JPH026469B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an X-ray diagnostic apparatus, and particularly to an X-ray diagnostic apparatus using digital radiography.

[Technical background of the invention]

In recent years, in the field of X-ray diagnosis, especially angiography, techniques called ``digital radiography'' or ``digital fluoroscopy'' that apply time subtraction techniques and digital processing techniques have been used. I've become like that. This converts the X-ray television video signal into an A/D (analog/
A mask X-ray image (MASK・IMAGE) is obtained by integrating several frames of X-ray fluoroscopic images without applying a contrast agent to the first image using two digital memories. Furthermore, the X-ray fluoroscopic images after contrast medium injection that are sent thereafter are respectively stored in a second memory, and a subtraction operation is performed between the images stored in the first and second memories. A subtraction image signal, which is a difference image obtained by this, is created, and the subtraction image signal is converted to a D/A.
(digital/analog) conversion to create an analog video signal, which can be displayed on a CRT (cathode ray tube), or made into a film image using a multi-format camera that takes multiple frames on a single film. By using this method, it is possible to use not only the conventional contrast agent injection method using an arterial catheter, but also the intravenous injection method that does not use an arterial catheter, allowing for safer, faster and more accurate cardiovascular system diagnosis. Oritomi is attracting attention because it has the advantage of being possible.

Basically, it can be called digital subtraction angiography, and Mask Mode images are taken of areas that are relatively static.
Radiography (Mask Mode Radiography)
There is also a mode that can be called mask mode fluoroscopy, and a mode that can be called mask mode fluoroscopy, whose main purpose is to diagnose the dynamics of moving parts.

Here, we will focus on mask mode fluoroscopy, which focuses on diagnosing moving parts.

Primarily, digital subtraction using intravenous injection is attracting attention as a future alternative to cineangiography in contrast-enhanced diagnostics of the heart, especially since it poses less risk to patients. Mask mode fluoroscopy is
Also called Continuous Imaging, as shown in Figure 1, a contrast agent is injected into the brachial vein of the subject P using an injector In while performing X-ray fluoroscopy. Frame integral image) M is obtained, then an X-ray fluoroscopic image after contrast agent injection is obtained, and the subtraction Sb between the mask image M and the X-ray fluoroscopic image after contrast agent injection is determined by the synchronization signal from the television camera. It processes continuously at frames per second, and the results can be sequentially output and recorded to external memory (videotape, video disk, IC memory, etc.). At the same time, it is also possible to store the mask image in a memory on a separate channel and output it to the monitor at the same time as the fluoroscopy is completed, but this idea is closer to mask mode radiography than dynamic observation, so I will not touch on it here. do not have.

Digital radiography is basically a contrast examination as described above, so if you want several contrast subtraction images, you will have to re-inject the contrast medium and take the images again. Because the blood vessels of the human body have overlapping anatomy, the contrast agent can be injected at several different locations by changing the patient's position or rotating the X-ray-II (image intensifier) system. Take a photo.

However, in order to reduce the mental and physical burden on patients, reduce risks, and reduce the amount of X-ray exposure, there is a strong desire to inject the contrast medium at once and obtain as much diagnostic information as possible. This must be met.

To this end, stereoscopic vision in digital radiography is desired, which allows X-ray images to be obtained as digital information and image processed to enable image enhancement and partial extraction.

On the other hand, considering real-time stereoscopic viewing as an X-ray television system, the current situation is as follows.

That is, by using an X-ray source that alternately generates two X-rays with different radiation positions, one for the right image and one for the left image, and by directing and irradiating these two X-rays toward the subject, the The X-ray image is captured by an II placed behind the subject, and the output image optically converted by this II is
Images in both directions are obtained alternately by capturing images with two image sensors, but since the image sensor (for example, an image sensor tube such as a vidicon) has an afterimage, the afterimage in one direction disappears before the image in the other direction is obtained. If the image is not inputted, images from both directions will be mixed and the three-dimensional effect will be lost. In the case of a vidicon, it usually takes about 50ms or more for the afterimage to disappear. That is 50m
X-rays in the other direction cannot be irradiated until after s.
If the shape of the object is changing at a high speed, the shape of the object will change significantly during that time.

Originally, stereoscopic vision is most accurate when the left and right images of the object at the same time are observed separately with the left and right eyes, so X-rays in both directions must be irradiated as close in time as possible. However, in the conventional method using one image sensor, this time becomes long due to afterimages, and good stereoscopic vision cannot be obtained.

