JPH0779384A - X-ray diagnostic device - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an X-ray diagnostic apparatus for obtaining an X-ray fluoroscopic image of a subject having a predetermined brightness regardless of the thickness of the subject. An X-ray diagnostic apparatus for obtaining an X-ray fluoroscopic image of a subject 20 having a predetermined brightness by changing the output of the X-ray generator 30 by automatic brightness adjustment. The adjusting means 70 is provided for adjusting the brightness of the fluoroscopic image when the output reaches the maximum value. Further, the adjusting means includes at least one of an iris aperture, a gain of the TV camera, and a sensitivity of the image intensifier.
It is characterized by comprising a means for adjusting one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray diagnostic apparatus, especially X-ray diagnostic apparatus.
The present invention relates to adjustment of brightness of an X-ray fluoroscopic image of a subject obtained by a line diagnostic apparatus.

[0002]

2. Description of the Related Art An X-ray diagnostic apparatus includes an X-ray generator for irradiating a subject with X-rays and an image intensity which is a conversion means for detecting the X-rays transmitted through the subject and converting them into an optical image. It is equipped with a fire and a TV camera for inputting the optical image through an optical system and converting the optical image into a video signal. By displaying the output of the TV camera on a display device such as a TV monitor, It is configured to obtain a fluoroscopic image of the specimen.

In the above X-ray diagnostic apparatus, a technique called automatic brightness adjustment (hereinafter referred to as "ABC control") is known. In this ABC control, the amount of light incident on the TV camera is detected by some means (generally, a photomultiplier, a video signal, etc.), and the detected amount of light is fed back to the X-ray controller to control the X-ray generator. This is a technique for adjusting the output. By this ABC control, a constant video signal can be obtained regardless of the thickness of the subject.

As described above, the level of the video signal of the TV camera differs because the absorption amount of X-rays differs depending on the thickness of the subject, but the output of X-rays is adjusted by the ABC control so that the video is always constant. You can get a signal.

However, since the amount of X-ray absorption increases as the thickness of the subject increases, the ABC control causes
X-ray output increases. If the thickness of the subject increases further, X
The output of the line generator further increases, and finally the output of the X-ray generator reaches the upper limit (maximum output). When the output of the X-ray becomes maximum, the output of the X-ray generator cannot be further increased. Therefore, when an object having a thickness larger than that is attempted to be seen through, the video signal from the TV camera is set to a predetermined value. I can't reach the level. So in this case,
Since an image having a predetermined brightness cannot be obtained on the TV monitor, the X-ray fluoroscopic image becomes darker than a normal image, which causes a trouble in diagnosis.

[0006]

As described above, conventionally, when the subject is very thick, the output of the X-ray generator becomes maximum before the video signal reaches a predetermined level. However, in this case, the obtained X-ray fluoroscopic image becomes darker than usual, which causes a problem in diagnosis.

The present invention has been made under the above circumstances, and an object thereof is to provide an X-ray diagnostic apparatus for obtaining an X-ray fluoroscopic image of a subject having a predetermined brightness regardless of the thickness of the subject. And

[0008]

The present invention has taken the following means in order to solve the above problems. According to the present invention, an X-ray generator that irradiates an object with X-rays, a conversion unit that detects the X-rays that have passed through the object and converts it into an optical image, and the optical image is input via an optical system. An X-ray diagnostic apparatus for obtaining an X-ray fluoroscopic image of a subject having a predetermined brightness by changing the output of the X-ray generator by automatic brightness adjustment. An adjusting means was provided for adjusting the brightness of the X-ray fluoroscopic image when the X-ray output from the generator reached the maximum value.

In the above X-ray diagnostic apparatus, the adjusting means comprises means for adjusting at least one of the aperture of the iris, the gain of the TV camera and the sensitivity of the converting means.

[0010]

As a result of taking the above-mentioned means, the following effects occur. When X-ray fluoroscopy is performed under the maximum output of the X-ray generator, when the video signal is lower than the reference signal level (reference video signal), for example, measures such as increasing the gain of the TV camera are taken, Since the video signal is amplified to the reference signal level, the monitor image with the same brightness as in the case of a subject of normal thickness can be obtained even in the case of a thick subject that could not be diagnosed because the monitor image was dark in the past. It is possible to improve the diagnostic effect.

