JP3028771B2 - X-ray television equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an X-ray television apparatus, and more particularly to an X-ray television apparatus having an automatic brightness adjustment function.

[0002]

2. Description of the Related Art Conventionally, in an X-ray television apparatus,
The X-ray image transmitted through the subject is converted into a visible light image by an image intensifier, and is converted into a video signal by a television camera coupled to the image, and the transmitted X-ray image of the subject is displayed on a monitor. This type of X-ray television apparatus usually has an X-ray television that keeps the luminance of the fluoroscopic image on the monitor constant even when the fluoroscopic position moves or the thickness of the subject changes.
An automatic brightness adjusting means for controlling the line output is provided.
The brightness automatic adjustment means adjusts the X-ray irradiation dose by changing the fluoroscopic tube voltage and the fluoroscopic tube current (filament heating current), and controls the camera control unit (hereinafter referred to as CCU).
Is controlled to match the luminance proportional signal from
The brightness of the line image is kept constant.

At this time, automatic luminance control is performed by changing the fluoroscopic tube voltage FKV and the fluoroscopic tube current FmA on the curve shown in FIG.
The see-through condition is moved along a predetermined FKV-FmA characteristic so that the dose changes and the luminance is kept constant. In the conventional apparatus, a curve (FKV-FmA characteristic) of the fluoroscopic tube voltage and the fluoroscopic tube current as shown in FIG. 6 is formed by an operational amplifier and a diode circuit, and the characteristic of the fluoroscopic image is determined by this.

[0004]

In fluoroscopic diagnosis of the circulatory system used in interventional radiography for treating narrowing of blood vessels and aneurysms while performing angiography mainly with fluoroscopy, the fluoroscopic tube voltage is used. Is required to increase the fluoroscopy tube current and increase the dose to obtain a high-contrast fluoroscopic image. In addition, when used for esophageal imaging of the gastrointestinal tract, a lung field with low X-ray absorption is required. Since these are included in the fluoroscopic field, the fluoroscopic tube voltage is set to be high, and the fluoroscopic tube current is set to be low, and a fluoroscopic image having a wide dynamic range is required.

As described above, at the time of automatic brightness adjustment, it is necessary to control the fluoroscopic tube voltage and the fluoroscopic current so as to obtain a fluoroscopic image according to the diagnostic site of the subject and the diagnostic purpose. However, in a conventional X-ray television apparatus, there is only one curve (FKV-FmA characteristic) between the fluoroscopic tube voltage and the fluoroscopic tube current obtained by the operational amplifier and the diode.
There has been a problem that the fluoroscopic conditions (fluoroscopic tube voltage and fluoroscopic tube current) cannot be controlled so as to obtain a fluoroscopic image with a constant brightness according to the diagnostic site / diagnosis purpose.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide an X-ray television apparatus having an automatic brightness adjustment function capable of controlling a fluoroscopic condition so as to obtain a fluoroscopic image according to a diagnosis purpose.

[0007]

In order to achieve the above object, in an X-ray television apparatus according to the present invention, means for providing a fluoroscopic tube voltage-fluoroscopic current characteristic in automatic brightness adjustment is controlled by a controlled tube. It is characterized in that it is a writable storage means in which a fluoroscopic tube current is read using a voltage value as an address.

[0008] According to this configuration, the diagnosis part and the storage part are stored in the storage means.
According to the purpose of diagnosis, it is possible to write and store a fluoroscopic tube voltage-fluoroscopic tube current characteristic by which automatic luminance control can be performed so as to obtain a fluoroscopic image suitable for the diagnostic purpose. For example, when used in interventional radiography to treat narrowing blood vessels and aneurysms while performing angiography mainly with fluoroscopy, set the fluoroscopic tube voltage low and the fluoroscopic tube current high, The data (characteristics) of the fluoroscopic tube voltage and the fluoroscopic tube current shown in FIG. When the fluoroscopy operation is performed, the fluoroscopic tube voltage is adjusted by the brightness automatic adjustment function, the tube voltage value is changed to a digital value, and the digital tube is stored in a storage means (memory) that can read and write the digital value at an address. The current is read, converted to an analog value and output as a fluoroscopic tube current value.

With respect to a change in luminance due to a change in the thickness of the subject or the like, the luminance is adjusted while changing the fluoroscopic conditions on the curve of the fluoroscopic tube voltage and the fluoroscopic tube current shown in FIG.

