JP2020130237A - X-ray diagnostic apparatus - Google Patents

Abstract

To reduce the burden and exposure dose to the patient when performing examination by an X-ray diagnostic apparatus.SOLUTION: A first imaging function (first imaging unit) causes an X-ray tube to project a first dose and performs rotation imaging (first imaging) for generating a projection image (image), while rotating, around a subject, an imaging device that includes the X-ray tube (X-ray source) and an X-ray detector having a plurality of pixels for detecting the intensity of X-rays transmitted through the subject. When the rotation imaging is interrupted, a first moving function (first moving unit) moves the imaging device to a first position according to the interruption position. A second imaging function (second imaging unit) projects, at the first position, X-rays of a second dose lower than the first dose to generate a fluoroscopic image (projection image). A first restart instruction function (first restart instruction unit) restarts rotation imaging when the imaging device, which restarts rotation upon the fluoroscopic image satisfying a predetermined condition, reaches the interruption position of rotation imaging.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to an X-ray diagnostic apparatus.

In an X-ray diagnostic device that captures the projected data of X-rays irradiated to a patient and observes the state of blood vessels, the imaging of the projected data is interrupted due to changes in the position due to the movement of the patient. There is. In such a case, reimaging is performed, but there is a problem that the burden on the patient and the exposure dose of X-rays increase with the reimaging.

Japanese Unexamined Patent Publication No. 8-196532

An object to be solved by the present invention is to reduce the burden on the patient and the radiation dose when making a diagnosis by the X-ray diagnostic apparatus.

The X-ray diagnostic apparatus according to the embodiment includes a first imaging unit, a first moving unit, a second imaging unit, and a first restart instruction unit. The first imaging unit provides an imaging device including an X-ray source for irradiating X-rays and an X-ray detector having a plurality of pixels for detecting the intensity of X-rays transmitted through the subject around the subject. While rotating and moving over, the X-ray source is irradiated with the first dose, and the first imaging is performed to generate an image based on the intensity of the X-ray transmitted through the subject. When the first imaging is interrupted, the first moving unit moves the imaging device to a first position according to the position where the first imaging is interrupted. The second imaging unit irradiates the X-ray source with a second dose lower than the first dose at the first position to generate an image based on the intensity of the X-ray transmitted through the subject. Is imaged. The first restart instruction unit restarts the rotational movement of the imaging device on condition that the image generated by the second imaging satisfies a predetermined condition, and the imaging device performs the first imaging. On condition that the interrupted position is reached, the first imaging unit restarts the first imaging.

FIG. 1 is a block diagram showing a configuration example of the X-ray diagnostic apparatus according to the first embodiment. FIG. 2 is a diagram illustrating an imaging device according to the first embodiment. FIG. 3 is a diagram illustrating a rotation imaging performed by the X-ray diagnostic apparatus according to the first embodiment. FIG. 4 is a diagram illustrating a method in which the X-ray diagnostic apparatus according to the first embodiment generates a reference image. FIG. 5 is a diagram illustrating an outline of a flow of rotational imaging performed by the X-ray diagnostic apparatus according to the first embodiment. FIG. 6 is a flowchart showing an example of the procedure of rotation imaging performed by the X-ray diagnostic apparatus according to the first embodiment. FIG. 7 is a block diagram showing a configuration example of a processing circuit of the X-ray diagnostic apparatus according to the second embodiment. FIG. 8 is a diagram illustrating a rotation imaging performed by the X-ray diagnostic apparatus according to the second embodiment. FIG. 9 is a diagram illustrating an outline of a flow of rotational imaging performed by the X-ray diagnostic apparatus according to the second embodiment. FIG. 10 is a flowchart showing an example of the procedure of rotation imaging performed by the X-ray diagnostic apparatus according to the second embodiment. FIG. 11 is a block diagram showing a configuration example of a processing circuit of the X-ray diagnostic apparatus according to the modified example of the second embodiment. FIG. 12 is a block diagram showing a configuration example of a processing circuit of the X-ray diagnostic apparatus according to the third embodiment. FIG. 13 is a flowchart showing an example of a processing procedure performed by the X-ray diagnostic apparatus according to the third embodiment.

Hereinafter, embodiments of the X-ray diagnostic apparatus will be described in detail with reference to the drawings. The X-ray diagnostic apparatus according to the present application is not limited to the embodiments shown below.

(First Embodiment)
FIG. 1 is a diagram showing an example of the configuration of the X-ray diagnostic apparatus 1 according to the first embodiment. The X-ray diagnostic apparatus 1 is an apparatus for observing the state of blood vessels of a patient in real time. Physicians make a diagnosis by continuously observing images in which blood vessels are emphasized by injection of contrast medium. As shown in FIG. 1, the X-ray diagnostic apparatus 1 includes an image pickup apparatus 10 and an image processing apparatus 100.

(Explanation of the overall configuration of the X-ray diagnostic device)
The image pickup apparatus 10 includes an X-ray tube 11, an X-ray detector 12, and a C-type arm 13. Further, an injector 60 is connected to the image pickup apparatus 10. The subject P, such as a patient, is placed between the X-ray tube 11 and the X-ray detector 12 while lying down on the bed 14. The configuration of the imaging device 10 will be described in detail later (FIG. 2).

The injector 60 is a device for injecting a contrast medium from a catheter inserted into the subject P. The contrast medium injection from the injector 60 may be executed according to the injection start instruction received from the image processing device 100 described later, or is executed according to the injection start instruction directly input to the injector 60 by an operator such as an operator. You may.

The C-shaped arm 13 supports an X-ray tube 11 and an X-ray detector 12 that detects X-rays emitted from the X-ray tube 11. The C-shaped arm 13 is rotationally moved around the subject P lying on the bed 14 by a motor (not shown). Here, the C-shaped arm 13 is rotatably supported with respect to the XYZ axes, which are three orthogonal axes, and is rotated around each axis by a drive unit (not shown).

The X-ray tube 11 generates X-rays using a high voltage supplied from a high voltage generator (not shown). The X-ray tube 11 is an example of an X-ray source. The X-ray detector 12 is a matrix of a plurality of X-ray detection elements that detect X-rays that have been irradiated from the X-ray tube 11 and transmitted through the subject P. The X-ray detector 12 detects the X-rays that have passed through the subject P, and detects the intensity of the X-rays that have passed through the subject P. Then, the X-ray detector 12 outputs the detected X-ray intensity to the A / D converter 21, which will be described later.

As shown in FIG. 1, the image processing apparatus 100 includes an A / D (Analog / Digital) converter 21, an image memory 22, an image pickup control circuit 23, a movement control circuit 24, an affine conversion circuit 25, and 3. It has a dimensional reconstruction circuit 26, a processing circuit 30a, a display 40, and an input interface 50.

The display 40 displays various images processed by the image processing device 100 and various information such as a GUI (Graphical User Interface). For example, the display 40 is a liquid crystal monitor, a CRT (Cathode Ray Tube) monitor, or the like.

The input interface 50 corresponds to an input device such as a mouse, a keyboard, a button, a panel switch, a touch command screen, a foot switch, a trackball, and a joystick. The input interface 50 receives various instructions from the operator. Then, the input interface 50 appropriately transfers the received various instructions to each circuit of the image processing device 100.

For example, the input interface 50 includes an X-ray trigger button for instructing X-ray irradiation. When the X-ray trigger button is pressed by the operator, the X-ray diagnostic apparatus 1 starts imaging the X-ray image data. Further, for example, the input interface 50 includes a device drive button for instructing a change in the irradiation direction of X-rays. When the device drive button is pressed by the operator, the X-ray diagnostic device 1 changes the X-ray irradiation direction by rotating and moving the C-type arm 13 in a preset direction. Further, the input interface 50 includes an interrupt button for interrupting the imaging of the X-ray image data. When the interrupt button is pressed by the operator, the X-ray diagnostic apparatus 1 interrupts the imaging of the X-ray image data.

The A / D converter 21 is connected to the X-ray detector 12, converts the analog signal input from the X-ray detector 12 into a digital signal, and stores the converted digital signal as X-ray image data in the image memory 22. To do.

The image memory 22 stores X-ray image data converted into a digital signal by the A / D converter 21. Further, the image memory 22 stores reconstruction data (volume data) reconstructed by the three-dimensional reconstruction circuit 26 described later. The image memory 22 can store a program that can be executed by a computer.

