JP3189385B2 - X-ray fluoroscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical X-ray diagnostic apparatus and, more particularly, to an X-ray fluoroscopic apparatus capable of performing fluoroscopic image display and X-ray film photography on a television monitor in combination with an X-ray television system. About.

[0002]

2. Description of the Related Art An X-ray fluoroscopic apparatus is capable of converting an X-ray fluoroscopic image with an image intensifier, taking an image with a television camera, displaying the image on a television monitor, and taking an image on an X-ray film as necessary. You can do it. Normally, displaying on a monitor screen is called "perspective", and film shooting is called "shooting". The fluoroscopy is performed with a low X-ray dose, and a large dose of X-rays is emitted during imaging. Therefore, the high voltage generator is controlled by the X-ray control device, and the conditions of the X-ray tube are changed between fluoroscopy and radiography. The film is retracted during fluoroscopy, and the film is transported to the front of the image intensifier during shooting.

During photographing, in order to know in real time what kind of image was actually photographed on a film, a video signal of a fluoroscopic image at the time of photographing is generally sent to a monitor device and displayed. ing. In a conventional X-ray fluoroscopy apparatus, since an image pickup tube method is used as a television camera of an X-ray television system, a video signal of a captured image longer than a photographing time (about several tens of milliseconds) due to an afterimage effect. Was output, so that the photographed image could be observed on the monitor screen even during photographing.

[0004]

However, when a CCD camera is used as a television camera, there is no such after-image effect. Has a problem that observation on a monitor screen cannot be performed.

[0005] In view of the above, it is an object of the present invention to provide an X-ray fluoroscopic apparatus improved so that an image at the time of photographing can be displayed on a monitor screen even when a CCD camera is used.

[0006]

In order to achieve the above object, in an X-ray fluoroscopic apparatus according to the present invention, an X-ray image signal is obtained from a CCD camera and passed through a recursive filter circuit to reduce the afterimage effect. After being given, it is sent to the image display device to be displayed. The X-ray control device controls the high voltage generator that supplies a high voltage to the X-ray tube, controls the recursive filter circuit, and makes the recursive filter coefficient small during fluoroscopy and large during imaging.

[0007]

The recursive filter circuit performs noise reduction of the X-ray image signal and provides an afterimage effect. This afterimage effect changes according to the recursive filter coefficient, but the X-ray controller makes the recursive filter coefficient small during fluoroscopy and large during imaging. Therefore, a necessary noise reduction is performed at the time of fluoroscopy, and a large afterimage effect is provided at the time of photographing. Since the afterimage effect is large at the time of imaging, the X-ray image at the time of imaging can be displayed on the image display device for a certain period. This makes it possible to easily observe and confirm the photographed image on the image display device even during photographing.

[0008]

An embodiment of the present invention will be described below in detail with reference to the drawings. In FIG. 1, an X-ray fluoroscopy table 1 lays down a subject 2 and performs fluoroscopy and photographing of the subject 2. An image intensifier 6 and a CCD camera 7 are mounted for fluoroscopy.
An X-ray film (not shown) is transported to the front of the camera (the film transport mechanism is also omitted in the figure).

An X-ray tube 3 is arranged so as to face the image intensifier 6.
A high voltage is supplied from a high voltage generator 4 controlled by an X-ray controller 5, and X-rays are emitted from the X-ray tube 3 toward the subject 2.

At the time of fluoroscopy, the X-rays transmitted through the subject 2 enter the image intensifier 6 and are
, A video signal of an X-ray fluoroscopic image is obtained. This video signal is sent to the monitor device 9 via the image processing device 8, and a perspective image is displayed.

The image processing device 8 includes an A / D converter 81,
It comprises an adder 82, frame memories 83 and 84, and a D / A converter 85. The adder 82 and the frame memories 83 and 84 constitute a recursive filter circuit. That is, the video signal from the CCD camera 7 is sent one screen at a time (one frame at a time) and the A / D
The digital signal is converted by the converter 81 and sent to the adder 82. The adder 82 receives the digital image signal of one frame from the A / D converter 81 and the frame memory 8
4 and the digital image signal of one frame, the former has a coefficient of (1 / k), and the latter has a coefficient of 1- (1 / k).
And then add. The digital image signal of one frame after addition output from the adder 82 is stored in the frame memory 83 and also sent to the frame memory 84.