[Object of the Invention] The present invention has been made in view of the above circumstances, and has achieved the X of digital radiography that has been desired in the past.
This system realizes good stereoscopic vision in mask mode fluoroscopy, which can be called the real-time subtraction mode of line television.
When using multiple image sensors, the disadvantage of the conventional method described above, which has a large time lag between left and right X-ray irradiation, can be solved, and the X-ray irradiation interval can be shortened to accurately capture a moving subject in three dimensions. The objective is to enable observation, thereby reducing the number of contrast medium injections as much as possible, and improving diagnostic accuracy through stereoscopic vision.

[Summary of the invention]

That is, in order to achieve the above object, the present invention obtains an X-ray fluoroscopic image of the subject before injection of a contrast medium, and
In an X-ray diagnostic apparatus that stores a fluoroscopic image as a mask image, forms a difference image with respect to the mask image for the fluoroscopic image of the subject after contrast medium injection, and uses this difference image for diagnosis, An X-ray source that emits two types of X-rays for images, an image intensifier that converts the X-ray image produced by the X-rays emitted by this X-ray source into an optical image, and one for left images and one for right images. An optical system device comprising independent television cameras, and an optical element on each distribution optical path that distributes the optical image to each of these television cameras and controls the input of the distributed optical image to each television camera. The optical system device controls the X-ray source based on a predetermined synchronization signal to alternately obtain X-rays for the right image and left image, and distributes optical images corresponding to the respective X-rays. A control means for controlling the opening and closing of the optical element and contrast medium injection, and a control means for controlling the opening and closing of the optical element and for controlling contrast medium injection, and a control means for receiving images taken by each television camera obtained within a predetermined period after the start of contrast medium injection, and masking each of these images. storage means for storing the image as an image; means for forming a difference image for each corresponding mask image stored in the storage means for the image received after the predetermined period; and signal processing for each of the mask images and the difference image. , consists of a means for combining image information corresponding to the left and right images respectively to be obtained within one screen, and a display means for respectively displaying the combined mask image and the difference image, X-rays are emitted alternately from an X-ray source, and the optical element of the optical system device is controlled to open and close, and the optical image of the right-hand X-ray is captured by the right-hand television camera. In addition, the X-ray image of the left X-ray is taken by the left TV camera, and among the images taken with these TV cameras, the image corresponding to the mask image is saved, and the image after the contrast agent has been distributed is stored. The difference between the mask image and the mask image is calculated to obtain a difference image, and the mask image and the difference image are each subjected to signal processing so that left and right image information can be obtained on one screen, and then each is displayed on a display means. ,
It can be displayed as a stereoscopic image, and by using optical elements for the left and right TV cameras, each TV camera is prevented from seeing the image of the other, and the left and right images can be displayed at high speed. Since it is possible to obtain three-dimensional information through stereoscopic viewing, it is possible to perform diagnosis with a single injection of contrast agent, and the difference between the mask image and To enable more accurate diagnosis to be made quickly since both stereoscopic images can be observed.

[Practice of the invention]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows a system block diagram of the present invention. In the present invention, a stereo X-ray tube with one target and two focal points is used, and the two focal points are alternately switched to obtain X-ray fluoroscopic images (captured images) for the right and left images, and this X-ray fluoroscopic image is The image is formed on an image intensifier (II) for X-ray-light conversion,
Converts into an optical image, guides this optical image to an optical system device via a primary lens, and distributes the light after passing through this primary lens to, for example, two television cameras at a ratio of 50:50 each using a half mirror. and send them through each secondary lens. The X-ray system is
This is obtained as an analog video signal from X-ray television, but by A/D converting it and operating digital radiography, images for subtraction can be obtained from each of the two television cameras. On the other hand, the two television cameras have a certain relationship in their synchronization systems, and finally the images are combined so that the left and right images are displayed in parallel in one image. Then, when displaying on the CRT display device, the images for the right eye and the image for the left eye are displayed together on one TV monitor, so that the left image is viewed with the left eye and the right image is viewed with the right eye. Make it possible to observe it as a three-dimensional image.