The image pickup control circuit 23 controls various processes related to image pickup by the image pickup apparatus 10 under the control of the processing circuit 30a described later. For example, the image pickup control circuit 23 causes the C-type arm 13 to rotate and move to perform the first image pickup in which the X-ray image data is imaged at a predetermined frame rate. In the following description, the first imaging is referred to as rotation imaging. As an example, the imaging control circuit 23 rotates and images, for example, 15 X-ray image data per second after injecting a contrast medium from the injector 60.

Further, the imaging control circuit 23 controls a high voltage generator (not shown) to generate a first dose of X-rays from the X-ray tube 11 while the processing circuit 30a is rotating and moving around the C-type arm 13. The X-ray detector 12 controls so as to detect the intensity of the X-ray transmitted through the subject P. Further, the imaging control circuit 23 controls a high voltage generator (not shown) while the processing circuit 30a stops the C-type arm 13, and a second dose lower than the first dose from the X-ray tube 11. X-rays are generated and controlled so that the X-ray detector 12 detects the intensity of the X-rays that have passed through the subject P.

The movement control circuit 24 controls the position (angle) of the C-type arm 13 under the control of the processing circuit 30a. Details will be described later.

The affine transformation circuit 25 performs translation, rotation, and scaling of the X-ray image data described above to appropriately correct the X-ray image data. Details will be described later.

The three-dimensional reconstruction circuit 26 reconstructs the reconstruction data (volume data) from the X-ray image data collected by the rotation imaging by the imaging device 10. Then, the three-dimensional reconstruction circuit 26 stores the reconstructed volume data in the image memory 22.

The processing circuit 30a controls the entire operation of the X-ray diagnostic apparatus 1. Specifically, the processing circuit 30a instructs the start, interruption, and resumption of rotational imaging by the imaging device 10. Further, the processing circuit 30a determines the rotation start position of the image pickup apparatus 10 when restarting the rotation imaging, and moves the image pickup apparatus 10 to the rotation start position. Further, the processing circuit 30a determines the timing for restarting the rotation imaging by monitoring the captured image at the rotation start position.

The processing circuit 30a includes a first image pickup function 301a, a second image pickup function 301b, a first movement function 302a, a first restart instruction function 304a, a reconstruction function 308, a deviation calculation function 309, and the like. The display control function 310 is executed. The detailed contents of each function will be described later.

The processing content executed by each processing function that is a component of the processing circuit 30 is recorded in the storage device of the X-ray diagnostic apparatus 1 in the form of a program that can be executed by a computer. The storage device is, for example, an image memory 22, a RAM (Random Access Memory) or a ROM (Read Only Memory) included in the processing circuit 30a, and the like. The processing circuit 30a is a processor that includes a CPU (Central Processing Unit) (not shown) and realizes a function corresponding to each program by reading each program from a storage device and executing the program. In other words, the processing circuit 30a in the state where each program is read out has each function shown in the processing circuit 30a of FIG.

The content shown in FIG. 1 is only an example. For example, the circuits illustrated in FIG. 1 do not necessarily have to be configured independently. For example, any circuit among these circuits may be appropriately combined and configured.

In addition to the CPU described above, the "processor" in the above description includes, for example, a GPU (Graphics Processing Unit), an integrated circuit for a specific application (Application Specific Integrated Circuit: ASIC), or a programmable logic device (for example, a simple programmable device). It means a circuit such as a logical device (Simple Programmable Logic Device: SPLD), a complex programmable logic device (CPLD), and a field programmable gate array (FPGA). The processor realizes the function by reading and executing the program stored in the storage device. Instead of storing the program in the storage device, the program may be directly embedded in the circuit of the processor. In this case, the processor realizes the function by reading and executing the program embedded in the circuit. It should be noted that each processor of the present embodiment is not limited to the case where each processor is configured as a single circuit, and a plurality of independent circuits may be combined to form one processor to realize its function. Good.

(Explanation of X-ray detector)
Next, the configuration of the image pickup apparatus 10 will be specifically described with reference to FIG. The image pickup apparatus 10 irradiates X-rays having a spread from the X-ray tube 11 along the X-axis direction and the Z-axis direction. The spread angle along the X-axis direction (spread angle on the XY plane) is called a fan angle. Further, the spread angle along the Z-axis direction (spread angle on the YZ plane) is called a cone angle.

The X-rays emitted from the X-ray tube 11 pass through the subject P and reach the X-ray detector 12 installed at a position facing the X-ray tube 11. The X-ray detector 12 is a two-dimensional image sensor on a plane provided so as to face the focal point of the X-ray tube 11. Each pixel constituting the X-ray detector 12 is specified by a position in the x-axis direction along the direction of the fan angle and a position in the y-axis direction along the direction of the cone angle. The X-ray detector 12 receives X-rays irradiated from the X-ray tube 11 and transmitted through the subject P, and outputs X-ray intensity data for each coordinate (x, y). The above-mentioned X-ray image data represents the X-ray intensity data for each coordinate (x, y) as an image. The X-ray intensity data obtained in this way is referred to as a projected image I (x, y) in the following description.

The X-ray tube 11 and the X-ray detector 12 are connected by the C-shaped arm 13 shown in FIG. 1, and the image pickup apparatus 10 rotates around the Z axis to project the subject P in an arbitrary direction. Image I (x, y) is imaged. The projected image I (x, y) is given the rotation angle ω of the imaging device 10 when the projected image I (x, y) is generated as incidental information. In the following description, when the rotation angle ω of the image pickup apparatus 10 is meaningful, the projected image I (x, y) is described as a projected image I (x, y, ω) in particular.

According to the imaging device 10 shown in FIG. 2, the projected image I (x, y) in a range corresponding to the cone angle along the y-axis direction of the subject P is imaged by one rotational movement of the C-shaped arm 13. Can be done. Such an imaging method is generally called CBCT (Corn Beam CT) imaging.

(Explanation of functional configuration of processing circuit)
Hereinafter, the contents of each function constituting the processing circuit 30a will be described.

The first imaging function 301a comprises an imaging device 10 including an X-ray tube 11 for irradiating X-rays and an X-ray detector 12 having a plurality of pixels for detecting the intensity of X-rays transmitted through the subject P. The first imaging (hereinafter referred to as rotation) in which the X-ray tube 11 is irradiated with the first dose while rotating and moving around the subject P to generate an image based on the intensity of the X-ray transmitted through the subject P. (Called imaging).

Specifically, the first imaging function 301a controls the movement control circuit 24 to rotate and move the imaging device 10 at a predetermined speed (steady speed v) to the imaging control circuit 23. The projected image I (x, y) corresponding to the direction of the image pickup apparatus 10 is imaged at a predetermined timing (for example, 15 frames per second). In addition, the first imaging function 301a interrupts the rotation imaging in response to an instruction from a doctor or the like operating the X-ray diagnostic apparatus 1. For example, when the subject P (for example, a patient) moves due to body movement or the like during rotation imaging, the rotation imaging is interrupted by detecting the operation of the interrupt button described above. Further, the first imaging function 301a determines that the rotation imaging is completed on condition that the imaging device 10 has reached the end position of the rotation imaging. Further, the first imaging function 301a instructs the injector 60 to inject the contrast medium. The first imaging function 301a is an example of the first imaging unit.

In the first moving function 302a, when the rotation imaging (first imaging) by the first imaging function 301a is interrupted, the imaging device 10 is moved to the point S2 according to the position where the rotation imaging is interrupted, that is, the said. Move to the rotation start position. The first moving function 302a is an example of the first moving unit. The point S2 is an example of the first position. When the rotation imaging is interrupted, the position and orientation of the subject P are deviated. Therefore, the first moving function 302a sets the imaging device 10 at the point S2 after returning the subject P to the original position. Move to.

The second imaging function 301b irradiates the X-ray tube 11 with a second dose lower than the first dose at the point S2 to generate an image based on the intensity of the X-ray transmitted through the subject P. 2 is imaged. The projected image I (x, y, ω3) (ω3 is the rotation angle corresponding to the position of the point S2) captured at this time is particularly referred to as a fluoroscopic image T (x, y, ω3). Further, in the following description, the second imaging is referred to as fluoroscopy. The second imaging function 301b is an example of the second imaging unit.

The first restart instruction function 304a rotates and moves the image pickup apparatus 10 on condition that the fluoroscopic image T (x, y, ω3) generated by the second image pickup function 301b is determined to satisfy a predetermined condition. To resume. Further, the first restart instruction function 304a causes the first imaging function 301a to restart the rotation imaging on condition that the imaging device 10 reaches the position where the rotation imaging (first imaging) is interrupted. The first restart instruction function 304a is an example of the first restart instruction unit. The predetermined conditions will be described later (FIG. 4).

