JPH04135385A - X-ray radiographing device - Google Patents

Abstract

PURPOSE:To obtain the high-quality image of a reagent by providing a subtracter to execute a subtracting operation processing with the digital data of a mask image, D/A converter to convert the differential processed picture (subtraction image) data to an analog video signal, and monitor display to display the subtraction image. CONSTITUTION:A subtracter 11 executes the subtracting operation processing between the digital data of a live image and the data in a mask image memory 9 corresponding to this data. By this processing, the same data at the same positions of the live image and the mask image are excluded. Namely, the subtraction image after the subtraction processing becomes a picture excluding shading images caused by a bed 4 or the flaw of an X-ray image intensifier 2 or the like. A D/A converter 13 converts the subtraction image data to the analog video signal and when outputting the signal to a monitor display 14, the subtraction image is displayed. Thus, the picture to be displayed on the monitor display 14 is the high-quality picture having no unnecessary shading images and can be contributed for exactly diagnosing the picture.

Description

Detailed Description of the Invention A. Industrial Field of Application This invention relates to an X-ray fluoroscope that can capture an X-ray image transmitted through a subject with an X-ray television camera, CCD camera, etc. and display it on a monitor display. Regarding photographing equipment.

B. Prior Art Fluoroscopic imaging using this type of X-ray fluoroscopic imaging apparatus is performed as follows.

X-rays are emitted from the X-ray tube toward the subject, and an X-ray image intensifier placed opposite the X-ray tube transmits the X-ray image through the subject. Changes in X-ray intensity are interpreted as changes in brightness. Convert to a visible light image. An X-ray television camera (or
A CCD camera) captures the visible light image, converts it into a video signal, and sends it to an image processing system.

The image processing system digitizes the output video signal from the X-ray television camera using an A/D converter and stores it in an image memory, and also converts it into an analog video signal using a D/A converter.
The perspective image is displayed on a monitor display.

In addition, while maintaining the facing posture of the X-ray tube and X-ray image intensifier, they are moved in opposite directions along the body axis of the subject, and the fluoroscopic images taken during the movement process are added. In some cases, a tomographic image of the area at the center of movement may be taken.

Problems to be Solved by the C0 Invention However, in the above-mentioned X-ray fluoroscopic imaging device,
The X-ray image intensifier and
If there is a scratch on the beam television camera or the imaging table on which the subject is placed, the scratch will appear as an unnecessary shadow image on the captured image, making it difficult to distinguish it from the shadow image of the subject, making it difficult to use for diagnosis. When used as an image, it has the disadvantage of causing misdiagnosis.

In addition to the scratches mentioned above, there are also problems such as unevenness in the luminance of the X-ray image intensifier and burn-in on the imaging surface of the X-ray television camera (which occurs when high-brightness images are captured for a long time). Unnecessary shadow images caused by stains from contrast agents (barium, etc.) remaining on the imaging table can also cause misdiagnosis.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an X-ray fluoroscopic imaging device that can eliminate the above-mentioned unnecessary shadow images and obtain high-quality images of a subject. It is said that

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

That is, the present invention provides an X
An X-ray tube that emits rays, an X-ray image intensifier that converts an X-ray image transmitted through a subject into a visible light image, and an imaging means that captures the visible light image and generates a video signal. The X-ray fluoroscopic imaging apparatus includes an A/D converter that converts the video signal into digital data, and an image (mask) taken through the bed and the X-ray image intensifier while the subject is not lying supine. Difference calculation processing between the digital data of the image (live image) taken with the subject lying supine on the bed and the corresponding digital data of the mask image. The present invention is characterized in that it includes a subtractor that performs this, a D/A converter that converts differentially processed image (subtraction image) data into an analog video signal, and a monitor display that displays the subtraction image.

81 Effect According to the present invention, before performing live image capturing of the subject,
A mask image is taken through a bed and an X-ray image intensifier in the absence of a subject.

The mask image is converted into digital data by an A/D converter and stored in a mask image memory.

At this time, if there are scratches or the like on the head or the X-ray image intensifier, the mask image becomes a shadow image caused by them.

After photographing the mask image, the subject is placed supine on the bed and a live image is photographed.

The subtractor performs a difference calculation process between the digital data of the live image and the corresponding data in the mask image memory.