In Fig. 2, 1 is a one-target, two-focal type stereo X-ray tube, in which two cathodes Kr and Kl are opposed to a rotary anode P in the shape of a dome, which is the target for X-ray conversion. It is provided. Kr is for right image,
Kl is a cathode for emitting X-rays for the left image, and these are placed at a distance necessary to obtain left and right images for stereoscopic vision, and thermionic electrons are emitted from the cathodes Kr and Kl. As a result, left and right X-rays are emitted from the target collision point of these thermoelectrons. Note that this is a grid for controlling thermionic emission of Gr. 2 is a subject; 3 is an image intensifier (II) that receives the X-rays emitted from the X-ray tube 1 and obtained through the subject 2 on an input surface and converts them into an optical image; The optical system device includes an II lens (primary lens) 41 provided on the II output surface side, a half mirror 42 that distributes the image guided by this primary lens 41, a television camera lens (secondary lens) 43, 44, optical elements 45 and 46 are provided on the front side of the secondary lenses 43 and 44 to interrupt the optical path. The optical system device 4 has a half mirror 42 arranged at an angle of 45 degrees with respect to the optical axis of the primary lens 41, and the secondary lens 44 is positioned on the transmission optical axis of the half mirror 42. A secondary lens 43 is provided on the reflection optical axis, and these secondary lenses 4
Television camera heads 5 and 6 are arranged behind the two television camera heads 3 and 44, and the output X-ray image of II is distributed to the two television camera heads 5 and 6. The first television camera head 5 and the second television camera head 6 are in a television synchronization relationship which will be described later. Reference numerals 7 and 8 denote television camera controllers for controlling vertical and horizontal scanning of the television camera heads 5 and 6, and a synchronization relationship is also given to the television system controller 14. Reference numeral 9 denotes a controller that controls the entire system, including X-ray exposure timing, exposure control of the X-ray tube 1, control of the digital processor 13 (described later), commands for the contrast agent injection device (injector) 17, and optical system equipment. 4
There is also an optical diaphragm (auto iris) for the television camera lens set inside the lens, and a glazing element 45.
46 ON/OFF controls, TV camera head 5,
Controls beam blanking, etc. of the image pickup tube No. 6. 10 is an X-ray controller that generates X-ray exposure switching control outputs for the right and left sides of the X-ray tube 1 in response to commands from the controller 9; An X-ray high-voltage generator 12 that generates a high voltage serving as the set tube voltage and tube current and applies it to the X-ray tube 1 operates in response to the X-ray exposure switching control output output from the X-ray controller 10, This is an X-ray tube switching controller that controls the bias of the corresponding grids Gl and Gr of the X-ray tube 1 to turn them on and off. 13 is a digital processor that digitizes and stores the output video signals of the television camera heads 5 and 6 given via the television camera controllers 7 and 8, obtains a subtraction image based on the mask image, and processes the image. It has the function of converting data into analog and outputting it. Reference numeral 14 denotes a television system controller, which mixes and outputs the left and right video signals into a parallel left and right image for stereoscopic viewing, and includes a gate for extracting necessary parts of each of the left and right video signals. 143, 144, a synchronous signal generator 141, a logic control unit 147 that controls the gates 143, 144 in synchronization with the output of the synchronous signal generator 141, a mixer 145 that mixes the outputs of the gates 143, 144; The stereoscopic image for the mask image and the subtraction image can be output separately. 1
5 and 16 are television monitors, 15 is used to display a stereoscopic image of a mask image output from the television system controller 14, and 16 is used to display a stereoscopic image of a subtraction image.

The stereo X-ray tube 1 used in this device has a rotating anode P in the shape of a truncated cone, and two cathodes Kr and Kl are arranged opposite to the inclined surface of the rotating anode P, for example, at a distance between human eyes. , Grids Gr, Gl are arranged between these cathodes Kr, Kl and the rotating anode P, respectively, for X-ray exposure control.
By alternately switching the bias of Gl and alternately releasing the block, thermionic electrons alternately jump out from the left and right cathodes Kl and Kr, and hit the opposing slopes of the rotating anode P, forming focal points fl and fr there. And its focus fl,
X-rays are emitted from fr. Therefore, X-rays can be alternately irradiated to the left and right eyes, the field of view of which differs by the distance between the left and right eyes. Switching controller 12
The X-ray exposure switching control is performed by switching the bias of the grids Gr and Gl mentioned above.

Figure 3 shows the X-ray tube switching controller 12.
The configuration is shown below. In the figure, 1 is the aforementioned X-ray tube;
* indicates the positive and negative electrode high voltage outputs of the X-ray high pressure generator 11. The X-ray tube switching controller 12 is for a stereo X-ray tube 1 of bifocal type, and cathodes are provided for the left and right sides, respectively, and therefore, respective control circuits are provided.