In order to make the following explanation easier to understand, the projected image of the first cut captured before the interruption of the rotation imaging is represented by I1 (x, y). Further, the projected image of the second cut captured after the resumption of the rotation imaging is represented by I2 (x, y). When representing a general projected image, it is described as a projected image I (x, y).

The reconstruction function 308 is a projection image I1 (x, y) of the first cut imaged by the first imaging function 301a before the interruption of the rotation imaging (first imaging) with respect to the deviation calculation function 307 described later. And, after resuming the rotation imaging (first imaging), the deviation from the projected image I2 (x, y) of the second cut imaged by the first imaging function 301a is calculated. Further, the reconstruction function 308 corrects the projected image I1 (x, y) of the first cut or the projected image I2 (x, y) of the second cut based on the deviation calculated by the deviation calculation function 309. Further, the reconstruction function 308 obtains a reconstruction image which is a cross-sectional view of the subject P from the corrected projection image I1 (x, y) of the first cut and the projection image I2 (x, y) of the second cut. Generate. The reconstruction function 308 is an example of the reconstruction unit.

The deviation calculation function 309 calculates the deviation between the projected image I1 (x, y) of the first cut and the projected image I2 (x, y) of the second cut based on the instruction of the reconstruction function 308. The deviation calculation function 309 is an example of the deviation calculation unit.

The display control function 310 displays various images (projected image of the first cut, projected image of the second cut, perspective view) acquired by the X-ray diagnostic device 1 on the display 40 in response to an instruction from the operator of the X-ray diagnostic device 1. Images, reconstructed images, etc.) are displayed.

(Explanation of rotation imaging operation)
FIG. 3 is a diagram illustrating a rotation imaging performed by the X-ray diagnostic apparatus 1 according to the first embodiment. The image pickup apparatus 10 starts rotation from the point S0 (ω = ω0), starts rotation imaging from the point S1 (ω = ω1) that reaches a predetermined steady speed v, and generates a projected image of the first cut. When the patient (subject P) moves during the rotary imaging of the first cut, the imaging device 10 receives an instruction from a doctor or the like and at a position where the movement of the patient is confirmed (for example, point Q (ω = ω2)). The rotation imaging is interrupted. That is, as the projected image of the first cut, the projected image I (x, y) from the point S1 to the point Q is imaged.

When the rotation imaging is interrupted, as shown in FIG. 3, the imaging device 10 moves to the point S2 (ω = ω3) according to the instruction of the first moving function 302a. The point S2 is determined so that the imaging device 10 that has received the instruction to restart the rotation moves at a predetermined steady speed v at the point Q. Details will be described later.

Then, the image pickup apparatus 10 that has resumed rotation at the point S2 starts the rotation imaging of the second cut at the point Q according to the instruction of the first restart instruction function 304a. The rotary imaging of the second cut ends at a predetermined point S3 (ω = ω4). That is, as the projected image of the second cut, the projected image I (x, y) from the point Q to the point S3 is imaged. The method of determining the timing at which the image pickup apparatus 10 resumes rotation at point S2 will be described later.

(Explanation of movement processing of X-ray detector)
The first movement function 302a determines the position (first position) of the point S2 so that the imaging device 10 that has started the rotational movement at the point S2 reaches the steady speed v at the position where the rotational imaging is interrupted. .. Hereinafter, a specific method for obtaining the position of the point S2 will be described. It is assumed that the image pickup apparatus 10 acquires 15 projected images I (x, y) per second while rotating and moving at a steady speed v (for example, 25 deg / sec). Further, it is assumed that the acceleration time To required for the stopped imaging device 10 to start rotating and reach the steady speed v is 1.2 sec.

The first movement function 302a determines the position of the point S2 based on the time (acceleration time To) required from the start of the rotational movement of the imaging device 10 to reach the steady speed v and the steady speed v. .. Specifically, the rotation angle ωa until the image pickup apparatus 10 reaches the steady speed v is calculated by (Equation 1).

ωa = (1/2) * (v / T) * T ² = vT / 2 = 15deg (Equation 1)

Then, the first movement function 302a moves the imaging device 10 by 15 deg from the point Q (ω = ω2) where the rotation imaging is interrupted to the point S2 (ω = ω3).

(Explanation of fluoroscopic operation)
Next, at the point S2, a method of determining the timing at which the image pickup apparatus 10 resumes the rotational movement will be described. When making a diagnosis with the X-ray diagnostic apparatus 1, the shape of the blood vessel and the state of the blood vessel (presence or absence of clogging, etc.) are generally observed by injecting a contrast medium into the blood vessel. In the case of injecting a contrast medium in this way for diagnosis, when the rotation imaging is interrupted, the position of the contrast medium in the blood vessel of interest (hereinafter referred to as the blood vessel of interest) and when the rotation imaging is restarted. It is necessary to match the position of the contrast medium in the blood vessel of interest. The contrast medium is injected from the injector 60 described above, but when the contrast medium is injected manually by a doctor or the like, the position of the contrast medium in the blood vessel of interest is monitored to determine when to resume rotational imaging. There is a need.

In the X-ray diagnostic apparatus 1 of the present embodiment, with the imaging apparatus 10 stopped at the point S2, the second imaging function 301b irradiates the subject P with the first dose when performing rotational imaging. On the other hand, a smaller second dose of X-rays is irradiated to perform imaging of the fluoroscopic image T (x, y, ω3) (second imaging), that is, fluoroscopy. Then, the first restart instruction function 304a monitors the captured fluoroscopic image T (x, y, ω3) and determines the timing for restarting the rotation imaging.

The exposure dose of the subject P can be reduced by making the dose of X-rays to be irradiated when performing fluoroscopy smaller than the dose to be irradiated when performing rotational imaging.

The first restart instruction function 304a is the subject P in the projected image I (x, y) generated by the first imaging at a position corresponding to a time ta before a predetermined time ta from the point S2 (first position). On condition that the predicted position of the contrast medium injected into the image at the point S2 and the position of the contrast medium in the fluoroscopic image T (x, y) generated from the point S2 by the second imaging match, the first Rotational imaging is restarted for the imaging function 301a of 1. The predetermined time ta is the time required for the imaging device 10 to start the rotational movement after the first imaging function 301a instructs the imaging device 10 to start the rotational movement. The predetermined time ta is, for example, 0.2 sec. Hereinafter, a specific determination method will be described.

(Explanation of method for predicting the position of contrast medium)
When the image pickup apparatus 10 is at a position corresponding to a time ta before a predetermined time ta from the point S2, at the same time based on the projected image I (x, y) generated by the first image pickup function 301a by rotation imaging. , The method of generating the reference image R (x, y, ω3) predicted to be generated by the image pickup apparatus 10 by the rotation imaging at the point S2 will be described. FIG. 4 is a diagram illustrating a method in which the X-ray diagnostic apparatus 1 according to the first embodiment generates a reference image.

The first restart instruction function 304a is a subject in the projected image I (x, y) generated by the first imaging at a position corresponding to a time before a predetermined time ta from the point S2 (first position). Based on the position of the contrast medium injected into P, the predicted position of the contrast medium before a predetermined time ta in the image generated by the first imaging from the point S2 is calculated. That is, the first restart instruction function 304a is a projection image generated by the first imaging function 301a rotating and imaging the time (t-ta) from a direction of a rotation angle (ω3-Δω) different from the point S2. Based on the position of the contrast medium injected into the subject P at I (x, y, ω3-Δω), the first imaging function 301a rotates and images at the point S2 at the same time (t-ta). The position of the contrast medium in the generated projected image I (x, y, ω3) is predicted. The angle Δω is an angle at which the image pickup apparatus 10 rotating at a steady speed v rotates during a predetermined time ta. For example, when ta = 0.2 sec and v = 25 deg / sec, Δω = 4 deg.

The first restart instruction function 304a reads out the projected image I (x, y, ω3-Δω) stored in the image memory 22. As shown in FIG. 4, the projected image I (x, y, ω3-Δω) shows the blood vessel 70 of interest in the subject P. A contrast medium is injected into the blood vessel 70 of interest, and a difference in brightness occurs in the portion where the contrast medium is injected with respect to other regions of the blood vessel. Here, the line segment connecting the X-ray tube 11 and the tip position Ra of the contrast medium is referred to as a line segment La.

The projected image I (x, y, ω3-Δω) may not be generated depending on the timing at which the first imaging function 301a performs imaging. In such a case, the first restart instruction function 304a reads out two projected images I (x, y) as close as possible to the rotation angle ω3 from the image memory 22. Then, the projected image I (x, y, ω3-Δω) is generated based on the two projected images I (x, y) read out. Specifically, by interpolating or extrapolating the two projected images I (x, y), the projected images I (x, y, ω3-) at the position corresponding to the rotation angle ω3-Δω Δω) is generated. Interpolation and extrapolation are performed by a known morphing process, which is a technique for deforming an image.

