JPH07272892A - X-ray television device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain an X-ray television device capable of displaying a fluoroscopic image adjusted to a predetermined luminance from the beginning of fluoroscopy on a monitor TV. [Structure] A memory (22) for storing the high voltage applied to the X-ray tube adjusted by the automatic brightness adjustment mechanism during X-ray exposure.
And a fluoroscope current generator (14) that creates an optimum tube current corresponding to the applied high voltage, and a high voltage and fluoroscope current generator (14) stored in the memory (22). And a memory (21) for obtaining a filament current from the optimum tube current, which preheats the X-ray tube filament with the filament current obtained by the memory (21), and the memory (2
The high voltage stored in 2) was applied to the X-ray tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray television apparatus, and more particularly to an X-ray television apparatus having an automatic brightness adjusting mechanism for keeping the brightness of a fluoroscopic image displayed on a monitor TV constant.

[0002]

2. Description of the Related Art In this type of X-ray television apparatus, the brightness (brightness) of a fluoroscopic image displayed on a monitor TV during fluoroscopy.
A transparent brightness automatic adjustment mechanism is provided to keep the brightness constant. X-ray television systems do not show X-rays.
At the time of non-irradiation of the radiation, a heating current is applied to the filament of the X-ray tube so that the filament is not exposed to the X-ray to preheat the filament. In this state, when the X-ray irradiation switch (fluoroscopic switch) is pressed for fluoroscopy, a predetermined high voltage that is set in advance is applied to the X-ray tube and X-ray irradiation is started. The X-ray transmitted through the object is converted into a visible light image by the image intensifier, converted into a video signal by the television camera connected to the image intensifier, and the transmitted image of the object is displayed on the monitor TV. .

On the other hand, the luminance of the transmitted image displayed on the monitor TV is compared with a luminance proportional signal (detection signal) from a camera control unit (hereinafter referred to as CCU) and a preset luminance reference signal, and the former is The optimum values of the tube voltage and the filament heating current change so as to match the latter, depending on the subject, and the brightness of the perspective image displayed on the monitor TV is maintained at a constant value determined by the brightness reference signal.

[0004]

However, the conventional X-ray television apparatus has the following problems.

That is, each time the fluoroscopy switch is pressed, X-ray irradiation is performed by applying a preset tube voltage to the X-ray tube in which the filament is preheated with a predetermined preheating current value. Starting, in other words, at the start of fluoroscopy, X-ray exposure is started with a fixed tube voltage and filament heating current (preheating current value). Since the current is controlled, it takes time to control to the optimum tube voltage value and the optimum filament heating current value at which a predetermined brightness can be obtained, and there is a drawback that a fluoroscopic image whose brightness is adjusted cannot be displayed from the beginning of fluoroscopy. .

This means that a surgical X-ray television apparatus used in the field of surgery in which the X-ray exposure is frequently turned on / off, and once a second for the purpose of reducing the exposure dose.
X-rays are radiated in about 00 msec, the transmission image at the time of X-ray irradiation is recorded in the video memory, and is recorded in the video memory while the X-rays are stopped until the next X-ray irradiation is made. This is a particular problem in the intermittent pulse fluoroscopy device that reproduces the captured image.

In view of the above, it is an object of the present invention to provide an X-ray television device capable of displaying a perspective image whose brightness is controlled from the beginning of the perspective on a monitor TV.

[0008]

In order to achieve the above object, the present invention provides a storage means for storing a high voltage controlled by an automatic brightness adjustment mechanism so that a predetermined brightness can be obtained during X-ray exposure. A means for calculating the tube current for the stored high voltage and a means for calculating the filament current of the X-ray tube based on the stored high voltage and the calculated tube current are provided. It is characterized in that the X-ray tube filament is preheated and the high voltage stored in the storage means is applied to the X-ray tube during the next X-ray irradiation.