Since these control circuits have the same configuration for both left and right control circuits, only one circuit will be explained here, and the other one will be shown only in the drawings and its explanation will be omitted.

In addition, in the following explanation, the subscript r is added for right-hand use, and l is added for left-hand use.

In the figure, reference numeral 121 denotes a filament heating transformer, which receives the output of the X-ray high voltage generator 11, generates a corresponding heating voltage, and applies it to the corresponding cathode of the X-ray tube 1.

122 is a transformer for generating grid bias for the X-ray tube 1, which receives a commercial 100V power supply and transforms it. 123 is a rectifier circuit that full-wave rectifies the output of this transformer 122 and outputs it with negative polarity;
Reference numeral 4 denotes a tetrode tube (tetrode) for controlling exposure switching of the X-ray tube 1, which is connected between the corresponding grids and cathodes of the X-ray tube 1 so that the cathodes are connected to each other. 125 is a tetrode tube 124
This is the second grid bias power supply connected between the cathode of the bus and the second grid.
The second grid bias is appropriately set to a positive potential to bring the internal resistance of the tetrode tube 124 to an optimum value.
126 is a capacitor connected between the output terminals of the rectifier circuit 123, 127 is a capacitor connected between the rectifier circuit 123 and X
A resistor 128 connected between the corresponding grid of the tetrode tube 1 is a bias power supply for the first grid connected between the cathode of the tetrode tube 124 and the first grid, and biases the first grid negatively. It is connected like this.

129 is a photocoupler that operates in response to the X-ray exposure switching control output given by the X-ray controller 10, and 130 is a switching transistor that operates based on the output of this photocoupler 129. This transistor 130 has its emitter side connected to the cathode side of the first grid bias power supply 128 via a resistor 131, and its collector side connected to its anode side.

Next, the operation of this apparatus having the above configuration will be explained. First, the X-ray tube switching controller 12
Explain the operation.

The high voltage output generated by the X-ray high voltage generator 11 is applied between the cathode and the anode of the X-ray tube 1, and is also applied to the cathode as a filament heating voltage via the filament heating transformer 121.

On the other hand, the output of the transformer 122 is
The negative side is applied to the grid of the X-ray tube 1 through the resistor 127, and the positive side is applied to the cathode. This causes the corresponding grid-to-cathode bias of the X-ray tube 1 to be reverse biased by the output voltage of the rectifier circuit 123, placing the X-ray tube 1 in a cut-off state.

The voltage between the output terminals of the rectifier circuit 123 is applied to the tetrode tube 124 as a tube voltage, but the voltage between the first grid and the cathode is reverse biased by the bias power supply 128 for the first grid, and the tetrode tube 124 is cut off under normal conditions. in a state.

Next, from the X-ray controller 10, the photocoupler 1
When the X-ray exposure switching control output is given to 29, the output of the photocoupler 129 causes the transistor 1 to
30 is turned on, the transistor 130 and the resistor 13 of the output of the bias power supply 128 for the first grid are turned on.
Since the voltage drops through the closed loop formed by 1, the reverse bias applied to the first grid is removed and the tetrode tube 124 is turned on. Therefore, the output of the rectifier circuit 123 is connected to the resistor 127.
and flows through the closed loop formed by the tetrode tube 124, and the voltage is dropped by the resistor 127, so that
The reverse bias applied to the grid of the ray tube 1 is removed, and thermionic electrons are emitted from the corresponding cathode of the grid and impinge on the cathode.

As a result, X-rays are emitted from the X-ray tube 1.

When the X-ray exposure switching control output disappears, the photocoupler 129 is turned off, so the transistor 130 is also turned off, and the first tetrode tube 124 is turned off.
Since the grid bias is also applied as a reverse bias again, this tetrode tube 124 is in a cut-off state. Therefore, since the grid of the X-ray tube 1 is also reverse biased again, the X-ray tube 1 is cut off and X-ray exposure is stopped.

In this way, the X-ray exposure switching control output controls the right and left photo couplers 129r and 129.
X-ray exposure for the right and left can be controlled by turning on and off.

FIG. 4 shows details of the digital processor 13. The digital processor 13 is an image processing unit that can be called the heart of digital radiography, and the apparatus of the present invention has two systems for stereo, one for the right side and one for the left side, but each has the same configuration. Only one system will be explained, and the explanation of the other will be omitted. In order to distinguish between the left and right systems, the subscript r is added to the right side and l is added to the left side, but these will be omitted in the explanation.