Further, even when a thick subject that would make the X-ray fluoroscopic image dark in the prior art is entered, the X-ray fluoroscopic image does not become dark as described above, so that the previously unseen portion becomes visible. Therefore, the diagnostic accuracy of the doctor or X-ray technician can be improved. Also, X on the monitor
Since the fluoroscopic image does not become dark, it is not necessary to operate the contrast of the monitor, the diagnosis time is shortened, and the burden on the operator is reduced.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An X-ray diagnostic apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an X-ray diagnostic apparatus according to an embodiment of the present invention. FIG. 1A shows the overall configuration, and FIG. 1B shows the optical system. In this embodiment, by adjusting the gain of the TV camera,
A case of obtaining an X-ray fluoroscopic image of a subject having a constant brightness will be described.

In FIG. 1A, the X-ray controller 10 is
The X-ray irradiation conditions such as the energy of the X-rays irradiated to the subject 20 and the irradiation time are output. The X-ray generator 30 irradiates the subject 20 with X-rays based on the output of the X-ray controller 10. The X-rays that have passed through the subject 20 enter the input surface of an image intensifier 40 (hereinafter referred to as “II”) that is a conversion means, and the I.I. I. At 40 it is converted to an optical image. This optical image is input to the TV camera 60 via the optical system 50. The TV camera 60 converts the input optical image into a video signal and outputs it. This video signal is T
It is input to the V camera controller 70 and displayed on the TV monitor 80.

As shown in FIG. 1B, the optical system 50 has two lenses 51 and 52 and two lenses 51 and 52.
It is composed of an iris 53 arranged between. Further, the optical system 50 includes a photo lens 55 between the iris 53 and the lens 52. This Photomaru 55 is an I.D. I.
The amount of light input from 40 to the optical system 50 is measured. The measured value of the photomultiplier 55 is input to the ABC controller 90. The ABC controller 90 outputs a signal for controlling the output of the X-ray generator 30 (hereinafter referred to as “ABC signal”) to the X-ray controller 1.
0 and the TV camera gain controller 100. The X-ray controller 10 controls the output of the X-ray generator 30 based on the ABC signal, and when the output of the X-ray generator 30 is maximized, the TV camera gain controller 100 controls the TV.
Outputs camera control signal. TV camera gain controller 1
00 outputs a TV camera gain control signal to the TV camera controller 70 based on the ABC signal and the TV camera control signal.

The operation of the X-ray diagnostic apparatus of the present invention constructed as above will be described. If the output of the X-ray generator 30 is less than the maximum output, the normal A
The BC control keeps the X-ray fluoroscopic image at a predetermined brightness. In this case, the video signal level is used as the reference level,
The ABC signal output from the ABC controller 90 is referred to as “reference A
BC signal ”. Here, the ABC signal is usually given as a DC voltage value.

When a thick subject enters, the amount of light incident on the photomultiplier 55 decreases and the level of the ABC signal decreases. Then, the X-ray controller 10 causes the ABC signal from the ABC controller 90 to cause the current ABC signal (hereinafter,
It operates to increase the output of the X-ray generator 30 until the "measured ABC signal") is at the level of the reference ABC signal. When the subject becomes thicker, the ABC controller 90 outputs an ABC signal to the X-ray controller 10 so as to further increase the output of the X-ray generator 30. Here, if the output of the X-ray generator 30 reaches the maximum output before the ABC signal reaches the reference ABC signal, the X-ray generator 3 is no longer used.
Since the output of 0 cannot be increased, the X-ray fluoroscopic image displayed on the TV monitor 80 is conventionally dark.

According to the present invention, when the output of the X-ray generator 30 reaches the maximum output, the video signal is increased by increasing the gain of the TV camera 60 or the like so that a predetermined video signal can be obtained. Therefore, the X-ray fluoroscopic image displayed on the TV monitor does not become dark.

Now, a procedure for controlling the gain of the TV camera 60 to obtain a predetermined video signal will be described. First, a TV camera control signal indicating that the output of the X-ray generator 30 is maximum is input from the X controller 10 to the TV camera gain controller 100. The TV camera gain controller 100 is
It does not operate without this TV camera control signal.

Next, the TV camera gain controller 100
The difference between the reference ABC signal and the measured ABC signal output from the ABC controller 90 is detected, and the gain of the TV camera 60 is increased by a certain magnification. Measurement ABC signal and reference A
The relationship between the difference from the BC signal and the gain increasing rate of the TV camera 60 is set in advance in the system as shown in FIG. 2, for example. In FIG. 2, the vertical axis represents the gain increase rate of the TV camera, and the horizontal axis represents the measured ABC signal and the reference AB.
The difference from the C signal is shown. As shown in FIG. 2, for example, when the difference between the measured ABC signal and the reference ABC signal is 1V,
A TV camera gain control signal for increasing the gain of the TV camera by 1.5 is transmitted from the TV camera gain controller 100 to the T
It is output to the V camera controller 70. That is, the gain increasing rate of the TV camera is determined so that the video signal obtained as a result of increasing the gain becomes the same level as the reference video signal, and the TV camera gain control signal for controlling the increasing rate is the TV camera gain control signal. It is output to the controller 70.
The TV camera controller 70 increases the gain of the TV camera to a predetermined gain based on the TV camera gain control signal.

