JPH06233752A - Digital x-ray radiographing system - Google Patents

Abstract

PURPOSE:To shorten the time required for radiographing an examinee by rotating an X-ray tube device and an X-ray detector around the examinee and to observe the condition of the examinee at all times. CONSTITUTION:A rotation controller 7 for controlling the rotating operation of a rotary supporter 1 controls this rotary supporter 1 so as to rotate it forward and backward between arbitrary angles, and a system controller 8 controls so as to enable radiographing by continuously radiating X rays from an X-ray tube device 2 throughout a period in which the rotary supporter 1 is rotated forward and backward and reversed in the forward and backward directions. Thus, the time required for all the radiographing can be shortened, and the condition of the examinee can always be observed during the entire radiographing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention radiates X-rays to a subject while rotating an X-ray tube device and an X-ray detector around the subject on a table to detect a transmitted X-ray image. The present invention relates to a digital X-ray imaging apparatus capable of X-ray imaging and observing a diagnostic region of the subject as a stereoscopic image, and in particular, the time required for imaging by rotating the X-ray tube device and the X-ray detector around the subject. The present invention relates to a digital X-ray imaging apparatus capable of shortening the length and constantly observing the condition of the subject.

[0002]

2. Description of the Related Art A conventional digital X-ray imaging apparatus of this type includes a rotary support rotatably provided around a table on which a subject is laid, and an X-ray for the subject fixed to the rotary support. , An X-ray detector for radiating the X-ray, an X-ray detector for converting the transmitted X-ray image of the object into an optical image, which is arranged to face the X-ray tube on the rotary support while sandwiching the table therebetween, and the X-ray. An image pickup apparatus for taking an optical image output from a detector, an image processing apparatus for digitizing a video signal from the image pickup apparatus, processing the digital signal, and converting the processed image data into an analog signal, and the image processing apparatus. The display device for inputting the image signal from the display device and displaying an image, the rotation control device for controlling the rotation operation of the rotation supporter, and the system control device for controlling the operation of each of the above-mentioned components. As a proposal example of such a digital X-ray imaging apparatus, for example, one described in JP-A-2-156778 (first conventional example) or one described in JP-A-3-55040 (second Conventional example).

[0003]

However, when performing an angiographic examination in the above-mentioned first conventional example and second conventional example, for example, the rotary support is rotated around the subject, and the X-ray tube apparatus and When the X-ray detector rotates in the normal direction, the X
The X-ray tube device and the X-ray detector are reversed and returned to the original reference position, and then a contrast agent is injected into the subject using a catheter. After the injection, the rotary support was activated again, and at the time of the normal rotation this time, the transmission X-ray image of the subject after the injection of the contrast agent was photographed by the X-ray tube device and the X-ray detector. Therefore, it takes time to reverse the X-ray tube device and the X-ray detector to return to the initial reference position in order to capture the blood vessel images before and after injecting the contrast agent into the subject. It took a long time to finish. From this, the restraint time for the subject becomes long and the mental burden may increase. Also, during the period in which the X-ray tube device and the X-ray detector are reversed and returned, a transmission X-ray image of the subject cannot be obtained, so an operator such as a doctor should observe the condition of the subject. However, there was a concern that the subject could not cope with a sudden change in his condition.

Further, in the first conventional example, two television monitors are provided as display devices, and two images having a predetermined phase difference obtained by photographing at the time of forward rotation are simultaneously displayed on each television monitor. Since it is displayed and an operator such as a doctor can see them stereoscopically with both eyes, it is not possible for a large number of people to simultaneously observe stereoscopic images.

Further, in the second conventional example, a so-called C-arm or U-arm is used as the rotary support, and the arm is exposed and the reproducibility of the position of the arm during rotation is improved. Since it was not so good, the rotation speed during shooting was kept low, for example, 10 degrees / second. Therefore, the time required for the entire imaging is further increased, and the contrast medium must be injected into the subject for a long time, which may cause pain to the subject. For this reason, it is necessary to take measures such as narrowing the imaging angle range for the subject, and it may not be possible to obtain sufficient diagnostic information.