The digital processor 13 basically performs high-speed analog-to-digital conversion (A/D conversion) of the video signal from the X-ray television camera, performs image processing calculations in real time using frame memory for two series, and performs image enhancement processing. This is an X-ray television image digital processing device that performs digital-to-analog conversion (D/A conversion) and outputs the image to an X-ray television monitor.

The configuration will be explained below. In the figure, 131 is a log amplifier that logarithmically amplifies the video signal, 132 is an A/D converter that digitally converts the output of the log amplifier 131, 133 is an image processing calculation unit,
4, 135 is a frame memory, and the image processing calculation unit 133 stores the A/D converter output in the frame memory 134, and basically stores the output of the A/D converter in the frame memory 134 according to a preset algorithm.
It performs operations such as obtaining subtraction image data between two images, the image stored in the image and the input image. The frame memory 134 stores mask image data under the control of the image processing calculation unit 133, and the frame memory 135 stores image data obtained thereafter. Incidentally, the mask image and the instantaneous subtraction image between the images obtained thereafter can be directly D/A converted and output. In addition, frame memory 1 is used to integrate instantaneous subtraction images.
35 is used. 136 is a switch 1 for selecting whether to display a mask image or a subtraction image on the TV monitor I (15 in FIG. 2);
37 is a D/A converter that converts the frame memory 134 or the output of the image processing calculation unit 133 provided through the switch 136 into analog; 138 is used for post-processing the output of the image processing calculation unit 133, that is, subtraction storage. Enhance the image of the image
This is a post-processing device that has a post-processing function. 139 is a mixer that creates an image processing composite image using a subtraction image and an image enhanced image; 140 is a D/A converter that converts the image data output from this mixer 139 into analog; The output is provided to a television monitor.

Next, the mask mode fluoroscopy operation (X-ray exposure, mask image storage, subtraction image output) in digital radiography with the above configuration and the operation for stereoscopic viewing (right-side X-ray exposure , left side X-ray exposure, right side video signal output, left side video signal output), etc. will be explained with reference to the time chart shown in FIG.

When an operation start command is given to the system controller 9, the system controller 9 gives a command to the injector 17 to start contrast medium injection into the brachial vein of the subject 2, as shown in FIG. 5l, and the contrast medium injection is started. In addition, the television system controller 14
The vertical synchronization signal (fifth
Figure a) is output and given to the television camera controllers 7 and 8 and the system controller 9. Then, the system controller 9 first instructs the X-ray controller 10 to emit X-rays from the right focal point fr of the X-ray tube 1 using the first vertical synchronization signal in order to obtain a mask image. Then, the X-ray controller 10 applies a reverse bias to the right side grid Gr to the X-ray switching controller 12 for a predetermined time width (for example, 2 to 3 ms).
As a result, the X-ray tube 1 emits right pulse X-rays from the right X-ray focal point fr as shown in FIG. 5b. This X-ray passes through the subject 2 and enters II3, where it is converted into a visible image and output as an output image. The visible image output to the output surface passes through the primary lens 41 and then passes through the half mirror 4.
2, it is distributed to the television camera heads 5 and 6 at a distribution ratio of 50:50.

Now, of the TV cameras 5 and 6, 6 are for the right side, 5
is for the left side, the system controller 9 synchronizes with the previous vertical synchronization signal until the next vertical synchronization signal is generated, as shown in FIG. 46 close signal and a beam blanking signal generation command for the right TV camera head 6. Therefore, only the right-hand side optical element 45 is open, and since the beam ranking of the TV camera head 6 is performed by the system controller 9, the distributed visible image is transferred to the right-hand TV camera head 6. imaged and accumulated.

When the next vertical synchronization signal is generated, the system controller 9 in turn gives a command to the X-ray controller 10 to perform X-ray exposure from the left focal point fl, and thereby the X-ray controller 10 activates the X-ray switching controller 12. The reverse bias of the grid Gl for the left side is set for a predetermined time width (for example, 2 to 3 ms).
As a result, left pulsed X-rays are emitted from the X-ray tube 1 as shown in FIG. 5c.

This X-ray passes through the object 2 and enters II3,
After being converted into a visible image here, the primary lens 41,
This visible image is distributed to the television camera heads 5, 6 through the half mirror 42.

