JPH0441555B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an X-ray television apparatus used for X-ray diagnosis.

[Technical background of the invention]

As is well known, conventional medical X-ray television equipment uses an image intensifier (hereinafter referred to as I.
I.) and converts it into a fluorescent image, and the fluorescent image is transmitted through an optical system to a television camera (hereinafter referred to as TV
The device is configured to take an image with a camera (referred to as a camera), send the video signal to a television monitor, and display it as an X-ray fluoroscopic image on the screen of the television monitor.

By the way, in the case of diagnosis of the circulatory system, etc., the output image (fluorescence image) of II is taken with a cine camera and the image is recorded and saved on cine film, but II is a type of vacuum tube and the X-ray input surface is circular. It is. Therefore,
An output image with a circular frame will be displayed on the output screen.

On the other hand, cine film has a rectangular frame with an aspect ratio of approximately 3:4 per frame, and in order to maintain image quality and capture the image to fill the entire screen as much as possible, the circular frame of the output image of II is set to one part of the cine film. Shoot in a manner that circumscribes the frame of the frame. Therefore, in this case, the portion of the image that extends beyond the frame of one frame of the cine film is not captured on the film.

However, so that the entire output image of II is displayed on the TV monitor screen, the circular frame of the output image is
The image is taken so that it fits within the frame of the rectangular display surface of the monitor.

That is, as shown in Figure 1a, the output image 1 of II is displayed in a circular frame, and this circular frame is
Make sure it fits on the rectangular display surface 2 of the TV monitor.
It is captured by the camera tube surface 3 of the TV camera.

When this is subjected to circle blanking processing to blank the outside of the circular frame and then presented to a TV monitor, the output image 1 of II is displayed so as to fit on the display surface 2 of the TV monitor, as shown in Figure 1b. .
Note that 2' is the actual display surface of the TV monitor.

On the other hand, in consideration of image quality and effective use of the film surface, cine films are designed as shown in Figure 2a.
II The circular frame of the output image 1 is imprinted on the film so that it circumscribes the frame 4 of the cine film.

Therefore, the angle of view of the film and the angle of view of the TV monitor will be different.

However, when performing cine photography, it is not possible to grasp from the image on the TV monitor the extent to which the cine film is photographed, so when performing X-ray television fluoroscopy, the angle of view shown in Figure 1 b is used, and cine photography is At times, a system has been proposed in which images are taken at four angles of view as shown in FIG. 2a and displayed on a cine film as shown in FIG. 2b.

This allows you to adjust the angle of view to suit your purpose by changing the scan size of the image pickup surface of the camera tube depending on the mode.
It uses a method of displaying images on a TV monitor, and will be referred to here as dual scan television.

FIG. 3 is a block diagram showing the configuration of this system.

In the figure, 21 is an image pickup tube, 22 is a deflection coil for scanning an electron beam that is applied to the imaging surface of the image pickup tube 21 to extract an electric latent image as a video signal, and 23 is a weak video signal output from the image pickup tube. A preamplifier 24 for amplifying the amplified video signal output from the preamplifier 23 corrects the shading (decreased amount of peripheral light) of the II output image led to the image pickup tube 21 and the shading in the optical system, and also corrects the periodic signal. 25 is an auto amplifier that performs gain control according to the level of the video signal processed by this process amplifier 24, M is a TV monitor, 26 is a perpendicular to the deflection coil 22 in the image pickup tube 21;
This deflection circuit 26 provides a horizontal deflection signal, and the deflection circuit 26 is provided with a vertical deflection setting device 26V and a horizontal deflection setting device 26H, which define the electron beam scanning range of the imaging surface of the imaging tube 21. . Each of the setting devices 26H, 26V has a pair of variable resistors R1, R2 and R3, R4, one of which is used for the X-ray fluoroscopy mode and the other for the cine imaging mode. Then, the resistance value is set so that the scanning range of the electron beam corresponds to each mode, and the output of the sawtooth wave signal generation circuit for deflection (not shown) is connected to the variable resistors R1 and R, respectively.
2, R3, and R4, the sawtooth wave current is obtained by a variable resistor corresponding to the selected mode, and is applied from the deflection circuit 26 to the deflection circuit 22 of the image pickup tube 21.
The electron beam will be controlled.

