, the imaging control unit 101 moves the X-ray detection region 802 by moving the C arm 400 using the C arm driving unit 203. . At this time, the C-arm drive unit 203 moves from the region (3) to the region (5).
The C-arm 400 is moved so as to fit in the X-ray detection area 802. When the C-arm 400 is moved, the imaging control unit 101 moves the first collimator 303 so as to shield the region (3), while retracting the second collimator 304 out of the X-ray detection region 802 to obtain the X-ray. The irradiation region 801 is defined as a region (4) and a region (5). When the movement of the C-arm 400 and the first collimator 303 is completed, the imaging control unit 101 performs X-ray image imaging. The image processing unit 104 stores the generated X-ray image as a mask image in the storage unit 106 (step 2002).

When shooting of the mask image is completed, the imaging control unit 101 moves the first collimator 303 out of the X-ray detection area 802 again, and moves the second collimator 304 to a position where the area (5) is shielded. The X-ray irradiation region 801 is defined as a region (3) and a region (4). Shooting control unit 101
When the movement of the collimator 300 is completed, imaging of a contrast image is started (step 2003).
. The image processing unit 104 sets the monitoring area 921 at a position in contact with the + z side end of the area (4).

When the image processing unit 104 detects that the contrast medium has reached the monitoring area 921, the imaging control unit 101 moves the X-ray detection area 802 and captures a mask image again (step 2004).
). Imaging of the mask image is performed using the region (6) and the region (7) as the X-ray irradiation region 801.

When the imaging of the mask image is completed, the imaging control unit 101 moves the collimator 300 to the X-ray detection area 8.
The image is retreated outside of 02 and a contrast image is taken (step 2005). The image processing unit 104 sets the monitoring area 921 at a position in contact with the + z side end of the area (7).

When the image processing unit 104 detects that the contrast medium has reached the monitoring area 921, the imaging control unit 101 determines that imaging of the contrast image has ended. At this time, the storage unit 106 stores a mask image obtained by photographing the areas (1) to (3) in step 2000, a mask image obtained by photographing the areas (4) and (5) in step 2002, and an area ( 6) and a mask image obtained by photographing the region (7) are stored. The image processing unit 104 synthesizes these three mask images to synthesize a single mask image extending from the regions (1) to (7).

On the other hand, in the storage unit 106, a contrast image obtained by photographing the region (1) and the region (2) in step 2001, a contrast image obtained by photographing the region (3) and the region (4) in step 2003, and step 20
A contrast image obtained by capturing the region (5) to the region (7) in 05 is stored. The image processing unit 104 synthesizes these three contrast images, and synthesizes a single mask image covering the regions (1) to (7). When the synthesis of the mask image and the contrast image is completed, the image processing unit 104 performs subtraction processing to generate a subtraction image ranging from the region (1) to the region (7).

According to the above embodiment, the imaging control unit 101 captures a mask image and a contrast image while controlling the X-ray detection region 802 to partially overlap. As the moving distance of the C-arm 400 is shortened, the time taken to move the X-ray detection region 802 is shortened. As a result, the C-arm 40
Immediately after the movement of 0 and the collimator 30, the contrast agent moves into the X-ray detection region 802, and a situation in which the mask image cannot be correctly captured can be avoided.

In the present embodiment, the target area for contrast imaging is described as being divided into the area (1) to the area (7). However, the number of divided areas and the size of the areas are limited to those shown here. Without
The number of divisions may be increased or decreased appropriately.

In this embodiment, the X-ray detection area 802 is moved so that approximately one third of the X-ray detection area 802 overlaps. However, the size of the overlapping area is appropriately increased or decreased. You may make it. For example, when the moving speed of the contrast agent is high, it is necessary to enlarge the overlapping area and shorten the moving distance of the C arm 400. On the basis of the contrast image generated by the image processing unit 104, when the image processing unit 104 determines that the contrast agent has a high flow rate,
The imaging control unit 101 widens the divided area and the overlapping area, for example, about 2 of the X-ray detection area 802.
You may control so that it may become 1 /. When the image processing unit 104 determines that the flow rate of the contrast medium is slow, the imaging control unit 101 narrows the divided region and the overlapping region, and the overlapping region becomes, for example, about one quarter of the X-ray detection region 802. You may control as follows. Alternatively, the number of divisions and the size of the overlapping area may be set by an input operation using the input unit 108.

Note that the configuration of the X-ray diagnostic imaging apparatus 1 of the present disclosure is not limited to that disclosed in each embodiment. For example, in each embodiment, the operation of capturing a mask image immediately before capturing a contrast image has been described. However, the imaging order of X-ray images is not limited to this. For example, a mask image of the entire target region is imaged, and after the imaging of the mask image is completed, a contrast medium is injected into the subject P, and a contrast image is imaged. You may perform the operation to do.