At this time, the system controller 9 synchronizes with the vertical synchronizing signal until the next vertical synchronizing signal is generated, as shown in FIG.
In order to output a command to generate a close signal for the left TV camera head 5 and a beam blanking signal for the left TV camera head 5, only the left side optical element 46 is opened, and the left TV camera head 5 is in beam blanking mode. The visual image is focused on the television camera head 5 and accumulated.

On the other hand, since the beam blanking of the TV camera head 6 for the right side is removed, the video signal of the previously accumulated image is read out as shown in Fig. 5f.
The data is input to the digital processor 13 via the television camera controller 8. Here, reading is performed after beam blanking using pulsed X
This is because the visible image becomes pulse-like due to the line, so it is necessary to allow time for the image pickup element of the television camera head to rise. In the digital processor 13, this video signal is input to the right side system, logarithmically amplified by the log amplifier 131, and then A/
The signal is converted into a digital signal by the D converter 132 and further inputted to the image processing calculation section 133.

Since the mask image is now being taken in, the image processing calculation unit 133 issues a storage command as shown in FIG. 5h according to the set algorithm, and stores the digital signal in the frame memory 134.

When the next vertical synchronization signal is generated, the system controller 9 controls the X-ray exposure to be stopped.
Therefore, during this period, as shown in Fig. 5d and e, beam blanking is not applied to both the left and right sides.
Right TV camera head 6,5 to Figure 5f,
As shown in g, video signals are outputted and inputted to respective corresponding systems of the digital processor 13 via television camera controllers 7 and 8. Then, the video signal converted into a digital signal in the same manner as described above is stored in the frame memory 134.

When the next vertical synchronization signal is generated, X-ray exposure for the right side is performed again, and after the X-ray exposure for the left side is performed at the next vertical synchronization signal, a pause period is provided for a while.

In this way, pulsed X-rays are emitted twice on the left and twice on the right, and the respective video signals are added and stored in the frame memory 134 of the corresponding system, as shown in FIG.
Frame memories 134 as shown in j and k, respectively.
An integral image for the mask is obtained. The contents of the two frame memories 134 are provided to a D/A converter 137 via a switch 136, where they are converted into analog data and then sent to the television system controller 14.
is input.

Gate 14 of television system controller 14 is controlled by logic control unit 147.
3, 144 to the mixer 145, where the image L of the X-rays from the left X-ray focal point fl and the image R of the X-rays from the right X-ray focal point fl are arranged on the left and right sides of one screen. In other words, after mixing to create a stereoscopic screen, the synchronous signal mixer 1
46, where a synchronizing signal is added and applied to one television monitor 15, where a stereoscopic image is displayed using a mask image.

The contrast medium is injected into the brachial vein prior to X-ray exposure, and if the area to be examined is the heart, it takes time for the contrast medium to reach the heart, so the above mask image is a contrast medium. Obtained as an image before drug injection.

On the other hand, as shown in FIG. 5l, after a predetermined delay time has elapsed after the mask image is captured, the system controller 9 controls to start pulsed X-ray exposure again in synchronization with the vertical synchronization signal. At this stage, the contrast agent has reached the heart.

This time, since the object is to obtain a subtraction image, the system controller 9 irradiates the right side X-ray every four cycles of the vertical synchronization signal (Fig. 5a), and one cycle later, the left side X-ray is emitted. control to emit X-rays.

Then, during one cycle period of the vertical synchronization signal during right side X-ray exposure, the right optical element 4 of the optical system device 4
6 and performs beam blanking for the right TV camera head 5. Also, during one cycle of the vertical synchronization signal when emitting X-rays for the left side, the optical system device 4 is opened.
The left-hand side optical element 45 is opened, and beam blanking of the left-hand television camera head 6 is applied.

As a result, the image obtained by X-ray exposure for the right side is accumulated in the TV camera head 6 for the right side, and the image obtained by the X-ray exposure for the left side is accumulated in the TV camera head 5 for the left side. After the next vertical synchronization signal is generated after each X-ray exposure, the accumulated images are sequentially read out as video signals and input to the digital processor 13 via the television camera controllers 7 and 8.

As a result, the digital processor 13 performs subtraction with the mask image in the frame memory 134 using the image processing calculation unit 133 for the first field of the video signal read out of each video signal, and generates the data of the subtraction image. It is input to the frame memory 135 as .