Therefore, each of the setting devices 26H and 26V is provided with an output switching switch SWH and SWV for selecting one of each pair of variable resistors. In the figure, relay RL1 is used as switches SWH and SWV.
A switch is used, and by opening and closing the foot switch FSW for turning on and off relay RL1, relay RL1 is turned on and off and a variable resistor is selected. Note that _Vcc is a power source for energizing relay RL1.

That is, in such a configuration, the setting device 26
H, 26V variable resistors R1 to R4 are connected to each other when foot switch FSW is off, that is, relay RL1
When foot switch FSW is off, R1 and R3 are selected via the normally closed contacts of switches SWH and SWV, and when foot switch FSW is on, that is, relay RL1 is on, R1 and R3 are selected via the normally open contacts of switches SWH and SWV. R2 and R4 are selected.

Therefore, the variable resistors R1 and R3 are used here for the X-ray fluoroscopy mode, and the variable resistors R2 and R
4 is used for cine shooting mode.

Therefore, R1 and R3 are set so as to obtain a deflection current in the scanning range of 2 as shown in FIG.
is adjusted in advance so as to obtain a deflection current in the scanning range 4 in FIG. 2a.

Now, if foot switch FSW is off, relay RL1 is off, so each setting device 26H,
26V variable resistors R1 and R3 are selected, and a sawtooth wave current having a current value corresponding to the resistance value is applied to the deflection coil 26 via the deflection circuit 26.

On the other hand, the image pickup tube 21 is not shown on its imaging surface.
The output image from II is guided and focused by an optical system. This imaging state is the same regardless of the mode.

This imaging state is as shown in FIG. 1a, and the image 1 on the imaging surface 3 remains on the imaging surface 3 as an electric latent image depending on the density distribution of the image.

As described above, in the X-ray fluoroscopy mode, the electron beam is deflected to scan the range indicated by 2 in FIG. That is, since the electric latent image is an image formed by electric charge, when the electron beam hits the electric latent image, a signal corresponding to the electric charge of that part is extracted as a video signal. This video signal is amplified by a preamplifier 23, further processed by a process amplifier 24, and then gain controlled by an autoamplifier 25 so that the entire II output image shown in FIG. 1b is displayed on a TV monitor M. It will be displayed as an image.

Also, in cine shooting mode, the foot switch FSW
By closing, relay RL1 turns on,
Since the normally open contacts of the switches SWH and SWV are closed, each setting device 26H and 26V are connected to the variable resistor R.
2, R4 will be selected. Therefore, R
2, a sawtooth wave current having a current value corresponding to R4 is applied to the deflection coil 22.

On the other hand, the image pickup tube 21 is not shown on its imaging surface.
The output image from II is guided and imaged by an optical system. This imaging state is the same as in the previous X-ray fluoroscopy mode, and is as shown in FIG. 2a.

Then, the deflection circuit 26 scans the range shown by 4 in FIG.
After passing through the preamplifier 23, process amplifier 24, and autoamplifier 25, the TV monitor M
given to. As a result, an image as shown in FIG. 2b is displayed on the TV monitor M.

This image is the same as the image on the cine film, so the operator can know what kind of image will be captured on the cine film.

Of course, even in X-ray fluoroscopy mode, the angle of view can be adjusted by closing the foot switch FSW.

By the way, in the case of such a dual scan method, the scanning area of the imaging surface of the image pickup tube 21 is switched and used, but the video signal output current of the image pickup tube 21 is determined when the amount of light incident on the image pickup tube 21 is the same. In this case, there is a characteristic proportional to the scanning area.

Here, if the image pickup tube 21 is scanned with the same electron beam current for each scanning area in the dual scan, on one side, the beam current will be appropriate, but on the other hand, the beam current will be too high or too low, resulting in S/N
The result is a low-resolution image with a poor ratio. In particular, when the beam current is set to be an appropriate beam current for the scanning area in the X-ray fluoroscopy mode, the current value of the electron beam of the image pickup tube 21 becomes excessive in the cine imaging mode. Therefore, in such a case, the resolution deteriorates, the image becomes difficult to see, and the excessive beam current value also adversely affects the life of the image pickup tube 21.

However, conventionally, when changing the scanning area, the current value of the electron beam of the image pickup tube is not changed.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances. When switching the electron beam scanning area of the image pickup surface of the image pickup tube in a dual scan type X-ray television apparatus, the present invention provides an appropriate electron beam current corresponding to the scanning area. The values should be changed in conjunction with each other so that the values are the same.
An object of the present invention is to provide an X-ray television device that can always obtain high-quality images with optimal resolution and can extend the life of an image pickup tube.

