JPH03222587A - Angiographic device - Google Patents

Abstract

PURPOSE:To obtain an easy to see bright fluoroscopic image even with less X-ray dose by not reading a picture of an image pickup tube but storing electric charge during X-ray exposure period and reading the stored picture after the end of X-ray exposure period. CONSTITUTION:The X-ray pickup system picking up an angiographic image and an X-ray fluoroscopic system examining an angiographic image are provided to the device. The X-ray fluoroscopic system consists of a camera control unit 8, a frame memory 12 as a picture storage means, and a cathode blanking circuit 14 as a picture readout control means. Then the picture readout control means 14 does not read the picture of an image pickup tube 7 during X-ray exposure period and a fluoroscopic image outputted from an X-ray image intensifier 6 is stored electrically for X-ray exposure period in the image pickup tube 7 and picture is readout after the end of the X-ray exposure period to display the stored picture onto a monitor 10. Thus, the displayed picture is bright and observed easily independently of the X-ray does.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of Application The present invention relates to an angiography apparatus that injects a contrast medium into a blood vessel of a subject to take a blood vessel image, and particularly relates to a blood vessel image capturing apparatus that captures a blood vessel image by injecting a contrast medium into a blood vessel of a subject. The present invention relates to an angiography device suitable for imaging the abdominal vascular system.

B. Prior Art Angiography equipment includes an X-ray image intensifier, an imaging tube, and a monitor to confirm in real time whether the contrast agent injected into the subject's blood vessels has reached the area of interest. The constructed X-ray fluoroscopy system and X-ray images of blood vessels
An X-ray imaging system is provided for taking radiographs and recording them on film.

As an X-ray imaging system for imaging the vascular system of the head and abdomen of a subject, a continuous X-ray imaging device (film changer) that continuously supplies X-ray film to an imaging position is used.

This is because in areas such as the head, where the vascular system is complex and arranged three-dimensionally, the overall image is taken, and then the complex part is enlarged and imaged, and in other areas, such as the abdomen, where the vascular system is complex and arranged three-dimensionally. This is because an X-ray film with a large imaging area is used to image a large area of interest.

By making full use of such an X-ray fluoroscopy system and an X-ray imaging system, a blood vessel image is captured while checking the flow of the contrast medium in real time.

C2 Problems to be Solved by the Invention Generally, when performing X-ray close-up imaging, the X-ray conditions (X-ray time, X-ray imaging time, etc.) are taken in accordance with the composition and thickness of the area of interest, and the imaging method δ. .

For example, when taking a blood vessel image by moving the X-ray imaging system and the subject relatively from the abdomen to the legs of the subject, the thickness of the area of interest becomes gradually thinner, so the If irradiation is performed with a small amount of X-rays, the amount of X-rays transmitted through the region of interest will increase, and the density of the X-ray photograph will become thinner. Therefore, the density of the X-ray photograph is maintained at an appropriate level by reducing the X-ray dose and lengthening the imaging time accordingly.

Furthermore, when photographing the head, the distance between the X-ray tube and the region of interest is shortened in order to perform magnified photographing as described above.

If only the distance is shortened, the X-ray intensity to the region of interest will increase and the amount of transmitted X-rays will increase accordingly, so the amount of X-rays is also reduced. Therefore, as mentioned above, in order to make the density of the X-ray photograph appropriate, the imaging time is increased.

In this way, when photographing the vascular system of the head and abdomen, the xf! Blood vessel images may be taken while changing conditions.

However, an image pickup tube that performs fluoroscopy of blood vessel images in real time during X-ray imaging outputs fluoroscopic images at 30 frames per second to a monitor. That is, the optical image from the X-ray image intensifier is read out at constant time intervals regardless of the length of the X-ray In shadow time. Therefore, when increasing the maximum shadow time and decreasing the X-ray dose as described above, a dark image will be displayed on the monitor, making it difficult to see the image and confirming the flow of the contrast medium. There is a problem with that.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fluoroscopic image that is bright and easy to see even when the imaging conditions are changed during angiography. There is.

08 Means for Solving the Problems The present invention has the following configuration to achieve the above object.

That is, the present invention includes an angiography system that continuously sends an X-ray film to an imaging position to perform X-ray photography, and an X-ray image intensifier that receives transmitted X-rays that have passed through the X-ray film. In an angiography apparatus equipped with a blood vessel image fluoroscopic system that converts the visible light image into a visible light image, captures this visible light image with an image pickup tube, and displays it on a monitor, reading out the image from the image pickup tube is prohibited during X-ray exposure. an image readout control means for inhibiting and accumulating charges and reading out the image after the end of X-cotton exposure; and an image storage means for storing the image read out from the image pickup tube and outputting it to the monitor. It is characterized by the fact that it is equipped with

E1 effect According to this invention, the image readout control means
By not reading images from the image pickup tube during the X-ray exposure period, the fluoroscopic image output from the X-ray image intensifier is electrically stored in the image pickup tube during the X-ray exposure period. Then, after the X-ray exposure period ends, the accumulated images are displayed on the monitor by reading out the images. As a result, the displayed image becomes bright and easy to see, regardless of the amount of X-rays.