The subtraction image data in the frame memory 135 is stored in the next X as shown in FIG.
Until new subtraction images are obtained after radiation exposure, they are repeatedly read out and input to the television system controller 14, mixed so that the left and right images are juxtaposed on one screen, and displayed on the television monitor. 16 and displayed as a subtraction image for stereoscopic viewing.

Incidentally, the optical elements 45 and 46 are provided on the front optical path of the television camera heads 5 and 6, respectively, and are opened and closed in accordance with the right and left X-ray exposure, so that the image of the left X-ray is The right X-ray image will not be mixed into the right X-ray image, and the left X-ray image will not be mixed into the right X-ray image. Figure 6 shows a time chart of the operation of the television system. a
indicates an image captured by the image sensor in the right television camera head 6, c indicates an image captured by the image sensor in the left television camera head 5, P1 is the entire screen scanned by the image pickup tube, P2 indicates the output image of II3, and P3 indicates the range of the image to be finally displayed.

The output video signals from the television camera heads 5 and 6 are as shown in b and d, respectively, and the digital processor 13 outputs the right and left P3 images from the frame memory 134 or 135 under the control of the image processing calculation unit 133. The stored data is read out with a timing shift such that portions are adjacent to each other. After D/A conversion, the right and left video signal data read out in this manner are sent to the gates 143 and 144 of the television system controller 14, respectively.
Gates are applied so that only three parts are extracted, such as e and g, and are extracted as signals such as f and h. These signals are mixed by a mixer 145 to produce a signal like i. Then, a new synchronization signal such as j is added by the synchronization signal mixer 146 to produce a video signal such as k, and when it is applied to a television monitor and displayed, the left and right X-ray focal points are displayed on the same screen as shown in l.
A stereoscopic image in which images L and R obtained by fl and fr are lined up is obtained.

As described above, the present invention makes the television camera heads for left and right images independent, prevents left and right images from remaining in the image sensor even when the left and right X-rays are switched at high speed, and Since the X-ray irradiation is performed with a shift of one vertical synchronization signal, that is, at an interval of one field, there is almost no time difference between capturing the left and right images, and therefore, changes in the left and right images due to the movement of the subject can be suppressed (for example, compared to the conventional technology) In this case, the afterimage disappearing time is 1/3 compared to the case of 3 fields).3D observation of a moving object can be performed more accurately and easily. Furthermore, considering the interval between the next left and right X-ray illuminations, the shorter the interval, the more X-rays can be irradiated per second, which is desirable for observing a moving subject. In the conventional method using one image sensor (equivalent), it takes (3 + 1) x 2 = 8 fields to irradiate left and right X-rays once, where the afterimage disappearance time is 3 fields and the signal rise time is 1 field. The number of irradiations per second is 60/8 = 7.5 times, but according to the present invention, even if the afterimage disappearance time and rise time are the same, the number of irradiations per second is 60/4 = 15.
This means that twice the number of frames can be obtained, allowing smoother three-dimensional observation of a moving subject.

Furthermore, according to the present invention, images are obtained for stereoscopic viewing, so even when multiple examination objects overlap in front and behind, the positional relationship between them is not determined as a two-dimensional fluoroscopic image, such as a blood vessel image. Because it is clearly visible, diagnosis can be made quickly and accurately.In addition, the information necessary for diagnosis is prepared with a single contrast medium injection, and the contrast medium injections and images can be repeated multiple times while changing directions as in the past. This eliminates the need for repeated contrast medium injections, reduces the risk to the examinee due to repeated contrast medium injections, reduces the mental and physical burden on the examinee, and has the effect of reducing radiation exposure. It will be done.

Furthermore, since the left and right images can be displayed side by side on one screen, it becomes easier to observe the stereoscopic image, and since each stereoscopic image of the mask image and the subtraction image can be displayed, more accurate diagnosis is possible.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and can be implemented with appropriate modifications within the scope of the gist thereof. It is also possible to record the output image of the system controller on an external recording device, such as a video disk, video tape recorder, hard copy device, film, etc., for later diagnosis and information storage.