[0009]

The storage means is controlled so that the tube voltage adjusted by the brightness automatic adjustment mechanism during X-ray exposure, that is, the brightness proportional signal from the CCU matches the brightness reference signal according to the subject, and is stable. After that, the high voltage applied to the X-ray tube is stored as the optimum tube voltage. The means to calculate the tube current is
The optimum tube current flowing in the X-ray tube corresponding to the optimum tube voltage is calculated. The means for calculating the filament current calculates the optimum filament current from the optimum tube current stored in the storage means and the optimum tube current calculated by the tube current calculation means, and holds the value.

Therefore, when the fluoroscopic switch is released and the X-ray exposure is completed, the optimum tube voltage adjusted so as to obtain the desired brightness at the end of the fluoroscopy and the optimum preheating filament current corresponding to the optimum tube current are stored. Will be retained. That is, at the end of the fluoroscopy, the tube voltage controlled to match the brightness reference signal, the respective optimum values of the tube voltage controlled to match the brightness reference signal and the filament current corresponding to the tube current are held, The filament is preheated with this filament current value.

As a result, when the fluoroscopy switch is pressed to start fluoroscopy, X-ray irradiation is started with the tube voltage and tube current at the time of the previous fluoroscopy termination, and these values are obtained at the time of the previous fluoroscopy termination. Since the obtained value is the optimum value for the subject, the tube voltage and the tube current (filament current) are adjusted so as to match the brightness reference signal in a short time even if the state of the object changes. Therefore, the brightness of the transmission image displayed on the monitor TV is quickly stabilized, and the perspective image adjusted to a predetermined brightness can be observed from the beginning of the perspective.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an embodiment of the present invention will be described below with reference to the drawings. Figure 1
FIG. 1 is a block diagram showing the configuration of an embodiment of an X-ray television device according to the present invention. When a high voltage is applied to the X-ray tube from the high voltage generator (4), X-rays are emitted from the X-ray tube. The X-rays that have passed through the subject are captured by an incident phosphor screen of an image intensifier (hereinafter referred to as II), converted into a visible light image, and output to the output phosphor screen. This I.D.
I. The visible light image displayed on the output phosphor screen of the
An image is formed on the image pickup surface of the image pickup tube (19) of the television camera through the primary lens (10) and the secondary lens (11).

The visible light image formed on the image pickup surface of the image pickup tube (19) in the transparent state is a CCU (camera control unit) (40)
A visible light image is displayed on the reading monitor (48) by the method, and a luminance proportional signal (39) is created and output to the X-ray controller (44). The brightness of the visible light image of this monitor (48) is controlled by the X-ray controller (4
Controlled by 4). That is, the brightness of the visible light image is CC
U (40) detects it as a luminance proportional signal (39), which is fed back to the high voltage and filament heating current applied to the X-ray tube through the X-ray controller (44) to adjust the X-ray intensity. First, the standard fluoroscopic condition, that is, the fluoroscope voltage reference signal (45) and the filament preheating signal (75) are respectively fed from the D / A converter (62) and D / A converter (60) of the microcomputer (26). It is being output.

When the X-ray exposure signal (43) is off, the switch S1 is turned on and the integrator (16) composed of the OP amplifier, the resistor R1 and the capacitor C1 is turned off,
At this time, the output ΔV1 of the integrator (16) is zero, one input of the adder (17) is zero, and the other input is a D / A converter.
It is the fluoroscope voltage reference signal (45) from (62). Therefore, the output of the adder (17), that is, the fluoroscopy tube voltage signal (46) has the value of the fluoroscopy tube voltage reference signal (45). Similarly, the switch S2 is turned on, and the integrator (78) including the OP amplifier, the resistor R2, and the capacitor C2 is also turned off.
At this time, the output ΔV2 of the integrator (78) is zero, one input of the adder (79) is zero, and the other input is a D / A converter.
It is the filament preheat signal (75) from (60). Therefore, the output of the adder (79), that is, the filament heating signal (80) is also the value of the filament preheating signal (75).