[Summary of the invention]

That is, in order to achieve the above-mentioned object, the present invention guides an optically converted image of an X-ray image to an image pickup tube and forms the image on the image pickup surface, scans the image pickup surface with an electron beam to obtain a video signal, and obtains a video signal from the image pickup tube. An X-ray television device that applies a signal to a television monitor and displays it as an image, and that the image pickup tube allows the electron beam scanning range of the imaging surface to be selected from a plurality of preset ranges of different widths according to the mode. Voltage setting means for setting the image pickup tube bias voltage that provides an appropriate beam current corresponding to each of the electron beam scanning ranges for each of the modes, and means for selecting a bias voltage corresponding to the selected mode from the voltage setting means. and the bias voltage of the image pickup tube is switched in accordance with the electron beam scanning range of the image pickup surface of the image pickup tube, which changes depending on the mode, so as to always maintain the optimum beam current value of the electron beam, which changes depending on the width and narrowness of the image pickup surface. be able to do so.

[Embodiments of the invention]

4 and 5 regarding one embodiment of the present invention.
This will be explained with reference to the figures.

FIG. 4 is a block diagram showing the configuration of the apparatus of the present invention, in which XT is an X-ray source, XC is an X-ray diaphragm provided on the X-ray emission port side of this X-ray source XT, and II is a subject P OP is an optical system that guides the output image of image intensifier II, and TC is an output image of II that is guided by this optical system OP. The image pickup tube 21 is a television camera unit that takes an image of
Built-in. The CNC is a cine camera that photographs the output image of II distributed by a light distributor, such as a prism, provided in the optical system OP. CC
is the TV camera controller, FSW is the foot switch for mode switching, M is the TV camera section TC
This is a TV monitor that displays images captured by.

The foot switch FSW is the same in function and use as the one shown in FIG.

The television camera controller CC controls the television camera section TC, and has a configuration as shown by CC in FIG.
Since it is exactly the same as that shown in the figure, the same reference numerals are given to the same parts as in FIG.

In the present invention, when the scanning area of the imaging surface of the image pickup tube 21 in the television camera section TC by the electron beam is switched in the X-ray fluoroscopy mode and the cine photography mode, an appropriate electron beam current value corresponding to the scanning area is determined. The feature is that it has a configuration that can be switched so that.

That is, for this purpose, a beam current switching setting device 51 shown in FIG.
The current value of the electron beam is controlled by applying it to the grid G1 to control the first grid bias voltage of the image pickup tube 21.

That is, the beam current switching setting device 51 is connected to the variable resistor R.
A series circuit of 5 and R6 is inserted between the negative DC power supply -V and the ground potential. Then, the movable terminal output of the variable resistor R5 is connected to the first grid G1 of the image pickup tube 21, and the movable terminal of the variable resistor R6 is connected to the connection point between R5 and R6. In addition, there is a short-circuit switch between the fixed terminals of variable resistor R6.
SWS is connected. This switch SWS uses the normally closed contact of the switch operated by the relay RL1, and is configured to short-circuit the variable resistor R6 in the X-ray fluoroscopy mode. Note that the cathode K of the image pickup tube 21 is grounded.

In this apparatus having such a configuration, selection of the X-ray fluoroscopy mode and the cine photography mode is performed on the television system side using the foot switch FSW. This is exactly the same as in the case of FIG. 3, but in this apparatus, the output of the beam current switching setter 51 is switched in response to a change in the scanning area of the imaging surface of the imaging tube 21, which changes due to mode switching.

That is, in the X-ray fluoroscopy mode, since the relay RL1 is deenergized, the switch SWS of the beam current switching setting device 51 is closed, and in the series circuit of resistors consisting of R5 and R6, only R5 is functioning. The potential -V applied to the series circuit of resistors is divided by the variable resistor R5. That is, a voltage V1 determined by using the movable terminal setting position of the variable resistor R5 as a voltage dividing point is applied to the first grid G1 of the image pickup tube 21. Also, in the cine shooting mode, relay RL1 is energized, switch SWS is opened, and variable resistor R6 is activated, so the resistance value of variable resistor R6 is added to the resistance value of R5, and at this time R5 A voltage value obtained by dividing -V at a voltage division ratio determined by the movable terminals of is applied to the first grid G1.