In each embodiment, the case where the lower limb of the subject P is imaged as an example has been described. However, other parts such as the upper limb and the abdomen of the subject P may be imaged.

In each embodiment, an example in which the arrival of a contrast agent is detected based on a change in the distribution of pixel values on the y-axis has been described, but the method for detecting a contrast agent is not limited to this. For example, the pixel value image processing unit 104 may calculate a histogram related to the pixel value in the monitoring region 921 and detect the arrival of the contrast agent based on the change in the histogram of the pixel value. Specifically, when the contrast agent reaches the monitoring area 921, pixels having a low pixel value among the pixel values in the monitoring area 921 increase. In the histogram, this change appears in the form of an increase in the appearance frequency of low-value pixel values. For example, the image processing unit 104 detects that the contrast agent has reached the monitoring area 921 based on the change amount of the histogram exceeding a predetermined threshold.

Further, in each of the embodiments described with reference to FIG. 8 and the like, it is described that the display unit 107 displays the contrast image 920 during the imaging of the contrast image, but the subtraction image is displayed instead of the contrast image 920. It doesn't matter. In this case, the image processing unit 104 performs a subtraction process between the contrast image output in real time and the mask image stored in the storage unit 106. Display unit 10
7 displays the subtraction image as a moving image updated in real time.

In each embodiment, an example in which the X-ray image diagnostic apparatus 1 is configured using the C-arm 400 has been described. Vessel 3
02 may operate independently, or the X-ray detector 302 and the top plate 500 may be integrated as a bed. Further, for example, some components may be deleted from all the components shown in each embodiment. Or you may combine the component covering a different Example suitably.

1 X-ray diagnostic imaging apparatus 100 Operation console 101 Imaging control unit 102 X-ray detector interface 104 Image processing unit 106 Storage unit 107 Display unit 108 Input unit 201 X-ray control unit 202 Collimator control unit 203 C-arm drive unit 204 Top plate drive Unit 300 Collimator 301 X-ray tube 302 X-ray detector 303 First collimator 304 Second collimator 400 C-arm 500 Top plate 800 X-ray image 801 X-ray irradiation area 802 X-ray detection area 810 Contrast image 820 Mask image 830 Subtraction image 910 Positional relationship diagram 920 Contrast image 921 Monitoring area 930 Control information

Claims (7)

An X-ray tube that emits X-rays;
A collimator that blocks at least a part of the X-ray and narrows the irradiation region of the X-ray;
Imaging means for generating an X-ray image by detecting the X-ray whose irradiation area is narrowed by the collimator;
Holding means for holding the X-ray tube, the collimator, and the imaging means;
First moving means for moving the collimator;
Second moving means for moving the holding means;
An X-ray diagnostic imaging apparatus comprising: a control unit that controls the first and second moving units to move the holding unit according to the movement of the collimator based on a movement instruction signal. The controller is
The control is performed based on the movement instruction signal so as to switch between a first movement for moving the collimator and a second movement for moving the collimator and the holding means. The X-ray diagnostic imaging apparatus described. An operation unit that accepts input operations;
Monitoring area setting means for setting a monitoring area in the X-ray image;
Detecting means for detecting a contrast agent reflected in the monitoring area based on the X-ray image;
The said control part produces | generates the said movement instruction | indication signal based on at least any one of the input operation which the said operation part received, or the detection of the contrast agent by the said detection means. X-ray diagnostic imaging equipment. The monitoring area setting means sets a first monitoring area set corresponding to the irradiation area and a second monitoring area set corresponding to the X-ray detection area of the imaging means. ,
The first moving means moves the collimator based on the detection means detecting the contrast agent in the first monitoring region,
The X-ray image diagnostic apparatus according to claim 3, wherein the second moving unit moves the holding unit and the collimator based on the detection unit detecting the contrast agent in the second monitoring region. The first moving means moves the collimator to move the irradiation range in the downstream direction of the contrast agent flow,
The X-ray according to claim 3 or 4, wherein the second moving means moves the holding unit and the collimator so as to move the irradiation range and the X-ray detection region in a downstream direction of the flow of the contrast agent. Diagnostic imaging device. Subtraction means for generating a subtraction image based on the X-ray image and the mask image,
The imaging means captures a mask image in response to movement of the collimator by the first moving means or movement of the holding means and the collimator by the second moving means. Item 6. The X-ray image diagnostic apparatus according to any one of Items 1 to 5. A moving speed calculating means for calculating a moving speed of the contrast agent based on the X-ray image;
The X-ray image diagnostic apparatus according to claim 1, wherein the first and second moving units change a movement amount based on the movement speed calculated by the movement speed calculation unit.

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