Therefore, the present invention addresses such problems and shortens the time required for imaging by rotating the X-ray tube device and the X-ray detector around the subject, and It is an object of the present invention to provide a digital X-ray imaging apparatus capable of always observing the situation.

[0007]

In order to achieve the above object, a digital X-ray imaging apparatus according to the present invention is provided with a rotary support rotatably provided around a table on which a subject is laid, and a rotation support. An X-ray tube device that is fixed to a support and emits X-rays to the subject, and the table is sandwiched between the X-ray tube device and the X-ray tube device that are arranged to face the X-ray tube device and convert a transmitted X-ray image of the subject into an optical image. X-ray detector, an image pickup device for taking an optical image output from the X-ray detector, a video signal from the image pickup device is digitized, the digital signal is processed, and the processed image data is converted into an analog signal. Image processing apparatus, a display apparatus for displaying an image by inputting a video signal from the image processing apparatus, a rotation control apparatus for controlling the rotation operation of the rotary support, and a system for controlling the operation of each of the components. Control equipment In the digital X-ray imaging apparatus provided with the above, the rotation control device is configured to control the rotation support so as to be capable of normal rotation and reverse rotation between arbitrary angles, and the system control device includes the normal rotation of the rotation support. In addition, the X-ray tube device is configured to continuously emit X-rays during the reverse rotation and the forward / reverse inversion so as to enable image capturing.

Further, the system control device is configured to repeat the normal rotation and the reverse rotation of the rotary supporter an arbitrary number of times and to continuously control X-ray imaging during the repetition.

Further, the image processing apparatus is configured to perform calculation by using image data having the same phase angle, which are taken in at the time of normal rotation and reverse rotation of the rotary support.

[0010]

In the digital X-ray imaging apparatus thus constructed, the rotation control device controls the X-ray tube device and the rotation support of the X-ray detector so as to be able to rotate normally and reversely at an arbitrary angle, thereby controlling the system. The apparatus operates so that X-rays are continuously emitted from the X-ray tube apparatus during the forward rotation, the reverse rotation, and the forward / reverse rotation of the rotary support so as to control the image capture. As a result, the time required for imaging can be shortened and the condition of the subject can always be observed.

[0011]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing the overall configuration of a digital X-ray imaging apparatus according to the present invention. This digital X-ray imaging apparatus includes an X-ray tube device and an X-ray device around the subject.
The X-ray is emitted to the subject while rotating the X-ray detector, the transmitted X-ray image is detected, the X-ray is photographed, and the diagnostic site of the subject can be observed as a stereoscopic image. To
The rotary support 1, the X-ray tube device 2, the X-ray detector 3, the television camera 4, the image processing device 5, the display device 6, the rotation control device 7, and the system control device 8 are provided. Become.

The rotary support 1 is an X-ray tube device 2 described later.
Also, the X-ray detector 3 is rotatably supported and is formed in a ring shape having a rotation center O in the vicinity of a table 10 on which the subject 9 is laid, and is rotatably provided around the table 10. And is rotated by a drive mechanism (not shown). The subject 9 is placed on the upper surface of the table 10 at the position of the rotation center O.

The X-ray tube device 2 radiates X-rays to the subject 9 lying on the table 10, and is supplied with a predetermined high voltage from the high voltage device 11.
The X-ray detector 3 is a device that receives an X-ray image emitted from the X-ray tube device 2 and transmitted through the subject 9 and converts the X-ray image into an optical image. The X-ray detector 3 includes, for example, an X-ray image intensifier.
The table 10 is sandwiched between the rotary support 1 and the X-ray tube device 2 so as to be opposed thereto. The television camera 4 serves as an image pickup device that captures an optical image output from the X-ray detector 3 and converts it into an electric signal, and is connected by an optical system 12 provided on the output surface of the X-ray detector 3. It is provided to take an optical image to be imaged.