Since R6 is on the ground potential side, in the cine shooting mode where R6 is inserted, the beam current switch setting device 51
The movable terminal output of R5, which is the output of
It will approach V. The more negative the potential between the first grid G1 and the cathode K in the electron tube is, the more the flow of electrons is suppressed. The movement of electrons is suppressed compared to the mode.

Therefore, in the X-ray fluoroscopy mode, the movable terminal of the variable resistor R5 is set in advance so that the appropriate beam current value for that mode is given, and in the cine imaging mode, the appropriate beam current value for the cine imaging mode is set. By setting the movable terminal of the variable resistor R6 as shown in FIG. The image pickup tube 21 is scanned with an electron beam having a current value corresponding to the area.

Therefore, a video signal of an appropriate level is always obtained, and images with good S/N ratio and resolution can be obtained.In addition, since the beam current value is appropriate, deterioration of the image pickup tube 21 can be suppressed, resulting in a long service life. It is possible to aim for

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with appropriate modifications within the scope of the gist thereof.For example, in the above embodiments, dual scan (two different Although a system using a multi-scan method (having two or more different scanning areas) has been described above, a similar concept can be applied to a system using a multi-scan method (having two or more different scanning areas). Although mode switching has been described using a foot switch, other switches may be used, or a command signal for cine photography may be used.

In addition, since the voltage value for focusing the beam tends to vary slightly depending on the value of the beam current, a voltage switch configured as the beam current switch setting device 51 is used in combination to switch the focus voltage. You can do it like this.

In addition to the above-described configuration, the beam current switching setting device 51 may have a system in which a large number of independent voltage setting devices are arranged in parallel and the voltage setting device is selected according to the mode.

〔Effect of the invention〕

As described in detail above, the present invention guides an optically converted image of an X-ray image to an image pickup tube, forms an image on the image pickup surface of the tube, scans the image pickup surface with an electron beam, and provides the obtained video signal to a television monitor. In an X-ray television apparatus, the image pickup tube displays the electron beam scanning range of the imaging plane from a plurality of preset setting ranges of different widths according to the mode. Voltage setting means for setting a bias voltage of the image pickup tube that provides an appropriate beam current corresponding to the electron beam scanning range, and means for selecting a bias voltage corresponding to the selected mode from the voltage setting means, the voltage setting means changing depending on the mode. The bias voltage of the image pickup tube is changed according to the scanning range of the electron beam on the image pickup surface of the image pickup tube, so that the bias voltage of the image pickup tube can be changed so that the optimum beam current of the electron beam changes depending on the width and narrowness of the scanning range of the image pickup surface. Since the voltage can be switched, the imaging surface can be scanned with an appropriate beam current corresponding to the scanning area, and the video signal can be extracted at an appropriate level, resulting in high-resolution, high-quality images with a good S/N ratio. In addition, it is possible to provide an X-ray television device with excellent features such as no excessive beam current, no deterioration of the imaging surface, and the ability to extend the life of the imaging tube. can.

[Brief explanation of the drawing]

Fig. 1 and Fig. 2 are diagrams for explaining the display state of images by mode in a dual scan type device, and Fig. 3 is a schematic configuration diagram for explaining a conventional example of a dual scan type device. , FIG. 4 is a block diagram showing one embodiment of the present invention, and FIG. 5 is a configuration diagram for explaining details of the main parts thereof. 21...Image tube, 22...Deflection coil, 23...Preamplifier, 24...Process amplifier, 25...Auto amplifier, 26...Deflection circuit, 26H, 26V...Setting device, RL1...Relay, SWH, SWV, SWS...Switch, FSW... Foot switch, XT...X-ray source, I.
I....Image intensifier, OP...Optical system,
CNC...Cine camera, TC...TV camera department, CC
...Camera controller, M...TV monitor, 51
...beam current switching setter, G1...first grid,
K...Cathode.

Claims (1)

[Claims] 1. The optically converted image of the X-ray image is guided to the image pickup tube and focused on the image pickup surface, the image pickup surface is scanned with an electron beam to obtain a video signal, and this video signal is given to a television monitor to be displayed as an image. In addition, in an X-ray television apparatus in which the electron beam scanning range of the imaging surface can be selected from a plurality of preset ranges of different widths according to the mode, Voltage setting means for setting the image pickup tube bias voltage that provides an appropriate beam current corresponding to the range, and means for selecting a bias voltage corresponding to the selected mode from the voltage setting means are provided, and the image pickup tube bias according to the mode is provided. An X-ray television device characterized in that it gives the following: