JPH0614701B2 - X-ray television imaging device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention belongs to the technical field of diagnostic medical devices, and in particular,
It belongs to the technical field of an X-ray television imaging apparatus such as a digital fluorography apparatus or an X-ray fluoroscopic imaging apparatus.

[Technical background of the invention and its problems]

Conventionally, in an X-ray television imaging apparatus, it is general that an X-ray fluoroscopic image of a target site of a subject to be imaged is displayed on a display device, for example, a monitor, and the target site is confirmed by monitoring. For example, as shown in FIG. 1, the digital fluorography apparatus uses an image intensifier (hereinafter, referred to as an X-ray image obtained by transmitting X-rays emitted from the X-ray tube 12 through the subject P). It is also referred to as II.) 1. The input fluorescent screen converts the fluorescent image into a fluorescent image, and the fluorescent image is appropriately amplified and output as an optical image on the output fluorescent screen of I.I1. The television camera 3 captures an image through the tandem lens system 2), the video signal output from the television camera 3 is stored in the memory of the digital fluorography processor 5 via the camera controller 4, and then the digital fluorography processor. 5, the signal-processed video signal and the TV scanning signal are output to the TV monitor 6, the X-ray fluoroscopic image is displayed on the TV monitor 6, and the X-ray fluoroscopic image is recorded on the image recording device 7. ,
Alternatively, the multi-format camera 8 is configured to capture an X-ray fluoroscopic image on an X-ray film.

In addition, the digital fluorography apparatus uses the X-ray tube 12 for continuous operation in both the simple fluoroscopy mode and the fluoroscopy mode in which a video signal obtained by continuous X-ray exposure is processed as a digital signal. X-ray exposure is performed as follows. That is, the digital fluorography processor 5 outputs a control signal for controlling continuous X-ray exposure to the X-ray controller 10, and a high voltage is generated from the high voltage generator 11 by the control signal output from the X-ray controller 10. By continuously applying to the X-ray tube 12, the X-ray tube 12
X-rays are continuously emitted from.

Further, in the digital fluorography apparatus, in the fluoroscopic imaging mode that requires intermittent X-ray exposure and digital signal processing, intermittent X-ray exposure is performed as follows. That is, intermittent X from the digital fluorography processor 5
Outputs a control signal for controlling the radiation exposure to the X-ray controller 10,
The high voltage is intermittently applied to the X-ray tube 12 from the high voltage generator 11 by the rate signal output from the X-ray controller 10, so that the X-rays are intermittently emitted from the X-ray tube 12.

Further, in the digital fluorography device, as shown in FIG.
Although the indirect spot camera 15 and the I, I indirect cine camera 14 may perform the I, I indirect photographing, the fluoroscopic image is observed by the television camera 3 and the television monitor 6 even at the time of the I, I indirect photographing. .

Therefore, in the digital fluorography device, a simple fluoroscopic mode, a fluoroscopic imaging mode for I, I indirect imaging, a fluoroscopic imaging mode that requires continuous X-ray exposure or intermittent X-ray exposure and digital signal processing, etc. Therefore, the amount of light incident on the television camera 3 per unit time is different, and therefore the image output level from the television camera 3 is also different.

The amount of light incident on the television camera 3 per unit time also differs due to variations in conversion coefficients of I and I of the same type or differences in conversion coefficients of I and I of different types. Further, the amount of light incident on the television camera 3 per unit time also varies due to a decrease in the conversion coefficient with the aging of I, I and a change in the conversion coefficient due to switching of the input field diameters of I and I.

In order to perform optimum monitoring, the output level of the video signal from the TV camera 3 must always be constant. However, since the optimum X-ray exposure condition is determined according to the surgical method, it is not preferable to finely adjust the X-ray exposure condition in order to maintain the output of the television camera 3 at a constant level.

Therefore, the conventional digital fluorography device or X
Regarding the radiographic imaging apparatus, as shown in FIG. 3, a diaphragm 16 for varying the amount of light incident on the television camera 3 of an optical image in the X-ray optical system, and a diaphragm controller 13 for controlling the diaphragm 16.
In combination with (the same number as shown in FIG. 1), the diaphragm controller 13 adjusts the diaphragm 16 so that the amount of light incident on the television camera 3 per unit time becomes constant. Proposed by the applicant (see Japanese Patent Application No. 32311 in 1982).

However, if the diaphragm diameter of the diaphragm 16 is reduced to 1/2 or less of the aperture diameter of the secondary lens 19, the light passes through the primary lens 18, which is inserted between the primary lens 18 and the secondary lens 19. Photo pickup 20 for detecting the amount of light to be emitted
There is also a problem in that vignetting phenomenon occurs due to absorption and scattering of light due to, and defects occur in the optical image.

Further, there is a semi-transmissive mirror 17 as a light amount correction means for the television camera 3 when switching from the simple fluoroscopic mode to the fluoroscopic imaging mode by I, I indirect imaging.

However, since the light transmittance to the television camera 3 is limited to one type for the semi-transmissive mirror 17, even if the semi-transmissive mirror 17 can correct the light amount by mode switching, an indirect spot camera for gastric examination. By indirect spot camera for circulatory system and indirect cine camera for circulatory system
It is not possible to correct the amount of light incident on the television camera 3 per unit time based on the difference in each X-ray exposure condition in I, I indirect imaging. Therefore, even if a plurality of semi-transmissive mirrors 17 are arranged in order to enable such correction of the incident light amount, it is not practical due to the limitation of the capacity of the X-ray optical system, and the number of semi-transmissive mirrors 17 used. Is limited to two.

Further, in the digital fluorography device, per unit time to the television camera 3 for the fluoroscopic imaging mode by continuous X-ray exposure requiring digital signal processing and the fluoroscopic imaging mode by intermittent X-ray exposure requiring digital signal processing. The correction of the incident light amount has been conventionally performed by attaching a light attenuation filter to the semi-transmissive mirror 17.

However, such a correction means has a drawback that the correction of the amount of light incident on the television camera 3 per unit time at the time of I, I indirect shooting must be sacrificed.

In addition, there are variations in conversion coefficient between I and I of the same model, differences in conversion coefficient between I and I of different models, decrease in conversion coefficient due to aging of I and I, switching of input field diameter of I and I. The correction of the amount of light incident on the television camera 3 per unit time in accordance with the change in the conversion coefficient due to is performed by the auto iris control method.

However, in a digital fluorography device,
Along with the switching between the two modes, if the diaphragm 15 is changed by the auto iris control method and the diaphragm diameter is set near the upper or lower limit of the usable range of the diaphragm diameter, I, I
It becomes impossible to properly correct the light amount corresponding to the change in the conversion coefficient of.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and in an X-ray television imaging apparatus such as a digital fluorography apparatus and an X-ray fluoroscopic imaging apparatus, a difference in operative method, fluoroscopy, fluoroscopic imaging mode, conversion of I, I An X-ray television image capturing apparatus having an optical system capable of keeping the image output of the television camera always constant by adjusting the amount of light incident on the television camera per unit time, regardless of the difference in the factors due to various causes. It is intended to be provided.

[Outline of Invention]

In order to achieve the above-mentioned object, the X-ray television imaging apparatus of the present invention is an image that converts a transmitted X-ray image obtained by transmitting X-rays emitted from an X-ray tube through a subject into an optical image and outputs the image. An intensifier, an optical system provided at the output end of the image intensifier, having a primary lens and a secondary lens, and the primary lens on the opposite side of the image intensifier in the primary range. A light quantity detector arranged in the formed parallel light rays and detecting the quantity of light passing through the primary lens, and a plurality of light quantity detectors arranged so as to be able to move in and out in the parallel light rays between the light quantity detector and the secondary lens. A neutral density filter, a diaphragm arranged in a parallel light beam between the light amount detector and the secondary lens and having a variable diaphragm diameter, and an optical image output from the secondary lens of the optical system. That a television camera, such that the optical image of the predetermined amount to the television camera is inputted regardless of the change in the amount of light of an optical image output from the image intensifier, on the basis of an output from the light intensity detectors,
Control means for variably controlling the aperture diameter of the aperture in a range of a predetermined aperture value or more and for controlling the entrance / exit of the neutral density filter into / from the parallel light rays.

Example of Invention

FIG. 4 shows the configuration of an X-ray television image capturing apparatus, such as a digital fluorography apparatus, which is an embodiment of the present invention.

The digital fluorography device shown in FIG. 4 differs from the digital fluorography device shown in FIG. 1 in the following points.

That is, the primary lens 18 and I, I1 of the primary lens 18
A light quantity detector, such as a photo pickup 20 for detecting the quantity of light transmitted through the primary lens 18, and a secondary lens 19, and a diaphragm 21 for varying the quantity of light of an optical image. An optical system 23 having a plurality of optical attenuation filters 22-1, 22-2, ..., 22-n capable of entering and exiting the parallel rays formed by the next lens 18 and attenuating the light quantity of the parallel rays; An aperture controller 24 that outputs an aperture drive signal that controls the aperture diameter of the aperture 21 according to a control signal that is output from the fluorography processor 27, and a perspective mode and digital signal processing that are output from the digital fluorography processor 27. Depending on the difference between the fluoroscopic imaging mode by continuous X-ray exposure and the fluoroscopic imaging mode by intermittent X-ray exposure that requires digital signal processing, the plurality of optical attenuation filters 22-1, 22- Filter drive controller 25, which outputs a filter drive control signal in a cycle of 2, ..., 22-n into and out of a parallel light command signal, and a filter drive controller 2
, 22-n alternately or in a plurality of sheets at a time by a filter drive control signal output from the filter drive device 26-
26-n, and outputs the command signal to the filter drive control unit 25 and the aperture control unit 24 in accordance with various modes designated by a console box (not shown),
The command signal is sent to the aperture controller 24 based on the information about the amount of light passing through the primary lens 18 detected by the photo pickup 20, which is input through the automatic exposure controller 9 and the X-ray controller 10. And a digital fluorography processor 27 having a function of outputting.

The light attenuation filters 22-1, 22-2, ..., 22-n have different light transmittances and are configured to be replaceable. Further, the diaphragm 21 is for fine adjustment of the light quantity,
The light attenuation filters 22-1, 22-2, ..., 22-n are used for coarse adjustment of the light amount.

It is to be noted that, in FIG. 4, those denoted by the same numbers as those in FIG. 1 have the same functions as those shown in FIG.

Next, the operation of the above configuration will be described.

In the digital fluorography device shown in FIG. 4, the aperture diameter of the aperture 21 is an intermediate aperture value between the upper and lower limits in the usable range (for example, the upper limit is 20 and the lower limit is 0).
Then, the intermediate value is 10). By appropriately arranging the light attenuation filter 22 in the parallel rays, the output level of the output video signal of the television camera 3 is kept constant even if the amount of light transmitted through the primary lens 18 changes.

Here, for example, when the aperture diameter is 10 and the light transmittance of the light attenuation filter 22 is 100% (that is, the light attenuation filter is not inserted), the optimum state is set, and at this time, the light is transmitted through the primary lens 18 in the investment mode. When the light quantity is 100 and the output level of the obtained video output signal is 1, the diaphragm 21 and the light attenuation filter 22 when the light quantity changes are controlled as described below.

When switching to the fluoroscopic imaging mode by continuous X-ray exposure that requires digital signal processing, if the amount of light passing through the primary lens becomes 200, for example, one of the light attenuation filters 22 having a light transmittance of 50% is used as a parallel light beam. A command signal to be inserted into the filter driving controller 25 is input from the digital holography processor 27 to the filter driving controller 25.
5 outputs a filter drive control signal to the filter drive device 26-1, for example, and the filter drive device 26-1
Thus, the light attenuation filter 22-1 having a light transmittance of 50% is arranged in the parallel light beam, and the amount of light transmitted through the primary lens 18 is 2
00, the light attenuation filter 22 having a light transmittance of 50%
When -1, the video signal of level 1 is output from the television camera 3.

Further, when the conversion coefficient of I, I1 decreases to 4/5 due to aging, the photo pickup 20 determines that the primary lens 1
It is detected that the amount of light passing through 8 has decreased from 200 to 160, and the detection signal is transmitted via the automatic exposure control unit 9 and the X-ray controller 10 to the digital fluorography processor 2
When output to 7, digital fluorography processor 2
7 outputs a command signal to the aperture control unit 24, and the aperture drive signal output from the aperture control unit 24 opens the aperture value 10 of the aperture 21 to 1.118 times.
The amount of light passing through 1 is set to 200, and then the light transmittance is set to 50.
The amount of light is attenuated to 100 by the optical attenuation filter 22-1 of 100%, and as a result, the video signal of level 1 is output from the television camera 3.

Further, in the digital fluorography device equipped with dual I, I, in which I and I1 have two kinds of input visual field diameters (9 inches and 7 inches) and the conversion coefficient is reduced to 4/5 due to aging, the digital signal Continuous X that requires processing
In the fluoroscopic imaging mode by line exposure, when the field of view of 9 inches is switched to the field of view of 7 inches, the conversion coefficient of I and I1 drops to 49/81. When it is detected that the amount of light transmitted through the primary lens 18 has decreased to 160 × 49/81 and the detection signal is output to the digital holography processor 27, the command signal output from the digital holography processor 27 is input. The aperture value 10 of the aperture 21 is set to 1.437 by the aperture drive signal output from the aperture controller 24.
By opening it twice, the amount of light passing through the diaphragm 21 can be reduced to 2
00, and then the optical attenuation filter 22 having a light transmittance of 50%.
The light amount is attenuated to 100 by -1, and as a result, the video signal of level 1 is output from the television camera 3.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and it is needless to say that the invention can be appropriately modified and implemented within the scope of the gist of the invention. Nor.

The mode switching in the above-described embodiment was switching from the simple fluoroscopic mode to the fluoroscopic imaging mode by continuous X-ray exposure, but the fluoroscopic imaging mode by I, I indirect imaging, and intermittent X-ray exposure requiring digital signal processing. Even if the mode is switched to the fluoroscopy mode by the control of the diaphragm 21 without controlling the diaphragm 21 to an intermediate value between the upper and lower limit values within the usable range of the diaphragm diameter, for example, 1/2 or less, Fine adjustment and optical attenuation filters 22-1, 22-2, ... 22
By controlling the amount of light incident on the TV camera by the selection control of -n, the TV camera 3 is prevented while preventing the vignetting phenomenon.
The output level of the video signal can be made constant.

〔The invention's effect〕

According to the present invention described in detail above, in an X-ray Deliver imaging apparatus such as a digital fluorography apparatus or an X-ray fluoroscopic imaging apparatus, a simple X-ray mode, a fluoroscopic imaging mode by I, I indirect imaging, continuous X requiring digital signal processing. The X-ray exposure mode and the X-ray exposure mode, which require digital signal processing, can change the X-ray exposure conditions, and the conversion factors of I and I of different models Even if the amount of light that passes through the primary lens changes due to the difference in I, the deterioration of the conversion coefficient due to aging deterioration of I, and the change of the conversion coefficient due to the switching of the input field diameter of I, I The diameter can be variably controlled within the range of the specified aperture value, the entrance / exit of the neutral density filter into the parallel light is controlled, and the incident light quantity per unit time to the TV camera is made constant, While preventing development can also be a constant video output of the television camera. By making the video output of the television camera constant, the digital image processing in the digital fluorography processor can be appropriately performed, and a perspective image without deterioration can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing a conventional digital fluorography device, FIG. 2 is a block diagram showing a main part of a conventional digital fluorography device for performing conventional I, I indirect photography, and FIG. 3 is a conventional X-ray television photography. Block diagram showing the optical system of the device,
And FIG. 4 is a block diagram showing an embodiment of the present invention. 1 ... Image intensifier, 3 ... TV camera, 12 ... X-ray tube, 18 ... Primary lens, 19 ... 2
Next lens, 21 ... Aperture, 22-1, 22-2, ..., 22-n ... Optical attenuation filter, 23 ... Optical system.

Claims (1)

[Claims] 1. An image intensifier that converts a transmitted X-ray image obtained by transmitting X-rays emitted from an X-ray tube through an object into an optical image and outputs the image, and an image intensifier of the image intensifier. The optical system is provided at an output end and has a primary lens and a secondary lens, and the optical system is arranged in a parallel light beam formed by the primary lens on the opposite side of the primary lens from the image intensifier. A light amount detector for detecting the amount of light transmitted through the primary lens,
A plurality of attenuating filters arranged so as to be able to move in and out in a parallel light beam between the light amount detector and the secondary lens, and an aperture arranged in the parallel light beam between the light amount detector and the secondary lens A diaphragm with a variable diameter, a television camera that captures an optical image output from the secondary lens of the optical system, and a constant amount for the television camera regardless of the change in the light amount of the optical image output from the image intensifier. Based on the output from the light quantity detector, the diaphragm diameter of the diaphragm is variably controlled within a range of a predetermined aperture value or more so that the optical image of the light quantity is input, and the light enters or leaves the parallel rays of the neutral density filter. And a control means for controlling
Line television shooting device.