As a result, a fluoroscopic image with good contrast can be obtained in which the fluoroscopic tube voltage is lowered and the fluoroscopic tube current is increased to increase the dose. Similarly, when performing gastrointestinal esophagography of the gastrointestinal tract, the fluoroscopic tube voltage shown in FIG.
The fluoroscopic tube current is set lower, and the data (characteristics) of the fluoroscopic tube voltage and the fluoroscopic tube current shown in FIG. 4 suitable for this are written in a readable and writable memory. By performing the fluoroscopy, a fluoroscopic image with a wide dynamic range is obtained, and the luminance is adjusted while changing the fluoroscopic conditions along the characteristics shown in FIG. In this way, a fluoroscopic image suitable for the diagnostic site / diagnostic purpose is obtained.

[0011]

FIG. 1 is a block diagram showing the configuration of an X-ray television apparatus according to the present invention.
An embodiment of the present invention will be described. High pressure generator 4
When a high voltage is applied to the X-ray tube 5, X-rays are emitted from the X-ray tube 5. The X-ray transmitted through the subject 6 is captured by an image intensifier 7 (hereinafter, referred to as an II) and converted into a visible light image and output to an output fluorescent screen. The output fluorescent screen of the II Is formed on the imaging surface of the imaging tube 19 of the television camera through the primary lens 10 and the secondary lens 11 of the optical system 8. The imaging is performed on the imaging surface of the imaging tube 19 in a transparent state. The visible light image is read by a CCU (camera control unit) 40, the visible light image is displayed on a monitor 48, and a luminance proportional signal 39 is created and output to the X-ray controller 44.

The brightness of the visible light image on the monitor 48 is controlled by the X-ray controller 44. That is, the luminance of the visible light image is detected by the luminance proportional signal 39 of the CCU 40, and this is fed back to the tube voltage applied to the X-ray tube 5 and the filament heating current via the X-ray controller 44 to adjust the X-ray intensity. You. Reference numeral 65 denotes a central processing unit (hereinafter referred to as a CPU) which operates according to a program written in a program memory 20 connected to a bus line 31.
The operation memory 50, the data memory 21, and the mode selector 55 are connected.

The data memory 21 stores data of a fluoroscopic tube voltage signal 46 and a fluoroscopic tube current signal 76 as shown in FIGS. 2, 3 and 4 for each of various modes. Operation memory 50
Is a memory that has two sets of address ports and data ports for one memory and that can connect bus lines from two directions. The first address port and data port are CPU
Connected to 65. The second address port is A / D
Connected to the output from converter 47. The second data port is connected to the input of the D / A converter 51. CP
The contents of the memory can be rewritten from U65, and A / D
The contents of the memory can be read from the output from the converter 47. The mode selector 55 selects a fluoroscopic mode according to the diagnosis site and purpose.

The data is read into the CPU 65 via the bus line 31,
The data of the fluoroscopic tube voltage and the fluoroscopic tube current are read out from the data memory 21 in accordance with the read fluoroscopic mode, and are written into the operation memory 50 as the fluoroscopic tube current value as data with the fluoroscopic tube voltage value as an address.

When the fluoroscopic mode of the circulatory system fluoroscopy is selected, data as shown in FIG. 2 is displayed. When the fluoroscopic mode of the gastrointestinal esophagography is selected, the data as shown in FIG. 3 is displayed. Is written to the operation memory 50. First, the fluoroscopy tube voltage reference signal 45 and the filament preheating signal 75, which are the fluoroscopy conditions at the start, are supplied to the D / A converter 62 and the
It is output from the / A converter 60. Next, the operation of the above configuration will be described for each function.

(Fluorescent tube voltage control 1) When the X-ray irradiation 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 the fluoroscopic tube voltage reference signal 45 from the D / A converter 62. Therefore, the output of the adder 17, that is, the fluoroscopic tube voltage signal 46
Is the value of the fluoroscopic tube voltage reference signal 45.

(Heating Circuit) Similarly, the switch S2 is turned on, and the integrator 78 composed of the OP amplifier, the resistor R2 and the capacitor C2 is turned off.
The output ΔV2 of 78 is zero, one input of the adder 79 is zero, and the other input is the filament preheating signal 75 from the D / A converter 60. Therefore, the output of the adder 79, that is, the filament heating signal 80 also has the value of the filament preheating signal 75. Next, when an X-ray emission button (not shown) is pressed, the X which is high only during X-ray emission is set.
The line exposure signal 43 is provided to the high voltage generator 4.