When digital image signals are sequentially output from the A / D converter 81 one frame at a time, the frame memory 8
4 is the 1 that was output from the adder 82 one frame before.
Since the digital image signal of the frame is stored, the digital image signal of this frame and the digital image signal of the current frame are added according to the above-described coefficient, and the frame memories 83 and 8 are returned.
4 is stored. Since this is repeated for each frame, a digital image signal of one frame including image components of several frames in the immediately preceding past is stored in the frame memory 83, and a recursive filter for giving an afterimage effect is formed. Will be. Increasing the recursive filter coefficient k increases the degree of inclusion of past images and increases the afterimage effect. Decreasing the coefficient decreases the degree of inclusion of past images and reduces the afterimage effect.

The digital image signal to which the afterimage effect has been applied is converted back to an analog signal by the D / A converter 85,
It is sent to the monitor device 9 and displayed.

At the time of fluoroscopy, a small dose of X-rays is emitted from the X-ray tube 3, and a video signal is obtained by the image intensifier 6 and the CCD camera 7. Since the CCD camera 7 has almost no afterimage, when the recursive filter is not used, the image displayed on the monitor device 9 has quantum noise that is conspicuous and difficult to see. Therefore, an afterimage effect is given by the recursive filter, but the recursive filter coefficient is set to be small. That is, at the time of this fluoroscopy, as shown in FIG. 2, a fluoroscopic signal is generated from the X-ray control device 5, which is sent to the image processing device 8, and the recursive filter coefficient becomes a preset small value. I have.

The reason why the recursive filter coefficient during fluoroscopy is reduced is to reduce blur caused by motion. That is, fluoroscopy is usually performed in order to track and confirm the barium (contrast agent) filling state of the stomach and the like in a circulatory examination or the like. This is because if is increased, blurring occurs and it becomes harder to see.

The fluoroscopy is performed as described above, and when barium comes to a target portion, the X-ray controller 5 is operated at a desired timing to instruct film photography. Then, as shown in FIG. 2, the fluoroscopic signal is turned off and the photographing signal is turned on. At this time, the X-ray film is conveyed to the front of the image intensifier 6 in the X-ray fluoroscopy table 1 and a large dose of X-ray
It is emitted from the wire tube 3. Since the fluoroscopic signal sent to the image processing device 8 is turned off and the imaging signal is turned on instead, the recursive filter coefficient k increases from small to large in synchronization with the video signal after the imaging signal has been turned on. As a result, even if there is no video signal from the CCD camera 7 at the time of photographing, the image can be switched to a preset large recursive filter coefficient, so that the afterimage effect increases, and the photographing image is displayed on the display screen of the monitor device 9. The image at that time is displayed for a certain period of time at an observable density.

When the photographing is completed within a short time, the photographing signal is turned off and the fluoroscopic signal is turned on again, so that the recursive filter coefficient is switched to a smaller one again in synchronization with the video signal. for that reason,
Conventional fluoroscopy can be performed in a state where the afterimage effect is small.

[0018]

As described above, according to the X-ray fluoroscopy apparatus of the present invention, when an X-ray television system using a CCD camera is employed, conventionally, an image disappears instantaneously from the monitor screen as the image is taken. The image at the time of shooting can be displayed on the monitor screen even while shooting,
Observation and confirmation of the photographed image can be easily performed.

[Brief description of the drawings]

FIG. 1 is a schematic view of an embodiment of the present invention.

FIG. 2 is a time chart for explaining the operation of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 X-ray fluoroscope 2 Subject 3 X-ray tube 4 High voltage generator 5 X-ray control device 6 Image intensifier 7 CCD camera 8 Image processing device 81 A / D converter 82 Adder 83, 84 Frame memory 85 D / A converter 9 Monitor device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-230785 (JP, A) JP-A-53-94819 (JP, A) JP-A-61-286843 (JP, A) 4824 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) A61B 6/00-6/14

Claims (1)

(57) [Claims] An X-ray tube for irradiating X-rays, an image intensifier into which X-rays transmitted through a subject are incident, and a CCD camera coupled thereto, and a film is provided in front of the image intensifier during photographing. X-ray fluoroscopy table for transporting film and taking a film
A recursive filter circuit for processing an image signal from a camera to give an afterimage effect, an image display device for displaying an image by an image signal passed through the recursive filter circuit, and a high voltage generator for supplying a high voltage to the X-ray tube And an X-ray control device that controls the high voltage generator, controls the recursive filter circuit, and makes the recursive filter coefficient small during fluoroscopy and large during radiography.