The image processing device 5 digitizes the video signal from the television camera 4, processes the digital signal, and converts the processed image data into an analog signal. A / D converter 13 for inputting the image signal of the above and converting it into a digital signal, a memory 14 for storing the image data output from this A / D converter 13, and image data read from this memory 14. D / A converter 15 for inputting the input signal and converting it into an analog video signal again, and the A / D converter 13 described above.
It is composed of a large-capacity storage device 16 that stores a large number of image data output from the storage device 14 and an arithmetic processing unit 17 that takes in the image data from the storage device 14 and the large-capacity storage device 16 and performs a required operation. There is. The display device 6 receives the video signal output from the image processing device 5 and displays it as an image, and is composed of, for example, a television monitor.

The rotation control device 7 controls the rotation operation of the rotation supporter 1 such as the rotation direction, speed and angle, and a signal from the rotary encoder 18 for detecting the actual position of the rotation supporter 1. To enter.
Further, the system control device 8 controls the operation of each of the above components. In FIG. 1, reference numeral 19
Indicates an operation device for inputting various operation commands to the system control device 8, and reference numeral 20 indicates the operation device 19
Reference numeral 21 denotes an operator such as a doctor who operates the
2 shows a contrast agent injector for injecting a contrast agent into the human body.

In the present invention, the rotation control device 7 sets the rotation support device 1 at an arbitrary angle, for example, 0 degree.
It is configured such that it can be controlled to rotate forward and backward between 180 degrees. That is, the converter 22 for inputting and converting the actual position signal of the rotary support 1 from the rotary encoder 18, and the actual position signal of the rotary support 1 input from this converter 22 and the system controller 8 are input. And a comparator 23 for comparing the target position signal with the comparator 23.
A servo amplifier 24 for inputting and amplifying an error signal output from the servo amplifier 24, and a drive circuit 25 including a servomotor that operates by the drive signal from the servo amplifier 24 to drive the rotary supporter 1 to rotate. There is. Further, the system control device 8 is configured to continuously emit X-rays from the X-ray tube device 2 during the normal rotation and the reverse rotation of the rotary support 1 and the forward and reverse rotation periods so as to perform imaging control. ing. That is, the logical operation unit 26 that inputs and calculates the actual position signal of the rotary supporter 1 from the rotary encoder 18 and the operation command from the operation unit 19, and the command from this logical operation unit 26, the high voltage device 11 And an X-ray control interface 27 for sending to. The operation device 19 includes a shooting mode selection switch 28, a shooting start switch 29, and a shooting stop switch 30 in addition to various operation switches and the like.

Next, the digital X thus constructed
The operation of the line imaging apparatus will be described with reference to FIG.
In the following operation example, the point P on the rotary support 1 in FIG. 1 is set at a position of 0 degrees, and the point Q is set at a position of 180 degrees.
The X-ray detector 3 for the subject 9 is between the points P and Q.
The case of shooting while moving within a range of 180 degrees will be described. In FIG. 1, point P'is a standby position before operation, and point Q'is a reverse position from normal rotation to reverse rotation.

First, in FIG. 1, when the operator 20 operates a preparation switch (not shown) of the operation unit 19 to perform a preparation operation, the logical operation unit 26 of the system control unit 8 waits on the rotation support 1. The position signal at the position P ′ is sent to the comparator 23 in the rotation control device 7. In this comparator 23,
The actual position signal of the rotary support 1 detected by the rotary encoder 18 is input via the converter 22, and the comparator 23 compares these two input signals and sends the error signals of both to the servo amplifier 24. Then, the servo amplifier 24
The error signal is amplified and sent to the drive circuit 25 as a drive signal. As a result, the servomotor in the drive circuit 25 is driven to rotate the rotary support 1, and the X-ray detector 3 is moved so as to be located at the point P'of the standby position.