(Fluorescent tube voltage control 2) First, the fluoroscopic tube voltage starts from the value of the fluoroscopic 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. A luminance reference signal 41 is input to the other input of the error amplifier 15,
The difference between the luminance proportional signal 39 and the luminance reference signal 41 is amplified at the output of the error amplifier 15 and input to the integrator 16. Further, the X-ray irradiation signal 43 is also supplied to the switch S1 of the integrator 16. When the switch S1 is turned on, the integrator 16 starts operating, and the output ΔV1 of the integrator 16 is given to one input of the adder 17. The other input fluoroscopic tube voltage reference signal 45 and ΔV1 are added by the adder 17 to form a fluoroscopic tube voltage signal 46. The tube voltage signal 46 is a tube voltage control circuit.
A high voltage corresponding to the fluoroscopic tube voltage signal 46 is applied from the high voltage generator 4 to the X-ray tube 5. The applied high voltage is detected by the high voltage generator 4 and fed back to the tube voltage control circuit 18 to become a fluoroscopic tube voltage signal value.

(Calculation of fluoroscopic tube current) The fluoroscopic tube voltage signal 46 is
Further, it is given to an A / D converter 47 of the fluoroscopic tube current generator 14 and converted into a digital value. This value becomes the address value of the memory 50, and a fluoroscopic tube current value corresponding to the fluoroscopic tube voltage as shown in FIG. 2 is read out, converted into an analog value by the D / A converter 51, and formed as a fluoroscopic tube current signal 76. It is output to one input of the error amplifier 77. To the other input of the error amplifier 77, a tube current flowing through the X-ray tube 5 is detected by the high-voltage generator 4, and a fluoroscopic tube current measured value signal 81 is input. The difference between the fluoroscopic tube current signal 76 and the fluoroscopic tube current measured value signal 81 is amplified at the output of the error amplifier 77 and input to the integrator 78.

(Fluorescent tube current control) Output ΔV2 of integrator 78
Is an output of an error amplifier 77 that outputs an error between the fluoroscopic tube current signal 76 and the fluoroscopic tube current measured value signal 81, and is added to the filament preheating signal 75 by the adder 79 to obtain the filament heating signal 80. Will be fed back. When the measured value of the fluoroscopic tube current changes and coincides with the fluoroscopic tube current signal 76, the output of the error amplifier 77 also becomes zero and the integrator
Since the input of 78 becomes zero, the integration operation stops. In this way, feedback control is performed so that the fluoroscopic tube current signal 76 and the fluoroscopic tube current measured value signal 81 become equal, and the fluoroscopic tube current becomes a set value.

(Perspective luminance control) Output ΔV1 of integrator 16
Is an output of the error amplifier 15, which is obtained by integrating an error between the luminance proportional signal 39 and the luminance reference signal 41, is added to the fluoroscopic tube voltage reference signal 45 by the adder 17, and is fed back to the fluoroscopic tube voltage signal 46. . When the fluoroscopic tube voltage changes appropriately and the luminance proportional signal 39 and the luminance reference signal 41 match, the output of the error amplifier 15 becomes zero and the input of the integrator 16 becomes zero, so that the integration operation stops. Thus, the luminance proportional signal 39
And the luminance reference signal 41 are equalized, and the luminance of the fluoroscopic image becomes a reference value.

When the luminance changes due to a change in the thickness of the subject or the like, the fluoroscopic tube voltage and the fluoroscopic current change to maintain the luminance of the fluoroscopic image at a constant value as described above. At this time, the see-through condition moves on the curve of the see-through tube voltage and the see-through tube current shown in FIG. In this curve, the fluoroscopic tube current is suppressed and the fluoroscopic tube current is set to be large. Therefore,
A fluoroscopic image with good contrast suitable for fluoroscopic diagnosis of a circulatory system used in interventional radiography or the like for treating a narrowed blood vessel or an aneurysm while performing angiography mainly with fluoroscopy is obtained.

The same applies when the fluoroscopy mode of esophageal angiography of the digestive tract system in FIG. 4 is selected. FIG. 5 is a curve of a fluoroscopic tube voltage and a fluoroscopic tube current according to the distance (FID) between the X-ray tube focal point and the image intensifier. When this mode is selected, the fluoroscopic conditions are plotted on the curve corresponding to the FID. Will move. In the data memory 21, an optimal value is obtained by an experiment or the like, and a fluoroscopic tube current corresponding to the fluoroscopic tube voltage signal shown in FIGS. 3, 4 and 5 is obtained by using a fluoroscopic tube voltage setter 54 and a fluoroscopic tube current setter 53. The value of is input in advance.

In the above embodiment, the luminance signal is obtained from the video signal. However, the output of the image intensifier may be optically detected by a mirror or a prism and a photomultiplier. Good.