The tip position Ra of the contrast medium in the projected image I (x, y, ω3-Δω) was observed particularly darkly by the contrast medium from the region showing the blood vessel 70 of interest detected by image processing such as edge detection, for example. It can be identified by detecting the end points of the region (the region where the concentration of the contrast medium is high).

The first restart instruction function 304a virtually calculates a projected image Lb obtained by projecting the line segment La onto the projected image I (x, y, ω3) already generated by the first imaging function 301a. This projection is calculated by projecting a line segment La formulated as a spatial straight line onto a projection plane placed at a position corresponding to Δω. This projected image Lb is called an epipolar line. In the projected image I (x, y, ω3), the tip position of the contrast medium at time (t-ta) is on the epipolar line, that is, on the projected image Lb. Note that FIG. 4 is drawn larger than the actual Δω for the sake of clarity.

The first restart instruction function 304a obtains the intersection Rb of the blood vessel 70 of interest reflected in the projected image I (x, y, ω3) and the projected image Lb. This intersection Rb is the predicted position of the contrast medium observed from the direction of the rotation angle ω3 at the same time (t-ta) when the imaging device 10 is at the position of the rotation angle ω3-Δω at the time (t-ta). Is. Since the time when the projected image I (x, y, ω3-Δω) is generated and the time when the projected image I (x, y, ω3) is generated are different, as shown in FIG. 4, the intersection point Rb The position and the tip position Rc of the contrast medium in the projected image I (x, y, ω3) are generally different.

The first restart instruction function 304a stores the projected image I (x, y, ω3) in which the predicted position of the contrast medium, that is, the position of the intersection Rb is marked. The image in which the position of the intersection Rb is marked is referred to as a reference image R (x, y, ω3).

In this way, the first restart instruction function 304a is a reference image in which the imaging timing and the observation direction are both matched from the projected image I (x, y, ω3-Δω) in which the imaging timing is correct but the observation direction is different. Generate R (x, y, ω3).

The first restart instruction function 304a is the perspective image T generated by the second imaging function 301b at the generated reference image R (x, y, ω3) and the point S2 (ω = ω3). Compare with (x, y, ω3). Then, on condition that the position of the tip of the contrast medium in the fluoroscopic image T (x, y, ω3) and the position of the intersection Rb in the reference image R (x, y, ω3) match, the first imaging function 301a Is instructed to restart the rotation imaging.

The first restart instruction function 304a detects the tip position of the contrast medium from the fluoroscopic image T (x, y, ω3) by image processing. This process can be performed by known image processing. For example, edge detection is performed from the fluoroscopic image T (x, y, ω3) to detect the blood vessel 70 of interest. After that, the detected edge constituent points are expanded or the like to generate a region showing the blood vessel 70 of interest. Further, from the region showing the generated blood vessel 70 of interest, a point where the brightness is significantly different from that of the adjacent pixel may be detected and used as the tip position of the contrast medium.

(Explanation of how to generate a reconstructed image)
Before resuming rotational imaging, the position and orientation of the subject P that has moved due to body movement or the like is adjusted, but the position and orientation of the subject P may not completely match. When the positions and orientations of the subject P do not completely match in this way, a gap occurs between the projected image I1 (x, y) of the first cut and the projected image I2 (x, y) of the second cut. The deviation calculation function 309 calculates this deviation.

The deviation between the projected image I1 (x, y) of the first cut and the projected image I2 (x, y) of the second cut represents translation, rotation, and scaling between the two images, which is generally well known. It is described by a matrix representing the obtained affine transformation. The deviation calculation function 307 specifies a matrix representing this affine transformation. First, the deviation calculation function 309 sets the projected image captured last of the projected image I1 (x, y) of the first cut and the projected image first captured of the projected image I2 (x, y) of the second cut. Compare. Then, the deviation calculation function 309 selects a pair of corresponding points, that is, points representing the same information from the projected image I1 (x, y) of the first cut and the projected image I2 (x, y) of the second cut. Identify.

Specifically, the deviation calculation function 309 specifies the distribution of the pixel values of the pixels (x, y) of the projected image I1 (x, y) of the first cut and the pixels around the pixels. Then, a pixel having a pixel value distribution having a high correlation with the specified pixel value distribution is searched from the projected image I2 (x, y) of the second cut. Such a search for a corresponding point is performed, for example, by observing an object with two cameras and measuring the distance to the object, that is, a corresponding point from two images captured by a so-called stereo camera. Since it is a technique that is generally used when searching for the above, detailed description thereof will be omitted.

The deviation calculation function 309 searches for a plurality of such corresponding pixel pairs. Then, the deviation calculation function 309 substitutes the coordinate values of the corresponding pixels into a matrix representing the affine transformation to obtain simultaneous equations. Then, the deviation calculation function 309 specifies a matrix representing the affine transformation by solving this simultaneous equation. The more pairs of coordinate values of the corresponding pixels are used, the more accurately the matrix representing the affine transformation can be calculated.

The reconstruction function 308 uses a matrix representing the affine transformation specified by the deviation calculation function 309 to affine the projected image I1 (x, y) of the first cut or the projected image I2 (x, y) of the second cut. Convert. As a result, the projected image I1 (x, y) of the first cut and the projected image I2 (x, y) of the second cut are converted into a projected image without deviation.

It should be noted that the deviation may be corrected by either the projected image I1 (x, y) of the first cut or the projected image I2 (x, y) of the second cut. However, in order to reduce the calculation load as much as possible, it is desirable to correct the deviation for the projected image of the cut in which the number of images is small.

Subsequently, the reconstruction function 308 uses the projection image I1 (x, y) of the first cut and the projection image I2 (x) of the second cut with the deviation corrected for the three-dimensional reconstruction circuit 26 (FIG. 1). , Y), and instruct the generation of the reconstruction data (volume data) of the subject P. The reconstruction data may be generated by a known method. Detailed explanation will be omitted.

(Explanation of the flow of rotational imaging performed by the X-ray diagnostic device)
FIG. 5 is a diagram illustrating an outline of a flow of rotational imaging performed by the X-ray diagnostic apparatus 1 according to the first embodiment. Note that FIG. 5 shows how the rotation angle ω of the imaging device 10 changes with time t, with the horizontal axis representing the rotation angle ω of the imaging device 10 and the vertical axis representing the time t.

The image pickup apparatus 10 is at the position of the point S0 at which the rotational movement is started in order to perform the rotary imaging at the time t0.

According to the instruction of the first imaging function 301a, the imaging device 10 starts rotational movement at time t0. After that, the image pickup apparatus 10 accelerates and reaches a steady velocity v at the point S1 at the rotation angle ω1 at time t1. Then, the first imaging function 301a starts rotational imaging (first imaging) from the position of the point S1 to generate the projected image I1 (x, y) of the first cut.

After that, at time t2, it is assumed that the imaging is interrupted at the point Q at the rotation angle ω2.

At this time, the first movement function 302a calculates the point S2 at which the image pickup apparatus 10 is moved in order to restart the rotation imaging. It is assumed that the point S2 (rotation angle ω3) is calculated at the time t3 and the image pickup apparatus 10 can be moved. The rotation angle ωa described above corresponds to ω2-ω3. At this time, the operator of the X-ray diagnostic apparatus 1 restores the position and orientation of the subject P that has moved due to body movement or the like.

The first movement function 302a gives an instruction to the movement control circuit 24 at time t3 to move the image pickup apparatus 10 to the point S2.

The image pickup apparatus 10 reaches the point S2 at time t4.

The first restart instruction function 304a generates a reference image R (x, y, ω3) based on the projected image rotationally imaged at the point S2.

After the first restart instruction function 304a generates the reference image R (x, y, ω3), the second imaging function 301b starts fluoroscopy at the point S2 at time t5.

The first restart instruction function 304a determines whether the fluoroscopic image T (x, y, ω3) captured by fluoroscopy matches the reference image R (x, y, ω3). Here, it is assumed that the first restart instruction function 304a determines that the perspective image T (x, y, ω3) and the reference image R (x, y, ω3) match at time t6.

The first restart instruction function 304a instructs the image pickup apparatus 10 to start the rotational movement at time t6.

The image pickup apparatus 10 starts rotational movement according to the instruction of the first restart instruction function 304a. Then, at time t7, the point Q at the rotation angle ω2 is reached, and the steady velocity v is reached. The first restart instruction function 304a causes the first image pickup function 301a to restart the rotation imaging from the position of the point Q. Then, the first imaging function 301a starts rotational imaging (first imaging) from the position of the point Q to generate the projected image I2 (x, y) of the second cut.