Next, when the operator 20 operates the photographing mode selection switch 28 of the operating device 19 to set, for example, the continuous reciprocating photographing mode, the logical calculator 26 above the rotary support 1 in a predetermined acceleration pattern. The position information (see FIG. 2A) in the A direction (forward rotation direction) from the P ′ point to the Q ′ point is updated and output to the comparator 23. As a result, the rotary supporter 1 starts to rotate in the direction A in FIG. 1 through the same operation as when moving to the standby position P ′ point, and FIG.
In (b), the velocity curve rises from the point P '.
Immediately before reaching point P in FIG. 1, the rotational speed is increased to a predetermined speed, for example, 180 degrees / 2 seconds. At this time,
As shown in FIG. 2 (b), the speed settles down to a predetermined speed immediately before the point P is reached. After that, as shown in FIG. 2A, the position information is updated at a predetermined cycle and output to the comparator 23 shown in FIG. 1. However, the target position signal of the rotary support 1 is updated at a constant cycle. Therefore, the servo amplifier 24 and the drive circuit 2
By the action of 5, the rotary support 1 continues to rotate in the A direction at a constant speed. At this time, the X-ray tube device 2 also moves at a constant speed A
Rotate in the direction.

Thus, the fact that the X-ray detector 3 has reached the point P is detected by the logical operation unit 26 monitoring the actual position signal of the rotary support 1 from the rotary encoder 18 shown in FIG. Then, the logical operation unit 26 drives the high voltage device 11 through the X-ray control interface 27, and the high voltage device 11 generates a pulsed high voltage of, for example, 4 msec. Then, this pulsed high voltage is applied to the X-ray tube device 2, and thereby the X-ray tube device 2 emits an X-ray pulse as shown in FIG.

The X-ray pulse radiated as described above passes through the subject 9 lying on the table 10, and the transmitted X-ray image is incident on the X-ray detector 3. Then, the incident transmission X-ray image is converted into an optical image by the X-ray detector 3, and is imaged on the incident surface of the television camera 4 via the optical system 12, and is captured by the television camera 4.

Next, the video signal output from the television camera 4 is input to the image processing device 5. Then, this video signal is converted into a digital signal by the A / D converter 13 to be, for example, image data in frame units of 512 × 512 matrix, and stored in the next storage device 14 as shown in FIG. Sequentially stored. At this time, the rotary encoder 1
The rotation angle of the rotary support 1 is detected at 8. For example, the X-ray emission and the acquisition of the image data are continuously performed by the control of the system controller 8 at every rotation angle of 1 degree. Then, the detected angle information is also stored in the storage unit 14 via the arithmetic processing unit 17 as image data of A ₁ , A ₂ , ..., An as shown in FIG. It

Next, the stored image data A ₁ to
An is sequentially read from the storage device 14 and input to the D / A converter 15 to be converted into an analog video signal. Thereafter, this video signal is input to the display device 6 and continuously displayed on the screen. Since the images of A _{1 to} An displayed continuously have different X-ray emission directions from the rotating X-ray tube device 2 for each frame image, the afterimage effect of the human eye viewing those images. Is recognized as a stereoscopic image.

In this way, as shown in FIGS. 2 (d) and 2 (e), continuous photographing is performed, and when the Q point shown in FIGS. 1 and 2 (b) is reached, the system controller 8 When the logical operation unit 26 therein recognizes by monitoring the actual position signal from the rotary encoder 18, the logical operation unit 26
The position information is updated and sent to the comparator 23 in the rotation control device 7 until the position information corresponding to the reversal position Q ′ is obtained in a predetermined deceleration pattern as shown in FIG. As a result, the servo amplifier 24 and the drive circuit 25 are
As shown in (b), the deceleration of the rotary support 1 is started,
Stop once at point Q '.

After that, the logical operation unit 26 makes the B from the point Q'to the point P'on the rotary support 1 with a predetermined acceleration pattern.
Direction information (reverse direction) is updated, and the comparator 23
Output to. As a result, the rotary supporter 1 reverses at the Q'point and starts rotating in the B direction in the same manner as in the A direction, and the speed curve rises from the Q'point in FIG. 2B. Immediately before reaching the point Q in FIG. 1, the rotational speed is increased to the same rotational speed as that in the rotation in the A direction. At this time, as shown in FIG. 2 (b), the vehicle reaches a predetermined speed immediately before the point Q is reached. 2 (d) and 2 (e) during the period of deceleration → stop → reverse → acceleration from point Q to point Q ′ during forward rotation and point Q ′ to point Q during reverse rotation.
As shown in, the image pickup is continued at the same speed as the image pickup from the point P to the point Q, and the capture of the image data is continued.