The following are conceivable embodiments of the present invention. Conversion means for converting a transmitted X-ray of a subject into a visible light image, means for converting the visible light image into a video signal, means for displaying a visible light image from the video signal, and conversion of a visible light image from the video signal. Means for detecting luminance, integrating means for integrating the difference between the luminance signal and the luminance reference signal, means for changing the tube voltage applied to the X-ray tube based on the integrated signal, and based on the tube voltage A fluoroscopic unit having a calculating means for calculating a tube current flowing through the X-ray tube, a calculating means for calculating a filament current flowing through the filament of the X-ray tube based on the tube voltage and the tube current, and a means for changing the filament current In the automatic brightness adjusting device, a calculating means for calculating a tube current flowing through the X-ray tube based on the tube voltage includes means for converting the tube voltage into a digital value, and flowing the digital value into the X-ray tube as an address value. And writable memory means for reading the tube current, read tube current value perspective automatic brightness adjustment device characterized by comprising a means for converting an analog value.

[0026]

According to the X-ray television apparatus of the present invention, the following effects can be obtained.

1) According to the X-ray television apparatus of the present invention, the optimum combination of the fluoroscopic tube voltage and the fluoroscopic tube current can be stored and selected according to the application site and purpose of the fluoroscopic diagnosis. In the case of fluoroscopic diagnosis of the circulatory system used for interventional radiography, which treats blood vessel narrowing and aneurysms while performing angiography, set the fluoroscopic tube voltage low and raise the fluoroscopic current. A high-contrast fluoroscopic image that increases the dose is obtained,
In addition, when used when performing gastrointestinal esophagography of the digestive tract system, the fluoroscopic tube voltage is set high, the fluoroscopic tube current is set low, the dynamic range is wide, and the lung field etc. are good. A perspective image can be obtained, and a favorable perspective image according to each case can be obtained.

2) Different fluoroscope voltage and fluoroscope current curves are stored for different distances, and a communication function is added to add a distance between the focus of the X-ray tube of the fluoroscopic table and the image intensifier. If the above information is obtained, it is also possible to change the curves of the fluoroscopic tube voltage and the fluoroscopic tube current based on the difference in distance, which has not been performed at all, and to perform more optimal fluoroscopic automatic adjustment.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a fluoroscopic tube voltage and a fluoroscopic current in a circulatory system.

FIG. 4 is a characteristic diagram showing a relationship between a fluoroscopic tube voltage and a fluoroscopic current in an esophagus of a digestive tract system.

FIG. 5 is a characteristic diagram showing a relationship between a fluoroscopic tube voltage and a fluoroscopic current according to a distance between an X-ray tube focal point and an image intensifier.

FIG. 6 is a characteristic diagram showing a relationship between a conventional tube voltage and a tube current.

[Explanation of symbols]

4: High voltage generator 5: X-ray tube 6: Subject 7: Image intensifier 8: Optical system 9: Iris 10: Primary lens 11: Secondary lens 14: Transparent tube current calculator 15: Error amplifier 16: Integration 17: Adder 18: Tube voltage control circuit 19: Image pickup tube 20: Program memory 21: Data memory 39: Luminance proportional signal 40: CCU 41: Luminance reference signal 43: X-ray exposure signal 44: X-ray controller 45 : Fluoroscopic tube voltage reference signal 46: fluoroscopic tube voltage signal 47: A / D converter 48: monitor 50: operation memory 51: D / A converter 53: fluoroscopic tube current setting device 54: fluoroscopic tube voltage setting device 55: mode Setting device 60: D / A converter 62: D / A converter 65: CPU 74: Filament heating circuit 75: Filament preheating signal 76: Fluorescent tube current signal 77: Error amplifier 78: Integrator 79: Adder 80: Filament heating signal 81: Fluorescent tube current measurement signal

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-272892 (JP, A) JP-A-8-23477 (JP, A) JP-A-1-230344 (JP, A) JP-A-2- 123699 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 7/18 H05G 1/26

Claims (1)

(57) [Claims] 1. A luminance of a transmitted X-ray image of a subject is detected, and an X-ray output (tube voltage, tube current) is determined by a comparison output of the luminance signal and a reference luminance signal into a predetermined fluoroscopic tube voltage-fluoroscopic tube current characteristic. In the X-ray television apparatus which is controlled on the basis of the above, generation of the fluoroscopic tube voltage-fluoroscopic tube current characteristic configured as a writable storage means for reading out the fluoroscopic tube current with the controlled tube voltage value as an address Means, a data memory for storing a fluoroscopic tube voltage-fluoroscopic current characteristic corresponding to each of various fluoroscopic modes, a fluoroscopic mode selecting means for selecting the fluoroscopic mode, and a fluoroscopic tube voltage according to the selected fluoroscopic mode- A CPU for reading a fluoroscopic tube current characteristic from the data memory and writing the same to the generating means.