After that, the first imaging function 301a ends the rotation imaging on condition that the imaging device 10 reaches the preset point S3 (rotation angle ω4) at which the rotation imaging ends. The time when the rotation imaging is finished is time t8.

(Explanation of the processing flow performed by the X-ray diagnostic device)
Next, the flow of rotational imaging performed by the X-ray diagnostic apparatus 1 will be described step by step. FIG. 6 is a flowchart showing an example of the procedure of rotation imaging performed by the X-ray diagnostic apparatus 1 according to the first embodiment.

The first imaging function 301a instructs the injector 60 to inject the contrast medium (step S1).

The first imaging function 301a starts rotary imaging (step S2).

The first imaging function 301a determines whether the interrupt button has been operated (step S3). When it is determined that the interrupt button has been operated (step S3: Yes), the process proceeds to step S4. On the other hand, if it is not determined that the interrupt button has been operated (step S3: No), the process proceeds to step S14.

When it is determined that the interrupt button has been operated in step S3, the first movement function 302a calculates the point S2 (step S4).

On the other hand, if it is not determined in step S3 that the interrupt button has been operated, the first imaging function 301a determines whether the imaging device 10 has reached the end point of the rotation imaging (step S14). When it is determined that the image pickup apparatus 10 has reached the end point of the rotation imaging (step S14: Yes), the X-ray diagnostic apparatus 1 ends the process of FIG. On the other hand, if it is not determined whether the image pickup apparatus 10 has reached the end point of the rotation imaging (step S14: No), the process returns to step S2 and the rotation imaging is continued.

Following step S4, the first movement function 302a moves the image pickup apparatus 10 to the point S2 (step S5).

The second imaging function 301b generates a reference image R (x, y, ω3) (step S6).

The first imaging function 301a instructs the injector 60 to inject a contrast medium (step S7).

The second imaging function 301b executes fluoroscopy (step S8).

The first restart instruction function 304a determines whether the perspective image T (x, y, ω3) and the reference image R (x, y, ω3) match (step S9). When it is determined that the fluoroscopic image T (x, y, ω3) and the reference image R (x, y, ω3) match (step S9: Yes), the process proceeds to step S10. On the other hand, if it is not determined that the perspective image T (x, y, ω3) and the reference image R (x, y, ω3) match (step S9: No), the process returns to step S8.

When it is determined in step S9 that the perspective image T (x, y, ω3) and the reference image R (x, y, ω3) match, the first restart instruction function 304a refers to the movement control circuit 24. , The rotational movement of the image pickup apparatus 10 is restarted (step S10).

The first moving function 302a determines whether the imaging device 10 has reached the position where the rotation imaging is interrupted (step S11). When it is determined that the image pickup apparatus 10 has reached the position where the rotation imaging is interrupted (step S11: Yes), the process proceeds to step S12. On the other hand, if it is not determined that the imaging device 10 has reached the position where the rotation imaging is interrupted (step S11: No), the determination in step S11 is repeated.

In step S11, when the first moving function 302a determines that the imaging device 10 has reached the position where the rotation imaging is interrupted, the first imaging function 301a restarts the rotation imaging (step S12).

The first imaging function 301a determines whether the imaging device 10 has reached the end position of the rotation imaging (step S13). When it is determined that the image pickup apparatus 10 has reached the end position of the rotation imaging (step S13: Yes), the X-ray diagnostic apparatus 1 ends the process of FIG. On the other hand, if it is not determined that the image pickup apparatus 10 has reached the end position of the rotation imaging (step S13: No), the process returns to step S12 and the rotation imaging is continued.

Although not described in the flowchart of FIG. 6, when the interrupt button is operated after restarting the rotation imaging in step S12, the processes from step S4 to step S10 may be repeated.

As described above, in the X-ray diagnostic apparatus 1 of the embodiment, the first imaging function 301a (first imaging unit) provides an X-ray tube 11 (X-ray source) and a subject P to irradiate X-rays. An image pickup device 10 including an X-ray detector 12 having a plurality of pixels for detecting the intensity of transmitted X-rays is rotated around the subject P, and a first dose is applied to the X-ray tube 11. Rotational imaging (first imaging) is performed to generate a projected image I (x, y) (image) based on the intensity of X-rays transmitted through the subject P by irradiation. Then, when the rotation imaging is interrupted, the first movement function 302a (first moving unit) moves the imaging device 10 to the point S2 (first position) corresponding to the position where the rotation imaging is interrupted. Let me. The second imaging function 301b (second imaging unit) irradiates the X-ray tube 11 with X-rays having a second dose lower than the first dose at the point S2, and X-rays transmitted through the subject P. A second imaging is performed to generate a perspective image T (x, y, ω3) (projected image) based on the intensity of the line. The first restart instruction function 304a (first restart instruction unit) is provided on the condition that the fluoroscopic image T (x, y, ω3) generated by the second imaging is determined to satisfy a predetermined condition. The rotational movement of the imaging device 10 is restarted, and the first imaging function 301a restarts the rotational imaging on condition that the imaging device 10 reaches the position where the rotational imaging is interrupted. Therefore, the calculation of the position of the point S2 for moving the image pickup apparatus 10 after the interruption of the rotation imaging and the determination of the start of the rotation imaging are both performed in a short time by computer processing. Further, the fluoroscopy performed when determining the resumption of rotational imaging is performed in a state where the dose of X-rays to be irradiated is low. Therefore, it is possible to reduce the burden on the patient and the exposure dose when performing reimaging.

Further, in the X-ray diagnostic apparatus 1 of the embodiment, the first moving function 302a (first moving portion) is subjected to the first imaging by the imaging device 10 that has started rotational movement at the point S2 (first position). The position of the point S2 is determined so that the function 301a (first imaging unit) reaches a predetermined steady speed v at the position where the rotation imaging is interrupted. Therefore, the position at which the rotational movement of the image pickup apparatus 10 is restarted can be calculated by a simple calculation.

Further, in the X-ray diagnostic apparatus 1 of the embodiment, the first moving function 302a (first moving unit) is the time required from the start of rotation of the imaging device 10 to the steady speed v (acceleration time To). ) And the steady velocity v, the position of the point S2 is determined. Therefore, the position where the image pickup apparatus 10 resumes the rotational movement can be calculated by a simple calculation.

Further, in the X-ray diagnostic apparatus 1 of the embodiment, the predetermined condition is the projected image I (1st position) generated by the first imaging at a position corresponding to a time ta before a predetermined time ta from the point S2 (first position). The predicted position of the contrast medium injected into the subject P at x, y) at the point S2 and the position of the contrast medium at the fluoroscopic image T (x, y) generated by the second imaging from the point S2 are To match. Therefore, the timing for resuming the rotational movement of the imaging device 10 can be accurately determined based on the position of the contrast medium injected into the subject P.

Further, in the X-ray diagnostic apparatus 1 of the embodiment, the first restart instruction function 304a is a projection image I (x, y, ω3) generated by the first imaging at the point S2 (first position). The predicted position of the contrast medium injected into the subject P before the predetermined time ta is obtained by the following method. That is, the first restart instruction function 304a is the subject in the projected image I (x, y, ω3-Δω) generated by the first imaging at the position corresponding to the time before the predetermined time ta from the point S2. An epipolar line indicating the tip position of the contrast medium injected into the blood vessel 70 of interest in P is obtained. Then, the obtained epipolar line is projected from the direction of the point S2 onto the projected image I (x, y, ω3) generated by the first imaging to generate the projected image Lb, and the projected image I (x, y, ω3) is generated. The predicted position of the contrast agent is calculated as the intersection of the projected image Lb in ω3) and the blood vessel 70 of interest. Therefore, the position of the contrast medium can be accurately predicted by a simple arithmetic process based on the actually captured projected image I (x, y, ω3-Δω).

Further, in the X-ray diagnostic apparatus 1 of the embodiment, after the first imaging function 301a (first imaging unit) instructs the imaging apparatus 10 to start the rotational movement, the imaging apparatus 10 sets the predetermined time ta. This is the time required to start the rotational movement. Therefore, the timing at which the image pickup apparatus 10 restarts the rotational movement can be accurately determined in consideration of the operating time of the X-ray diagnostic apparatus 1.