At this time, as shown in FIG. 2 (c), the contrast agent injector 21 shown in FIG. 1 is operated at an appropriate timing between the Q point during the forward rotation and the Q point during the reverse rotation. Then, the injection of the contrast medium into the body (artery) of the subject 9 is started. Then, the injection of the contrast medium ends at an appropriate timing before point P at the time of reverse rotation.

As described above, the fact that the X-ray detector 3 is inverted and reaches point Q is detected by the logical operation unit 26 monitoring the actual position signal of the rotary support 1 from the rotary encoder 18. Then, the logical operation unit 26 resynchronizes the X-ray pulse emission and the image acquisition at this Q point, updates the position information at a constant cycle as in the case of the A direction, and outputs it to the comparator 23. To do. As a result, the rotation support device 1 is operated by the functions of the servo amplifier 24 and the drive circuit 25.
Continues to rotate in the B direction at a constant speed, images are taken in the same cycle as in the case of the A direction, and as shown in FIG. 2 (e), the image data is represented by, for example, Bn, ..., B ₂ , B ₁ . It is taken in and memorized. As a result, images after injection of the contrast agent can be collected.

When the logical operation unit 26 recognizes that the point P shown in FIGS. 1 and 2 (b) has been reached by continuously taking images by rotating in the B direction in this way, the rotation in the A direction causes In the same way as when the point Q is reached, deceleration is started, stopped once at point P ', then reversed again in the direction A, and the speed is further increased. 2 (d) and 2 (e) during the period of deceleration → stop → reverse → acceleration from point P to point P ′ during reverse rotation and from point P ′ to point P during forward rotation. As shown in the above, shooting is continued at the same speed in the same manner as described above, and capture of image data is continued.

Next, when the X-ray detector 3 is rotated to reach point P again due to the reversal in the direction A, the logical operation unit 26
Recognizes this, re-synchronizes the emission of the X-ray pulse and the image acquisition at the point P, and continues the photographing in the same manner as the previous rotation in the A direction. Through the series of operations described above, the rotation support 1 is rotated in the normal direction A and B until the contrast medium injected into the artery of the subject 9 reaches the vein and flows out of the body.
Reversal in the direction is repeated an arbitrary number of times, during which X-ray photography is continuously performed.

Next, in order to perform subtraction between the two images photographed as described above and perform subtraction processing,
As shown in (b) and (c), the images A _{1 to} An (see FIG. 2 (e)) from point P to point Q, which was first photographed in the state where the contrast agent is not injected into the subject, are displayed. Images Bn to B ₁ (see FIG. 2 (e)) from points Q to P taken at the time of reversal after injection of a contrast agent are used as live images, and images between corresponding corresponding phase angles are used as mask images. This can be realized by subtraction by the arithmetic processing unit 17 in the image processing apparatus 5 shown in FIG. As a result, as shown in FIG. 2 (f), B ₁ -A ₁ ,
B ₂ -A _2, ..., subtraction images are sequentially obtained as Bn-An. Alternatively, the mask images may be subtracted from each other or the live images may be subtracted from each other.

In the above description, the photographing mode is the continuous reciprocating photographing mode. However, when it is not necessary to photograph the vein phase, the photographing mode selection switch 2 of the operation device 19 is used.
If the user operates 8 to enter, for example, the one-way imaging mode, the number of times the X-ray detector 3 is inverted can be reduced to one and the imaging can be completed in a short time. Further, the above series of operations has been described on the premise of subtraction between the mask image and the live image. However, when the subtraction is not performed, it is appropriate to take an image from the P point to the Q point for the first time. The contrast agent may be injected into the subject at a timing.