In addition, since the image storage means stores and holds the images read out from the imaging tube, the fluoroscopic images obtained by - times of exposure can continue to be displayed on the monitor, making it easy to confirm the angiographic image.

F. Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an angiography imaging apparatus.

The angiographic imaging apparatus according to this embodiment includes an X-ray imaging system that performs the best contrast of an angiographic image obtained by injecting a contrast medium into a blood vessel of a subject M, and an X-ray imaging system that performs fluoroscopy of the angiographic image. It is equipped with a fluoroscopy system.

The XgjIA imaging system includes an X-ray tube 1 that emits X-rays toward the subject M, a high-voltage generator 2 that supplies the high voltage necessary for X-ray exposure to the X-ray tube 1, and a high-voltage generator that generates high voltage. An X-ray controller 3 that performs control is placed opposite the X-ray tube 1 with the subject M in between.
The camera is configured to include a film changer 4 that continuously feeds the line film F to the photographing position. Further, a continuous imaging device controller 5 is provided which controls feeding of the X-ray film F of the film changer 4 and also provides a timing signal for X-ray exposure to the X-ray controller 3.

In addition, the reference numeral 20 in the figure indicates X for the continuous imaging device controller 5.
This is an X-ray switch that outputs a radiography start signal.

The X-ray fluoroscopy system that performs fluoroscopy of angiographic images includes an X-ray image intensifier 6 that is placed behind the film changer 4 and converts the X-rays that have passed through the film changer 4 into a visible light image; an image pickup tube 7 that converts the output optical image of the intensifier 6 into an electric image and outputs a video signal obtained by scanning the electric image with an electron beam;
The camera control unit 8 (hereinafter abbreviated as CCU 3) mainly controls electron beam scanning of the image pickup tube 7.

A digital radiography circuit 9 (hereinafter abbreviated as DR circuit 9) converts the video signal output from the CCU 3 into a digital signal and performs various image processing.
It is configured to be displayed on the monitor 10 after being given to the computer.

Inside the DR circuit 9, in addition to an A/D converter 11 that converts an output video signal into a digital signal and a frame memo 2 serving as an image storage means for storing the digital video signal, Based on the vertical synchronization signal separation circuit 13 that separates and outputs the vertical synchronization signal, and the vertical synchronization signal and the X-ray exposure signal and X-ray cutoff signal output from the XwA controller 3, the electron beam of the image pickup tube 7 is used. Signal that controls scanning (hereinafter referred to as cathode blanking signal)
A cathode blanking circuit 14 is provided as an image readout control means for controlling image readout by outputting the image to the CCU 3.

Next, the operation of the above-described embodiment apparatus will be explained with reference to FIG. FIG. 2 is a signal waveform diagram of each part inside the device.

First, an X-ray imaging system and an attached X-ray fluoroscopy system are set at the region of interest of the subject M, and a contrast medium is injected into the blood vessel of the subject M. During this period, the cathode blanking signal d has already been output from the cathode blanking circuit 14 to the CCU 3, and an electron beam is generated from an electron gun (not shown) provided in the ink image tube 7. is in a state of forced suspension.

Next, the X-ray switch 20 sends the X-ray to the continuous imaging device controller 5.
When the radiography start signal is output, the continuous radiography device controller 5
causes the film changer 4 to set the X-ray film F at the imaging position, and also provides an X-ray exposure signal to the X-ray controller 3. The X-ray controller 3 receives the X-rays from the high voltage generator 2 in synchronization with the output timing of the X-ray exposure signal.
A high voltage is supplied to the ray tube 1, and X-rays are emitted from the X-ray tube 1 toward the subject M.

The X-rays that have passed through the subject M expose the X-ray film F, and then pass through the film changer 4 and reach the light incident surface of the X-ray image intensifier 6. The X-ray image intensifier 6 converts transmitted X-rays into a visible light image,
A light image is formed on the image plane of the image pickup tube 7. The image pickup tube 7 forms an electric image on the target surface by emitting charges corresponding to the brightness of the optical image to an output surface (target surface) provided therein.

At this time, the above-mentioned cathode blanking signal d still continues to be in the ON state, so the generation of the electron beam from the C1 image pickup tube 7 is stopped, and the read-out scanning of the electric image formed on the target surface is performed. Instead, charges forming an electrical image accumulate on the target surface during the X-ray exposure period.

Therefore, the output video signal e from the CCU 3 is output to the DR circuit 9 while maintaining the black level, as shown in FIG. That is, the A/D converter 11.