Next, when an X-ray exposure button (not shown) is pressed, the X-ray exposure signal (4
3) is fed to the high pressure generator (4). First, the fluoroscopy tube voltage starts from the value of the fluoroscopy tube voltage reference signal (45). As described above, the luminance proportional signal (39) is input from the CCU (40) to one input of the error amplifier (15) of the X-ray controller (44).
The luminance reference signal (41) is input to the other input of the error amplifier (15), and the difference between the luminance proportional signal (39) and the luminance reference signal (41) is amplified and integrated into the output of the error amplifier (15). Input to (16). The X-ray exposure signal (43) is applied to the switch S of the integrator (16).
It is also given to 1. When the switch S1 is turned off, the integrator (16) starts operating, and the output ΔV1 of the integrator (16)
Is fed to one input of the adder (17). On the other hand, the fluoroscope voltage reference signal (45) at the other input and this ΔV1 are added by the adder (17) to form a fluoroscope voltage signal (46).

The transparent tube voltage signal (46) is a tube voltage control circuit (18).
A high voltage corresponding to the fluoroscopic tube voltage signal (46) is applied to the X-ray tube from the high voltage generator (4). The applied high voltage is detected by the high voltage generator (4), fed back to the tube voltage control circuit (18), and controlled to be maintained at the fluoroscopic tube voltage signal value. The fluoroscopy tube voltage signal (46) is also given to the fluoroscopy tube current generator (14), and the fluoroscopy tube current signal (76) corresponding to the fluoroscopy tube voltage is supplied to one of the error amplifiers (77) as shown in FIG. It is output to the input. The tube current flowing through the X-ray tube is detected by the high voltage generator (4) and the fluoroscopic tube current measured value signal (81) is input to the other input of the error amplifier (77). Error amplifier (7
At the output of 7), the difference between the fluoroscopy tube current signal (76) and the fluoroscopy tube current measurement value signal (81) is amplified and input to the integrator (78).

The output ΔV2 of the integrator (78) is the error amplifier (7
It is an integration of the error between the fluoroscope current signal (76) which is the output of 7) and the fluoroscope current measurement value signal (81), and is added to the filament preheating signal (75) by the adder (79). It is fed back to the filament heating signal (80). If the measured value of the fluoroscope current changes and matches the fluoroscope current signal (76),
The output of the error amplifier (77) also becomes zero, and the input of the integrator (78) becomes zero, so the integration operation stops. In this way, feedback control is performed so that the fluoroscopy tube current signal (76) and the fluoroscopy tube current measurement value signal (81) become equal, and the fluoroscopy tube current measurement value becomes equal to the set value.

The output ΔV1 of the integrator (16) is the error amplifier (15).
Output, the error between the luminance proportional signal (39) and the luminance reference signal (41) is integrated, and is added to the fluoroscopy tube voltage reference signal (45) by the adder (17) to obtain the fluoroscopy tube voltage signal (46 ) Feedback. When the fluoroscope voltage changes appropriately and the luminance proportional signal (39) and the luminance reference signal (41) match, the output of the error amplifier (15) also becomes zero and the input of the integrator (16) becomes zero, so the integration The operation stops. Thus, the brightness proportional signal (3
Feedback control is performed so that 9) and the brightness reference signal (41) are equal to each other, and the brightness of the perspective image is kept constant. The fluoroscopic tube voltage signal (46) is also given to the A / D converter (61) to read the fluoroscopic tube voltage signal (46) and store it in the memory (22).

The fluoroscope voltage signal is previously stored in the memory (20).
The value of the fluoroscope current corresponding to (46) is stored as shown in FIG. The memory (20) reads the value of the fluoroscopy tube current corresponding to the read-out fluoroscopy tube voltage signal (46) from the fluoroscopy tube current signal (7).
6) give. As shown in FIG. 3, the memory (21) stores in advance a filament preheating current value FiA according to the fluoroscopic tube voltage FKV and the fluoroscopic tube current FmA. The filament preheating current value corresponding to the fluoroscopic tube voltage and the fluoroscopic tube current is read from the memory (21) and the D / A converter (6
The filament preheating current value signal (75) is output from (0). This value matches the current filament heating signal (80) value. When the X-ray exposure button is released, the X-ray exposure signal goes low, the high voltage is cut off from the high-voltage generator (4), and X-ray generation stops, and the final fluoroscope voltage value is stored in the memory (22). Will be remembered.