This process eliminates the same data at the same position in the live image and the mask image. In other words, the subtraction image after the difference processing is an image in which shadow images caused by scratches on the bed or the X-ray image intensifier are excluded.

The D/A converter converts the subtractive image data into an analog video signal and outputs it to a monitor display.

As a result, a subtraction image is displayed.

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 X-ray fluoroscopic imaging device.

In the figure, numeral 1 is an X-ray tube that emits X-rays toward the subject M, 2 is an X-ray image intensifier (X-ray 1.1) that converts a transmitted X-ray image into a visible light image G; 3 is X%91L
+ X that captures the output light image from 2 and outputs a video signal
A television camera 4 is a bed on which the subject M lies supine.

The X-ray tube 1 is configured to be movable in the body axis direction of the subject M by swinging the support arm 5.
The X-ray television camera 3 is moved horizontally by the moving mechanism 6.
They are configured to be movable in mutually opposite directions along the body axis of the subject M while maintaining a posture facing the wire tube 1.

The above configuration is the same as the conventional one, and not only fluoroscopic imaging but also tomography is possible.

Reference numeral 7 is an image processor that uses image processing technology to eliminate unnecessary shadow images that appear on captured images, such as scratches on the bed 4 and the imaging system (X-ray 1.12, X-ray television camera 3). An A/D converter 8 that converts the output video signal from 3 into a digital signal, that is, multivalued concentration data, a switch SW that switches the output light of the A/D converter 8, and a state in which the subject M is not in the bed 4. , that is, a mask image memory 9 that stores density data of an X-ray image (mask image) transmitted only through the bed 4 and the imaging system.
, the switch SW in response to a command from the console 15.
a control unit 10 that performs switching control and readout control of the mask image memory 9; a subtractor 11 that performs difference processing between a photographed image (live image) of the subject M and a mask image; and stores a difference processed image (subtraction image). The subtraction image memory 12 and the D/A converter 13 convert density data of the subtraction image into analog signals.

14 is a monitor display that displays a subtraction image.

Next, the operation of the above-mentioned device will be explained.

Normally, when the X-ray tube 1, the X-ray 1.12, and the X-ray television camera 3 are set at the imaging position, the subject M is imaged. Unnecessary shadow images (the above-mentioned mask images) caused by scratches, etc. are photographed.

From the operator (or X-ray technician) via the console 15,
When a mask image photographing command is given, the control unit IO switches the switch SW to the mask image memory 9 side. In this case, the control unit 10 does not perform a reading operation from the mask image memory 9. In this state, X-rays are emitted from the X-ray tube 1.

After passing through the bed 4, the X-rays enter the incident surface of the X-rays 1.12 and are converted into a visible light image. The X-ray television camera 3 scans the visible light image with an electron beam and outputs the generated one-dimensional video signal to the A/D converter 8. The A/D converter 8 samples continuous analog density values of the video signal at a predetermined period and converts them into multi-valued digital density data expressed in 8 bits, for example. The bit string of density data output from the A/D converter 8 is sequentially stored in each pixel of the mask image memory 9 via the switch SW.

FIG. 2(a) shows an example of a photographed mask image.

For the sake of explanation, it is assumed that there are scratches on the photocathode surfaces of XM1 and I2, and that stains of contrast medium (eg, barium, etc.) remain on the head 4. In Fig. 2, the symbol K indicates the wound caused by X-rays 1 and 12, and the symbol W indicates the stain caused by the contrast agent. After taking such a mask image, the operator (or
When a live image capturing command is given to the control section 1o via the control section 1o, the control section 10 switches the switch SW to the subtractor 11 side. In this state, the subject M is placed on the bed 4, and an image (live image) of the subject M is photographed in the same manner as the mask image described above.

That is, X-rays are emitted from the X-ray tube 1 toward the subject M. A live image transmitted through the subject M is sequentially converted into digital density data by an A/D converter 8, and is provided to a subtractor 11 via a switch SW. Here, an example of a live X-ray image is shown in FIG. 2(b). As shown in this figure, the live image is an image obtained by adding the previous mask image to the image transmitted through the subject M, that is, the shadow image of the subject M plus the X-ray 1
．． The shadow image due to the wound No. 12 and the stain of the contrast medium on the bed 4 overlap in the image, making it difficult to differentiate it from the shadow image of the lesion S during image interpretation.