In the embodiment shown in FIG. 1, the rotary encoder 1 is used as a means for detecting the rotation angle of the rotary support 1.
However, the present invention is not limited to this, and the positions such as P'point, P point, Q point, Q'point of the rotary support 1 can be detected by a micro switch or the like. Good.
In this case, it can be realized by adjusting the X-ray emission from the X-ray tube device 2 and the timing of capturing an image in accordance with the synchronizing signal of the television camera 4 and precisely controlling the rotation speed of the rotary support 1. In the above description, X
Although the imaging angle range due to the rotation of the X-ray tube device 2 and the X-ray detector 3 is set to a range of 0 degrees to 180 degrees, the range is not limited to this and is, for example, 90 degrees.
It may be in the range of degrees or 360 degrees. In this case, the logical operation unit 26 of the system controller 8 may change the target position signal given to the comparator 23 of the rotation controller 7.

[0033]

Since the present invention is constructed as described above,
The rotation control device controls the X-ray tube device and the rotation support of the X-ray detector so as to be able to rotate normally and reversely at an arbitrary angle, and the system control device controls the rotation support and the reverse rotation of the rotation support and the normal and reverse rotation. X-rays can be continuously emitted from the X-ray tube device throughout the period, and control can be performed so that imaging can be performed. Therefore, in order to capture blood vessel images before and after injecting a contrast agent into a subject while rotating the X-ray tube device and the X-ray detector, the X-ray tube device and the X-ray detector are reversed and the original The time required to return to the reference position is unnecessary, and the time required to complete the entire shooting can be shortened. From this, the restraint time for the subject is shortened, and the mental burden can be reduced. In addition, since a transmitted X-ray image of the subject can be obtained during the period in which the X-ray tube device and the X-ray detector are reversed and during forward / reverse inversion, an operator such as a doctor is inspecting the subject. It is possible to always observe the entire situation of, and it is possible to cope with a sudden change in the condition of the subject. From these things, digital X
The clinical value of the radiographic apparatus can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital X-ray imaging apparatus according to the present invention,

FIG. 2 is a timing diagram for explaining the operation of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotation support, 2 ... X-ray tube apparatus, 3 ... X-ray detector, 4 ... Television camera, 5 ... Image processing apparatus, 6 ...
Display device, 7 ... Rotation control device, 8 ... System control device, 9 ... Subject, 10 ... Table, 11 ... High voltage device, 18 ... Rotary encoder, 19 ... Manipulator,
20 ... Operator, 21 ... Contrast injector.

Claims (3)

[Claims] 1. A rotary supporter rotatably provided around a table on which a subject is laid, an X-ray tube device fixed to the rotary support and radiating X-rays to the subject, and the table. An X-ray detector arranged between the X-ray tube device and the rotary support, which is sandwiched therebetween, and which converts a transmitted X-ray image of the subject into an optical image.
An image pickup apparatus for taking an optical image output from the X-ray detector, an image processing apparatus for digitizing a video signal from the image pickup apparatus, processing the digital signal, and converting the processed image data into an analog signal. A digital device including a display device for inputting a video signal from an image processing device to display an image, a rotation control device for controlling the rotation operation of the rotation supporter, and a system control device for controlling the operation of each component. In the X-ray imaging apparatus, the rotation control device is configured to control the rotation support so as to be capable of normal rotation and reverse rotation between arbitrary angles, and the system control device is configured to rotate the rotation support forward and reverse and forward and reverse. A digital X-ray imaging apparatus characterized in that X-rays are continuously radiated from an X-ray tube device during a reversal period to be controlled so that imaging is possible. 2. The system control device is configured to perform normal rotation and reverse rotation of a rotary supporter an arbitrary number of times and to continuously control X-ray imaging during the repetition. The digital X-ray imaging apparatus according to claim 1. 3. The image processing apparatus according to claim 1, wherein the image processing apparatus is configured to perform calculation by using image data having the same phase angle, which are taken in at the time of forward rotation and reverse rotation of the rotary support. Digital X-ray equipment.