The final filament heating signal (80) is D / A
The filament preheating current value signal (75) is output from the converter (60), and the filament of the X-ray tube is preheated with the filament heating current value at the end of the fluoroscopy. When the X-ray exposure button (not shown) is pressed again and the X-rays are emitted, the brightness of the fluoroscopic image is kept optimal depending on the previous site / position of the subject, and the fluoroscopic voltage and the fluoroscopic current are maintained. X-rays are generated from the filament heating current value. Therefore, the brightness of the fluoroscopic image is quickly and optimally stabilized. The data of the filament preheating current value stored in the memory (21) is measured at several points with the fluoroscopic tube voltage and fluoroscopic tube current as parameters in the combination of the actual device and the X-ray tube. Is calculated by an interpolation method or the like.

[0021]

[Modified Example]

1) Not only the configuration in which the data obtained in advance is stored in the memory (21) and is read out by the set values of the fluoroscope voltage and the fluoroscope current, only the measurement data of several points and the calculation program (23) Also, when the fluoroscopy tube voltage and the fluoroscopy tube current are set together, the set values of the fluoroscopy tube voltage and the fluoroscopy tube current are calculated by the arithmetic program (23) from the data of several points using the microcomputer. Alternatively, the filament preheating current value may be calculated according to the above. 2) The filament characteristics vary greatly depending on the X-ray tube.
If it is necessary to store the filament characteristics for each wire tube, set the fluoroscope voltage at several points with the fluoroscope voltage setting device (54), and after stabilizing, measure the filament heating signal (80) and It may be stored in the memory (21) by the preheating current setting device (90). 3) Although the luminance signal is obtained from the CCU, it may be optically extracted from the output phosphor screen of the image intensifier.

[0022]

According to the X-ray television apparatus of the present invention, the time until the brightness of the transmission image displayed on the monitor TV stabilizes is shortened, and a perspective image adjusted to a predetermined brightness from the initial perspective can be displayed. . Therefore, it is extremely useful if the present invention is applied to a surgical X-ray television apparatus in which fluoroscopy is frequently turned on / off, and X-rays are emitted about once a second for the purpose of reducing the exposure dose. It is possible to stabilize the brightness of the transmission image displayed on the monitor TV even when the intermittent pulse irradiation is performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a fluoroscopy tube voltage and a fluoroscopy tube current stored in a memory (20) of FIG.

FIG. 3 is a characteristic diagram showing a relationship between a fluoroscopy tube voltage, a fluoroscopy tube current, and a filament heating current stored in a memory (21) of FIG.

[Explanation of symbols]: High-voltage generator: X-ray tube
: Subject: Image intensifier
: Optical system: Iris 10: Primary lens 1
1: Secondary lens 13: Light distributor 14: Fluorescent tube current generator 15: Error amplifier 16: Integrator 1
8: Tube voltage control circuit 19: Imaging tube 20, 21, 22, 23: Memory 39: Luminance proportional signal 40: CCU 4
1: Luminance reference signal 42: Density setting device 43: X-ray exposure signal 4
4: X-ray controller 45: Fluorescent tube voltage reference signal 46: Fluorescent tube voltage signal 4
7: Video signal adder 48: Monitor TV

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideki Fujii 1 Kinohara Kuwahara-cho, Nishinokyo, Nakagyo-ku, Kyoto City Shimadzu Sanjo Factory

Claims (1)

[Claims] 1. A high voltage applied to an X-ray tube and an X-ray tube so that a transmitted X-ray of a subject due to X-ray exposure is detected and a fluoroscopic image of a predetermined brightness is obtained on a monitor TV based on the detected value. In a X-ray television device adapted to control a tube current flowing through the storage means, storage means for storing the controlled high voltage, means for calculating a tube current for the stored high voltage, and storage in the storage means. Means for calculating a filament current flowing through the X-ray tube filament on the basis of the calculated high voltage and the calculated tube current, and preheating the X-ray tube filament with the calculated filament current and performing the next X-ray exposure. An X-ray television apparatus characterized in that a high voltage stored in the storage means is applied as a tube voltage to an X-ray tube during shooting.