Further, in the X-ray diagnostic apparatus 1 of the embodiment, the deviation calculation function 309 (deviation calculation unit) is generated by the first imaging function 301a (first imaging unit) by the rotation imaging before the interruption of the rotation imaging. One-cut projected image I1 (x, y) and second-cut projected image I2 (x, y) generated by the first imaging function 301a (first imaging unit) by rotational imaging after resuming rotational imaging. Calculate the deviation. Then, the reconstruction function 308 (reconstruction unit) determines the projection image I1 (x, y) of the first cut or the projection image I2 (x, y) of the second cut based on the deviation calculated by the deviation calculation function 309. ) Is corrected, and a reconstructed image of the cross section of the subject P is generated. Therefore, even when reimaging is performed, the reconstructed image can be reliably generated.

(Second Embodiment)
Next, the X-ray diagnostic apparatus 2 according to the second embodiment will be described. The X-ray diagnostic apparatus 2 sets a position at which the imaging apparatus 10 is moved in order to restart the rotational imaging when the rotational imaging is interrupted in the middle of the X-ray diagnostic apparatus 1 described in the first embodiment. The position does not depend on the position where the rotation imaging is interrupted. For example, the X-ray diagnostic apparatus 2 moves the imaging device 10 in which the rotational imaging is interrupted when the rotational imaging is performed without injecting the contrast medium, or when the injection timing of the contrast medium by the injector 60 and the rotational imaging are linked. The tip is a position that does not depend on the position where the rotation imaging is interrupted. The X-ray diagnostic apparatus 2 includes a processing circuit 30b (FIG. 7) instead of the processing circuit 30a with respect to the X-ray diagnostic apparatus 1 (FIG. 1). Since the components other than the processing circuit 30b are the same as those of the X-ray diagnostic apparatus 1, the same reference numerals as those used in the first embodiment will be used for description.

(Explanation of functional configuration of processing circuit)
FIG. 7 is a block diagram showing a configuration example of the processing circuit 30b of the X-ray diagnostic apparatus 2 according to the second embodiment.

The processing circuit 30b executes the first imaging function 301a, the second moving function 302b, the second restart instruction function 304b, the reconstruction function 308, the deviation calculation function 309, and the display control function 310. ..

Of these, the first imaging function 301a, the reconstruction function 308, the deviation calculation function 309, and the display control function 310 are functions executed by the processing circuit 30a of the X-ray diagnostic apparatus 1 described in the first embodiment. Is similar to. Therefore, the description of these functions will be omitted.

The second movement function 302b moves the image pickup device 10 to a second position regardless of the position where the rotation image pickup is interrupted when the image pickup device 10 interrupts the rotation imaging. The second moving function 302b is an example of the second moving unit.

The second restart instruction function 304b rotates and moves the image pickup device 10 from the second position in a state where the X-ray tube 11 is not irradiated with X-rays, and the image pickup device 10 reaches the position where the rotation image pickup is interrupted. On condition that this is done, the first imaging function 301a restarts the rotation imaging. The second restart instruction function 304b is an example of the second restart instruction unit.

(Explanation of rotation imaging operation)
FIG. 8 is a diagram illustrating a rotation imaging performed by the X-ray diagnostic apparatus 2 according to the second embodiment. The imaging device 10 starts rotational movement from the point S0 (ω = ω0), starts rotational imaging from the point S1 (ω = ω1) that has reached a predetermined steady speed v, and performs imaging of the first cut (movement). Trajectory M5). When the patient (subject P) moves during the rotary imaging of the first cut, the imaging device 10 receives an instruction from a doctor or the like and at a position where the movement of the patient is confirmed (for example, point Q (ω = ω2)). The rotation imaging is interrupted. That is, the projected image I1 (x, y) of the first cut from the point S1 to the point Q is imaged.

When the rotation imaging is interrupted, as shown in FIG. 8, the imaging device 10 is instructed by the second movement function 302b to reach the point S0 (ω = ω0), that is, the second position regardless of the position where the rotation imaging is interrupted. (Movement locus M6).

After that, the image pickup apparatus 10 restarts the rotational movement from the point S0 according to the instruction of the second restart instruction function 304b.

The imaging device 10 that has resumed rotational movement reaches a steady velocity v at point S1 (ω = ω1). After that, it moves to the point Q (ω = ω2) where the imaging of the first cut is interrupted without irradiating X-rays and without performing rotational imaging (movement locus M7).

When the second restart instruction function 304b detects that the imaging device 10 has reached the point Q, the second restart instruction function 304b starts imaging of the projected image I2 (x, y) of the second cut.

After that, the image pickup apparatus 10 continues to capture the projected image I2 (x, y) of the second cut until it reaches the predetermined point S3 (ω = ω4) (movement locus M8).

(Explanation of the flow of rotational imaging performed by the X-ray diagnostic device)
FIG. 9 is a diagram illustrating an outline of a flow of rotational imaging performed by the X-ray diagnostic apparatus 2 according to the second embodiment. Note that FIG. 9 shows how the rotation angle ω of the image pickup apparatus 10 changes with time t in the same format as in FIG. 5 described above.

The image pickup apparatus 10 is at the position of the point S0 at which the rotation starts to perform the rotation imaging at the time t0.

According to the instruction of the first imaging function 301a, the imaging device 10 starts rotating at time t0. After that, the image pickup apparatus 10 accelerates and reaches a steady velocity v at the point S1 at the rotation angle ω1 at time t1. Then, the first imaging function 301a starts rotational imaging (first imaging) from the position of the point S1 to generate the projected image I1 (x, y) of the first cut.

After that, at time t2, at the point Q at the rotation angle ω2, it is assumed that the rotation imaging is interrupted.

Then, after returning the position of the subject P to its original position, the second movement function 302b instructs the movement control circuit 24 to move the image pickup device 10 to the point S0 (second position) at time t3. Is issued.

The image pickup apparatus 10 reaches the point S0 at time t4.

The second restart instruction function 304b instructs the image pickup apparatus 10 to start the rotational movement at time t4. In FIG. 9, it is assumed that the image pickup device 10 that has moved to the point S0 immediately starts rotational movement at the time t4, but after the image pickup device 10 is made to stand by at the point S0, the device drive button or the like is used. Rotational movement may be started based on the instruction.

By the action of the first imaging function 301a, the imaging device 10 starts rotating. Then, at time t5, the point S1 at the rotation angle ω1 is reached, and the steady velocity v is reached. The first imaging function 301a continues to rotate and move the imaging device 10 at a steady speed v without irradiating X-rays from the X-ray tube 11.

After that, the image pickup apparatus 10 reaches the point Q at the rotation angle ω2 at time t6.

At the point Q, the second restart instruction function 304b starts the irradiation of X-rays from the X-ray tube 11 to the first image pickup function 301a to restart the rotation imaging. Then, the first imaging function 301a generates the projected image I2 (x, y) of the second cut.

After that, the first imaging function 301a ends the rotation imaging on condition that the imaging device 10 reaches the preset point S3 (rotation angle ω4) at which the rotation imaging ends. The time when the rotation imaging is finished is time t7.

(Explanation of the processing flow performed by the X-ray diagnostic device)
FIG. 10 is a flowchart showing an example of the procedure of rotation imaging performed by the X-ray diagnostic apparatus 2 according to the second embodiment.

The first imaging function 301a instructs the injector 60 to inject the contrast medium (step S21).

The first imaging function 301a starts rotary imaging (step S22).

The first imaging function 301a determines whether the interrupt button has been operated (step S23). When it is determined that the interrupt button has been operated (step S23: Yes), the process proceeds to step S24. On the other hand, if it is not determined that the interrupt button has been operated (step S23: No), the process proceeds to step S30.

When it is determined in step S23 that the interrupt button has been operated, the second movement function 302b moves the image pickup apparatus 10 to the point S0 (step S24).

On the other hand, if it is not determined in step S23 that the interrupt button has been operated, the first imaging function 301a determines whether the imaging device 10 has reached the end point of the rotation imaging (step S30). When it is determined that the image pickup apparatus 10 has reached the end point of the rotation imaging (step S30: Yes), the X-ray diagnostic apparatus 2 ends the process of FIG. On the other hand, if it is not determined that the image pickup apparatus 10 has reached the end point of the rotation imaging (step S30: No), the process returns to step S22 and the rotation imaging is continued.

Following step S24, the second restart instruction function 304b causes the movement control circuit 24 to restart the rotational movement of the image pickup apparatus 10 (step S25).

Then, the first imaging function 301a instructs the injector 60 to inject the contrast medium (step S26).

The second restart instruction function 304b determines whether the imaging device 10 has reached the position (point Q) where the rotation imaging is interrupted (step S27). When it is determined that the image pickup apparatus 10 has reached the position where the rotation imaging is interrupted (step S27: Yes), the process proceeds to step S28. On the other hand, if it is not determined that the imaging device 10 has reached the position where the rotation imaging is interrupted (step S27: No), the determination in step S27 is repeated.