〔Effect of the invention〕

As described in detail above, the present invention obtains an X-ray fluoroscopic image of a subject before injection of a contrast medium, stores this X-ray fluoroscopic image of the subject as a mask image, and stores the mask image for the fluoroscopic image of a subject after injection of a contrast medium. In an X-ray diagnostic device that forms a difference image for the image and uses this difference image for diagnosis, an
a radiation source; an image intensifier that converts an X-ray image from X-rays emitted by the X-ray source into an optical image;
Independent television cameras for left and right images,
an optical system device comprising an optical element disposed on each distribution optical path for distributing the optical image to each of these television cameras and controlling the input of the distributed optical image to each television camera, and a predetermined synchronizing signal. The X-ray source is controlled based on a reference to alternately obtain X-rays for the right image and left image, and the optical element of the optical system device is opened and closed in order to distribute optical images corresponding to each X-ray. a control means for controlling the contrast medium injection; and a storage means for receiving images taken by each television camera obtained within a predetermined period after the start of the contrast medium injection and storing each of these images as a mask image. , means for forming a difference image with respect to each corresponding mask image stored in the storage means with respect to the image received after the predetermined period, and signal processing of each of these mask images and difference images, respectively, so as to correspond to left and right images, respectively. It is composed of means for compositing the parts so that they are lined up in one screen, and display means for respectively displaying the combined mask image and the difference image, and is configured to alternately expose right and left X-rays from an X-ray source. The X-ray image of the right X-ray is captured by the right television camera by controlling the opening and closing of the optical element of the optical system device, and the optical image of the right X-ray is captured by the right TV camera. The image is captured by the left TV camera, and among the images captured by these TV cameras, the image corresponding to the mask image is saved, and the image after the contrast agent has spread is calculated by taking the difference from the mask image. The mask image and the difference image are each processed so that the left and right images are lined up on one screen, and then displayed on a display means so that they can be displayed as a stereoscopic image. Also, by using optical elements for each of the left and right TV cameras, each TV camera is prevented from receiving the image of the other,
This makes it possible to capture left and right images at high speed, so it is possible to obtain left and right images at the same time without the afterimage of the left and right images, unlike in the case of a single TV camera. In addition, since it is possible to obtain three-dimensional information through stereoscopic vision, diagnosis can be performed with a single contrast agent injection, and it is also possible to observe three-dimensional images of both the mask image and the difference image. Therefore, it is possible to provide an X-ray diagnostic apparatus having characteristics such as being able to perform more accurate diagnosis quickly.

[Brief explanation of drawings]

Fig. 1 is an operation time chart explaining the basic operation of mask mode fluoroscopy in digital radiography, Fig. 2 is a system block diagram of the device of the present invention, and Fig. 3 is an X-ray switching control section. 4 is a detailed diagram of the digital processor 13, FIG. 5 is a time chart showing the system operation of the apparatus of the present invention, and FIG. 6 is a diagram for explaining the operation of the television system in the apparatus of the present invention. It is a time chart. 1... X-ray tube, 2... Subject, 3... Image intensifier, 4... Optical system device, 5, 6
... TV camera head, 7, 8 ... TV camera controller, 9 ... System controller,
10...X-ray controller, 11...X-ray high voltage generator, 12...X-ray switching controller, 13...digital processor, 14...TV system controller, 15, 16...TV monitor, 131... Log amp, 132...
A/D converter, 133... Image processing calculation unit, 13
4,135...Frame memory, 136...Switcher, 138...Post-processing device, 137,140...
D/A converter, 139, 145...mixer, 14
1...Synchronization signal generator, 143, 144...Gate, 146...Synchronization signal mixer, 147...Logic control unit.

Claims (1)

[Scope of Claims] 1. Obtain an X-ray fluoroscopic image of the subject before injection of a contrast medium, save this X-ray fluoroscopic image of the subject as a mask image, and calculate the difference between the fluoroscopic image of the subject after injection of the contrast medium and the mask image. An X-ray diagnostic device that forms an image of An image intensifier that converts an X-ray image into an optical image, an independent television camera for left and right images, and an image intensifier that distributes the optical image to each of these television cameras, and an optical system device comprising a beam optical element installed on each distribution optical path for controlling the input to each television camera; a control means for controlling the opening and closing of the optical element of the optical system device in order to alternately obtain X-rays and distribute optical images corresponding to the respective X-rays, and for controlling contrast medium injection; storage means for receiving images taken by each television camera obtained within a predetermined period after the start and storing each image as a mask image; means for forming a difference image with respect to the mask image; means for performing signal processing on each of these mask images and the difference image, and composing them so as to obtain image information corresponding to the left and right images respectively within one screen; 1. An X-ray diagnostic apparatus comprising display means for displaying a mask image and a difference image, respectively.