The video signal supplied to the monitor 10 via the frame memo 2 remains at the black level, and no fluoroscopic image is displayed on the monitor 10 during the X-ray exposure period.

Further, the output video signal e from the CCU 3 is given to a vertical synchronization signal separation circuit 13, where only the vertical synchronization signal a is extracted. The extracted vertical synchronizing signal a is output to the cathode blanking circuit 14.

When the required X-ray exposure period has elapsed, a timer circuit (not shown) provided in the X-ray controller 3 operates to stop the high voltage supply from the high voltage generator 2, and also to close the cathode blanking circuit. An X-ray cutoff signal C is output to 14.

The cathode blanking circuit 14 holds the applied X-ray cutoff signal C, and outputs the cathode blanking signal when the vertical synchronization signal a that continues to be input matches the held X&'X cutoff signal. Switch to the leaf F state for about l field period.

That is, when the next vertical synchronization signal a is input after the X-ray cutoff signal C is applied, the cathode blanking signal that has been continuously output to the CCU 3 is stopped for approximately one frame period.

As a result, the stoppage of generation of the electron beam in the image pickup tube 7 is released, and reading and scanning of the electric image accumulated on the target surface is started. Therefore, the level of the output video signal e from the CCU 3 corresponds to the amount of charge accumulated on the target surface of the image pickup tube 7 during the X-ray exposure period, and is converted into a digital signal by the A/D converter 11. After being converted, it is stored in the frame memory 12.

Since the frame memory 12 continues to output the stored fluoroscopic image data to a D/A converter (not shown), the input video signal f to the monitor 10 is obtained by one X-ray exposure, as shown in FIG. The video signal is repeatedly input to the monitor 10.
continues to display this.

In this way, during the XM exposure period, charges are accumulated in the imaging tube 7, so even if the imaging time is lengthened and the X-ray dose is reduced accordingly, it is sufficient to Since a bright image is obtained and the image continues to be displayed on the monitor, the flow of the contrast agent can be confirmed with greater accuracy.

In addition, according to the above-mentioned angiography imaging apparatus, it is possible to obtain both a subtraction image in which the blood vessel image is highlighted and an angiography image by performing differential processing on the mask image and the live image before and after injection of the contrast medium.

m+chi, when collecting the mask image, perform X-ray exposure without setting the X-ray film F in the film changer 4, and store the obtained fluoroscopic image in the frame memo January 2. Then, contrast agent is injected, X-ray film F is set, and the live image (
Angiogram) will be taken. At this time, the angiographic image is stored in the other frame memory (not shown) and recorded on the X-ray film F. By doing so, it is possible to obtain a digital subtraction image, and at the same time, it is possible to record and preserve the angiographic image on the X-ray film F.

This procedure may be reversed. That is, when an angiogram is taken, the angiogram is recorded on the X-ray film F and the re-storage medium of FLEMMEMO January 2, and after the angiogram is taken, X-rays are exposed again. , by storing it as a mask image in the other frame memory, it is possible to obtain both a subtraction image and an angiography image.

Effects of the G1 Invention As is clear from the above explanation, the angiography apparatus according to the present invention accumulates charges without reading out the images in the image pickup tube during the X-ray exposure period, and Since the accumulated images are read out after the exposure period ends, it is possible to reduce the X-ray dose by lengthening the imaging time during imaging, as when imaging the vascular system of the subject's head and abdomen. It is possible to provide bright (and easy-to-see) perspective images even under harsh conditions.

In addition, since the image output from the image pickup tube is stored, the fluoroscopic image obtained from - times of X-ray irradiation can be continued to be displayed until the next X-ray irradiation, and the flow of contrast medium can be monitored. It can be fully confirmed.

[Brief explanation of drawings]

1 and 2 relate to an embodiment of the present invention, with FIG. 1 being a block diagram showing a schematic configuration of an angiography apparatus, and FIG. 2 being a signal waveform diagram at various parts within the apparatus. 4... Film changer 6... X-ray image intensifier 7... Image pickup tube 8... CCU 10... Monitor 12... Frame memory 14... Cathode blanking circuit F... x-ray film

Claims (1)

[Claims] (1) Continuously feed the X-ray film to the imaging position and
An angiography system that performs radiography; an X-ray image intensifier receives transmitted X-rays that have passed through the X-ray film and converts them into a visible light image; this visible light image is captured and monitored by an imaging tube; In an angiography system equipped with a fluoroscopy system that displays blood vessel images, reading out images from the image pickup tube is prohibited during X-ray exposure to accumulate charge, and reading out the images after X-ray exposure is completed. What is claimed is: 1. An angiography imaging apparatus comprising: an image readout control means for performing the above-mentioned imaging tube; and an image storage means for storing the image read out from the imaging tube and outputting it to the monitor.