When it is determined in step S27 that the imaging device 10 has reached the position where the rotation imaging is interrupted, the first imaging function 301a restarts the rotation imaging (step S28).

The first imaging function 301a determines whether the imaging device 10 has reached the end position of the rotation imaging (step S29). When it is determined that the image pickup apparatus 10 has reached the end position of the rotation imaging (step S29: Yes), the X-ray diagnostic apparatus 2 ends the process of FIG. On the other hand, if it is not determined that the image pickup apparatus 10 has reached the end position of the rotation imaging (step S29: No), the process returns to step S28 and the rotation imaging is continued.

Although not described in the flowchart of FIG. 10, when the interrupt button is operated after restarting the rotation imaging in step S28, the processes from step S24 to step S28 may be repeated.

In the above description, when the rotation imaging is interrupted, the second moving function 302b moves the imaging device 10 to the point S0, but the second moving function 302b moves the imaging device 10. The position is not limited to the point S0. That is, when the rotation of the imaging device 10 is restarted at the position where the projected image I1 (x, y) of the first cut is imaged, the speed of the imaging device 10 interrupts the rotation imaging Q. The position where the steady velocity v is reached can be set as the point S0.

(Modified example of the second embodiment)
Next, a modified example of the second embodiment will be described. In the modified example of the second embodiment, when the rotation imaging is interrupted in the middle, the position where the imaging device 10 is moved in order to restart the rotation imaging is selected according to the diagnostic conditions such as the injection method of the contrast medium. This is an example of an X-ray diagnostic apparatus 2a having a function.

FIG. 11 is a block diagram showing a configuration example of the processing circuit 30c of the X-ray diagnostic apparatus 2a according to the modified example of the second embodiment.

The processing circuit 30c includes a first imaging function 301a, a first moving function 302a, a second moving function 302b, a second imaging function 301b, a first restart instruction function 304a, and a second restart. The instruction function 304b, the reimaging method selection function 305, the reconstruction function 308, the deviation calculation function 309, and the display control function 310 are executed.

Of these, the functions other than the reimaging method selection function 305 are as described in the first embodiment and the second embodiment, and thus the description thereof will be omitted.

The reimaging method selection function 305 places the imaging device 10 at either the above-mentioned point S2 (FIG. 3) or the first position or the point S0 (FIG. 8) or the second position when the rotation imaging is interrupted. Select whether to move to. Specifically, the reimaging method selection function 305 tells the operator of the X-ray diagnostic apparatus 2a that the imaging apparatus 10 is placed in the first position or the second position when the rotation imaging is interrupted before starting the diagnosis. The input interface 50 may be used to select which position to move. The reimaging method selection function 305 is an example of a selection unit.

For example, when the timing of injecting the contrast medium is manually instructed, the moving destination of the imaging device 10 in which the rotation imaging is interrupted may be set to the first position. Further, when rotational imaging is performed without injecting the contrast medium, or when the rotational imaging and the injection of the contrast medium by the injector 60 are linked, the moving destination of the imaging device 10 in which the rotational imaging is interrupted is set as the second position. Just do it.

(Explanation of the processing flow performed by the X-ray diagnostic device)
The X-ray diagnostic apparatus 2a performs processing according to the movement destination of the imaging apparatus 10 selected by the reimaging method selection function 305. That is, when the reimaging method selection function 305 selects to move the imaging device 10 to the point S2 (first position) when the rotation imaging is interrupted, the process according to the flowchart of FIG. 6 is performed. When the reimaging method selection function 305 selects to move the imaging device 10 to the point S0 (second position) when the rotation imaging is interrupted, the process according to the flowchart of FIG. 10 is performed.

As described above, in the X-ray diagnostic apparatus 2 of the second embodiment, the first imaging function 301a (first imaging unit) is covered with the X-ray tube 11 (X-ray source) that irradiates X-rays. An imaging device 10 including an X-ray detector 12 having a plurality of pixels for detecting the intensity of X-rays transmitted through the sample P is rotated around the subject P, and the first X-ray tube 11 is connected. Rotational imaging (first imaging) is performed to generate a projected image I (x, y) (image) based on the intensity of X-rays transmitted through the subject P by irradiating the dose of. Then, when the rotational imaging is interrupted, the second moving function 302b (second moving unit) causes the imaging device 10 to move to the point S0 (second position) regardless of the position where the first imaging is interrupted. ). Then, the second restart instruction function 304b (second restart instruction unit) rotates and moves the image pickup device 10 from the point S0 in a state where the X-ray tube 11 is not irradiated with X-rays, and the image pickup device 10 causes the image pickup device 10 to rotate. The first imaging function 301a restarts the rotation imaging on condition that the position where the rotation imaging is interrupted is reached. Therefore, it is possible to reduce the burden on the patient and the exposure dose when performing reimaging.

Further, in the X-ray diagnostic apparatus 2a of the modified example of the second embodiment, when the reimaging method selection function 305 (selection unit) interrupts the rotational imaging of the imaging apparatus 10, the imaging apparatus 10 is subjected to rotational imaging. It is selected whether to move to the point S2 (first position) according to the interrupted position or the point S0 (second position) not dependent on the interrupted position of the rotation imaging. Then, when the rotation imaging is interrupted, the X-ray diagnostic apparatus 2a performs reimaging according to the result selected by the reimaging method selection function 305. Therefore, it is possible to select an imaging method with a smaller exposure amount according to the diagnostic conditions such as the injection method of the contrast medium and the use / non-use of the contrast medium.

(Third Embodiment)
Next, the X-ray diagnostic apparatus 3 according to the third embodiment will be described. The X-ray diagnostic apparatus 3 performs reimaging on the X-ray diagnostic apparatus 1 described in the first embodiment with respect to the range from the designated reimaging start point to the reimaging end point after the rotation imaging is completed. It has a function to do. The X-ray diagnostic apparatus 3 includes a processing circuit 30d (FIG. 12) instead of the processing circuit 30a with respect to the X-ray diagnostic apparatus 1 (FIG. 1). Since the components other than the processing circuit 30d are the same as those of the X-ray diagnostic apparatus 1, the same reference numerals as those used in the first embodiment will be used for description.

(Explanation of functional configuration of processing circuit)
FIG. 12 is a block diagram showing a configuration example of the processing circuit 30d of the X-ray diagnostic apparatus 3 according to the third embodiment.

The processing circuit 30d is reconfigured with a first imaging function 301a, a first moving function 302a, a second imaging function 301b, a first restart instruction function 304a, and a reimaging start / end position instruction function 306. The function 308, the deviation calculation function 309, and the display control function 310 are executed.

Of these, the functions other than the reimaging start / end position indicating function 306 are as described in the first embodiment, and thus the description thereof will be omitted.

The reimaging start / end position indicating function 306 is a start position at which the first imaging function 301a causes the first imaging to be performed again from the projection images I1 (x, y) of the first cut generated by the rotation imaging. Instruct the end position. The reimaging start / end position indicating function 306 is an example of the start / end position indicating unit. Specifically, the reimaging start / ending position indicating function 306 causes the display control function 310 to display the projected image I1 (x, y) of the first cut, which has been rotationally imaged, on the display 40, and the X-ray diagnostic apparatus 3 The operator is instructed by the input interface 50 to indicate the corresponding image.

After the rotation imaging is completed, the X-ray diagnostic apparatus 3 performs rotation imaging again between the start position and the end position of the reimaging indicated by the reimaging start / end position indicating function 306, and the imaging apparatus 10 is made to image the projected image I2 (x, y) of the second cut. At that time, the first moving function 302a reads out the rotation angle ω given as incidental information to the projected image I1 (x, y) indicating the designated reimaging start position. Then, the first movement function 302a calculates a rotation start position so that the image pickup device 10 that rotates and moves for rotation imaging has a steady speed v at the position of the rotation angle ω. This rotation start position corresponds to the point S2 (first position) described in the first embodiment. Then, the first movement function 302a moves the image pickup apparatus 10 to the point S2. After that, as described in the first embodiment, the first restart instruction function 304a determines the timing at which the rotational movement of the image pickup apparatus 10 is started. Then, when it is determined that it is time to start the rotational movement, the rotational imaging is started. This rotation imaging is performed until the imaging device 10 reaches the end position of the reimaging.

(Explanation of the processing flow performed by the X-ray diagnostic device)
FIG. 13 is a flowchart showing an example of the procedure of rotation imaging performed by the X-ray diagnostic apparatus 3 according to the third embodiment. In particular, FIG. 13 is a flowchart illustrating a flow of processing for performing reimaging in the range between the designated reimaging start point and the reimaging end point after the X-ray diagnostic apparatus 3 finishes the rotation imaging. is there.