Therefore, the control section 10 sequentially starts reading out the density data in the mask image memory 9 in synchronization with the sampling timing of the live image data by the A/D converter 8. The bit string of density data output from the mask image memory 9 is applied to a subtractor 11 . Similarly, A
The bit string of density data of the live image output from the /D converter 8 is also provided to the subtractor 11 .

In other words, the density data of each pixel of the mask image and the corresponding density data of each pixel of the live image are sequentially supplied to the subtractor 11, and the difference calculation process of the image density data is performed here. .

As a result of the difference calculation process, density data having the same value at the same position of the mask image and the live image are excluded, and other data become difference data. Therefore, the density data of the shadowed area caused by the X-ray 1.12 scratch appearing in the mask image and the contrast agent stain on the bed 4 are excluded, and only the density data transmitted through the subject M is subtraction image memo January 2.
is stored in

The density data stored in the subtraction image memo January 2 is sequentially read out and converted into an analog video signal by the D/A converter 13, and a subtraction image as shown in FIG. 2(C) is displayed on the monitor display 14. Is displayed.

In the above-mentioned embodiment, a description was given of normal fluoroscopic imaging, but unnecessary shadow images can be eliminated in the same way when taking a tomographic image of the subject M using this apparatus. .

That is, when taking a tomographic image, the X-ray tube 1 and the imaging system (X-ray 1.T2 and X-ray television camera 3) are moved in opposite directions along the body axis of the subject M. , so the mask image is also photographed in the same way,
Unnecessary shadow images at each imaging position are stored in a plurality of mask image memories. Then, a live image of the subject M is photographed, and the above-described subtraction processing is performed between the mask image and the live image corresponding to each photographing position to eliminate unnecessary shadow images. By adding up each subtraction image after exclusion, a clear tomographic image of the moving center region can be obtained.

Further, in the above-described embodiment, reading of data in the mask image memory 9 is started in synchronization with the sampling timing of the A/D converter 8, and a subtraction image from which unnecessary shadow images are eliminated is obtained in real time. However, a new live image memory is installed to store the live image, and after shooting, a subtraction image is created that eliminates unnecessary shadow images by performing differential calculation processing between the data in the live image memory and the data in the mask image memory. You may also obtain

Effects of the G1 Invention As is clear from the above explanation, the X-ray fluoroscopic imaging device according to the present invention is capable of photographing a mask image (unnecessary shadow image) through the head and the X-ray image intensifier in advance. Since the live image of the subject and the mask image are differentially processed and the subtraction image after the differential processing is displayed, unnecessary shadows caused by scratches on the bed, X-ray image intensifier, or imaging means are eliminated. Images can be eliminated by their differential processing.

Therefore, the image shown on the monitor display is
The result is a high-quality image without unnecessary shadow images, which can contribute to accurate image diagnosis.

[Brief explanation of the drawing]

1 and 2 relate to an embodiment of the present invention, in which FIG. 1 is a block diagram showing a schematic configuration of an X-ray fluoroscopic imaging device, and FIG. 2(a) is an example of a mask image; Figure 3) is an example of a live image, and Figure (C) is an example of a subtraction image. 1...X-ray tube 2...X-ray image intensifier 3...X-ray television camera 4...Head end...A/D converter
9...Mask image memory 11...Differentiator
13...D/A converter 14...Monitor display Patent applicant: Shimadzu Corporation

Claims (1)

[Claims] (1) An X-ray tube that irradiates X-rays toward a subject lying supine on a bed, an X-ray image intensifier that converts an X-ray image transmitted through the subject into a visible light image, and the visible light image. An X-ray fluoroscopic imaging apparatus comprising: an imaging means for capturing an image to generate a video signal; an A/D converter for converting the video signal into digital data; A mask image memory that stores digital data of an image (mask image) taken through an X-ray image intensifier, digital data of an image (live image) taken with the subject lying supine on the bed, and a subtractor that performs a difference calculation process with the digital data in the corresponding mask image memory, and a difference processing image (
1. An X-ray fluoroscopic imaging device comprising: a D/A converter that converts subtraction image data into an analog video signal; and a monitor display that displays a subtraction image.