According to the procedure described above, even when the subject becomes thick and the X-ray output becomes maximum, the X-ray fluoroscopic image of desired brightness is displayed on the TV monitor. Further, when the subject becomes thin, the ABC signal increases, the difference between the measured ABC signal and the reference ABC signal disappears, and the output of the X-ray generator 30 starts to decrease from the maximum output, the X-ray controller 10 turns on the TV. The output of the camera control signal is stopped, the TV camera gain controller 100 stops operating, and the gain of the TV camera 60 becomes the normal gain. That is, the normal ABC control operation is returned to.

As described above, in the present invention, even under the maximum output of the X-ray generator, when the video signal is smaller than the reference level (that is, the reference video signal), for example, the gain of the TV camera is increased. Since the video signal is amplified to the standard level, the monitor image with the same brightness as in the normal case can be obtained even for a thick subject that could not be diagnosed because the monitor image was dark in the past. Can be raised.

Further, even when a thick subject such that the X-ray fluoroscopic image becomes dark is entered, since the X-ray fluoroscopic image does not become dark as described above, the previously unseen portion becomes visible. The diagnostic accuracy of the doctor or X-ray technician can be improved. Further, since the X-ray fluoroscopic image on the monitor does not become dark, it is not necessary to operate the contrast of the monitor, the diagnosis time is shortened, and the burden on the operator is reduced.

The present invention is not limited to the above embodiment. In the above embodiment, the image of the predetermined brightness is obtained by increasing the gain of the TV camera 60, but the image of the predetermined brightness may be obtained by adjusting the iris. In addition, I.D. I. It is also possible to obtain an image with a predetermined brightness by increasing the sensitivity of 40.

In addition, the gain adjustment of the TV camera 60, the iris 53 adjustment, and the I.D. I. It is also possible to obtain an image having a predetermined brightness by appropriately combining the sensitivity adjustments of 40.

In the above embodiment, the reference AB
Although the relationship between the difference from the C signal and the gain increase rate of the TV camera 60 is shown by a straight line, it may not necessarily be a straight line.
Of course, various modifications can be made without departing from the scope of the present invention.

[0026]

According to the present invention, the following effects can be obtained. When X-ray fluoroscopy is performed under the maximum output of the X-ray generator, when the video signal is lower than the reference signal level (reference video signal), for example, measures such as increasing the gain of the TV camera are taken, Since the video signal is amplified to the reference signal level, the monitor image with the same brightness as in the case of a subject of normal thickness can be obtained even in the case of a thick subject that could not be diagnosed because the monitor image was dark in the past. It is possible to improve the diagnostic effect.

Furthermore, in the conventional case, even when a thick subject such that the X-ray fluoroscopic image becomes dark is entered, the X-ray fluoroscopic image does not become dark as described above, so that the previously unseen portion can be seen. Therefore, the diagnostic accuracy of the doctor or X-ray technician can be improved. Also, X on the monitor
Since the fluoroscopic image does not become dark, it is not necessary to operate the contrast of the monitor, the diagnosis time is shortened, and the burden on the operator is reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an X-ray diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a difference from a reference ABC signal and a gain increase rate of a TV camera.

[Explanation of symbols]

10 ... X-ray controller, 20 ... Subject, 30 ... X-ray generator,
40 ... Image Intensifier (II), 5
0 ... Optical system, 51 and 52 ... Lens, 53 ... Iris,
55 ... Photomul, 60 ... TV camera, 70 ... TV camera controller, 80 ... TV monitor, 90 ... ABC controller, 1
00 ... TV camera gain controller.

Claims (2)

[Claims] 1. An X-ray generator for irradiating a subject with X-rays,
The X-rays transmitted through the subject are detected and converted into an optical image, and a TV camera that inputs the optical image through an optical system and converts it into a video signal is provided. In an X-ray diagnostic apparatus that obtains an X-ray fluoroscopic image of a subject with a predetermined brightness by changing the output of the X-ray generator, when the X-ray output from the X-ray generator reaches a maximum value, X An X-ray diagnostic apparatus comprising an adjusting means for adjusting the brightness of a fluoroscopic image. 2. The optical system includes an iris, and the adjusting means comprises means for adjusting at least one of the aperture of the iris, the gain of the TV camera, and the sensitivity of the converting means. The X-ray diagnostic apparatus according to Item 1.