The reimaging start / end position indicating function 306 (start / end position indicating unit) re-images the projected images I (x, y) captured by the first imaging function 301a (first imaging unit) by rotary imaging. A reimaging start point for starting imaging is specified (step S40).

Next, the reimaging start / end position indicating function 306 (start / end position indicating unit) is included in the projected image I (x, y) imaged by the first imaging function 301a (first imaging unit) by rotation imaging. Therefore, the reimaging end point at which the reimaging is finished is specified (step S41).

Since the next processes from step S42 to step S48 are the same as the processes described in the first embodiment (steps S4 to S10 in FIG. 6), the description thereof will be omitted.

Following step S48, the first moving function 302a determines whether the imaging device 10 has reached the reimaging start point (step S49). When it is determined that the image pickup apparatus 10 has reached the reimaging start point (step S49: Yes), the process proceeds to step S50. On the other hand, if it is not determined that the image pickup apparatus 10 has reached the reimaging start point (step S49: No), the determination in step S49 is repeated.

When it is determined in step S49 that the imaging device 10 has reached the reimaging start point, the first imaging function 301a starts rotary imaging (step S50).

The first imaging function 301a determines whether the imaging device 10 has reached the reimaging end point (step S51). When it is determined that the image pickup apparatus 10 has reached the reimaging end point (step S51: Yes), the X-ray diagnostic apparatus 3 ends the process of FIG. On the other hand, if it is not determined that the imaging device 10 has reached the reimaging end point (step S51: No), the process returns to step S50 and the rotation imaging is continued.

As described above, in the X-ray diagnostic apparatus 3 of the third embodiment, the reimaging start / end position indicating function 306 (start / end position indicating unit) and the first imaging function 301a (first imaging unit) are used. From the projected images I (x, y) generated by the rotation imaging, the reimaging start point for restarting the first imaging and the reimaging end point for ending the reimaging are specified. Then, the first moving function 302a (first moving unit) moves the image pickup apparatus 10 to the point S2 (first position) corresponding to the re-imaging start point. The second imaging function 301b (second imaging unit) irradiates the X-ray tube 11 with X-rays having a second dose lower than the first dose at the point S2, and the fluoroscopic image T (x, y). , Ω3) (projected image) is imaged. The first restart instruction function 304a (first restart instruction unit) is conditioned on the condition that the fluoroscopic image T (x, y, ω3) captured by the second imaging function 301b is determined to satisfy a predetermined condition. As a result, the rotational movement of the imaging device 10 is restarted, and the first imaging function 301a terminates the rotational imaging on condition that the imaging device 10 reaches the reimaging end point. Therefore, when it becomes necessary to re-image the projected image I (x, y) generated by the rotation imaging, it is not necessary to re-image the entire image, and only the angle range in which the re-imaging is necessary is accurately re-imaged. can do.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention as well as the invention described in the claims and the equivalent scope thereof.

1,2,2a, 3 X-ray diagnostic equipment
10 Imaging device
11 X-ray tube (X-ray source)
12 X-ray detector
301a First imaging function (first imaging unit)
301b Second imaging function (second imaging unit)
302a First movement function (first movement part)
302b Second movement function (second movement part)
304a First restart instruction function (first restart instruction unit)
304b Second restart instruction function (second restart instruction unit)
305 Reimaging method selection function (selection unit)
306 Reimaging start / end position indication function (start / end position indication unit)
308 Reconstruction function (reconstruction unit)
309 Deviation calculation function (deviation calculation unit)
310 Display control function
S2 point (first position)
Point S0 (second position)
I (x, y) Projection image I1 (x, y) Projection image of the first cut I2 (x, y) Projection image of the second cut R (x, y, ω3) Reference image T (x, y, ω3) Perspective image

Claims (9)

While rotating an imaging device including an X-ray source for irradiating X-rays and an X-ray detector having a plurality of pixels for detecting the intensity of X-rays transmitted through the subject, around the subject. A first imaging unit that irradiates the X-ray source with a first dose and performs a first imaging to generate an image based on the intensity of the X-ray transmitted through the subject.
When the first imaging is interrupted, the first moving unit that moves the imaging device to the first position according to the position where the first imaging is interrupted, and
At the first position, the X-ray source is irradiated with a second dose lower than the first dose, and a second imaging is performed to generate an image based on the intensity of the X-ray transmitted through the subject. The second imaging unit to be performed and
On condition that the image generated by the second imaging satisfies a predetermined condition, the rotational movement of the imaging device is restarted, and the imaging device is placed at a position where the first imaging is interrupted. A first restart instruction unit that causes the first image pickup unit to restart the first image pickup on condition that the image has been reached.
An X-ray diagnostic device comprising. The first moving unit determines the first position so that the imaging device that has started rotational movement at the first position reaches a steady speed at a position where rotational imaging is interrupted.
The X-ray diagnostic apparatus according to claim 1. The first moving unit determines the first position based on the time required from the start of the rotational movement of the imaging device to the steady-state speed and the steady-state speed.
The X-ray diagnostic apparatus according to claim 2. The predetermined conditions are
A predicted position at the first position of the contrast medium injected into the subject in the image generated by the first imaging at a position corresponding to a time predetermined time before the first position.
The position of the contrast medium in the image generated by the second imaging at the first position coincides with that of the image.
The X-ray diagnostic apparatus according to any one of claims 1 to 3. The predetermined time is the time required for the imaging device to start the rotational movement after the first imaging unit instructs the imaging device to start the rotational movement.
The X-ray diagnostic apparatus according to claim 4. While rotating an imaging device including an X-ray source for irradiating X-rays and an X-ray detector having a plurality of pixels for detecting the intensity of X-rays transmitted through the subject, around the subject. A first imaging unit that irradiates the X-ray source with a first dose and performs a first imaging to generate an image based on the intensity of the X-ray transmitted through the subject.
When the first imaging is interrupted, the image pickup apparatus is moved to a second position regardless of the position where the first imaging is interrupted, and a second moving unit.
The condition is that the imaging device is rotated and moved from the second position without irradiating the X-ray source with X-rays, and the imaging device reaches the position where the first imaging is interrupted. As a result, a second restart instruction unit that causes the first imaging unit to resume the first imaging, and
An X-ray diagnostic device comprising. When the first imaging is interrupted, the first moving unit that moves the imaging device to the first position according to the position where the first imaging is interrupted, and
At the first position, the X-ray source is irradiated with a second dose lower than the first dose, and a second imaging is performed to generate an image based on the intensity of the X-ray transmitted through the subject. The second imaging unit to be performed and
On condition that the image generated by the second imaging satisfies a predetermined condition, the rotational movement of the imaging device is restarted, and the imaging device is placed at a position where the first imaging is interrupted. A first restart instruction unit that causes the first image pickup unit to restart the first image pickup on condition that the image has been reached.
A selection unit that selects whether to move the imaging device to the first position or the second position when the first imaging is interrupted.
The X-ray diagnostic apparatus according to claim 6. Before the interruption of the first imaging, the image of the first cut generated by the first imaging unit by the first imaging, and after the resumption of the first imaging, the first imaging unit is the first. A deviation calculation unit that calculates the deviation from the image of the second cut generated by imaging, and
Based on the deviation calculated by the deviation calculation unit, the reconstruction unit that corrects the image of the first cut or the image of the second cut and generates a reconstruction image of the cross section of the subject.
The X-ray diagnostic apparatus according to any one of claims 1 to 7, further comprising. While rotating an imaging device including an X-ray source for irradiating X-rays and an X-ray detector having a plurality of pixels for detecting the intensity of X-rays transmitted through the subject, around the subject. A first imaging unit that irradiates the X-ray source with a first dose and performs a first imaging to generate an image based on the intensity of the X-ray transmitted through the subject.
From the images generated by the first imaging by the first imaging unit, a start / end position indicating unit that instructs a start position and an end position to perform the first imaging again, and
A first moving unit that moves the imaging device to a first position corresponding to the starting position, and
At the first position, the X-ray source is irradiated with a second dose lower than the first dose, and a second imaging is performed to generate an image based on the intensity of the X-ray transmitted through the subject. The second imaging unit to be performed and
On condition that the image generated by the second imaging satisfies a predetermined condition, the rotational movement of the imaging device is restarted, and the imaging device reaches the start position. A first restart instruction unit that causes the first image pickup unit to restart the first image pickup, and
An X-ray diagnostic device comprising.

Images