JPH02312194A - Byplane type x-ray radiographing device - Google Patents

Abstract

PURPOSE:To miniaturize and lighten a high pressure transformer so as to obtain a small x-ray photographing device by converting an alternating voltage to a direct voltage by means of a rectifying circuit, and converting the direct voltage to a high frequency alternating voltage by means of an inverter, and boosting the high frequency alternating voltage to produce a high voltage, in a high voltage generating device. CONSTITUTION:A voltage to be applied to X-ray tubes 50a, 50b is generated by converting an alternating voltage to a direct voltage by means of a rectifying circuit 21, and converting the voltage to a high frequency alternating voltage by means of inverter circuits 300a, 300b (300) and applying the high frequency alternating voltage to the first side of high pressure transformers 40a, 40b(40) to produce a predetermined high voltage on the secondary side, and rectifying and smoothing the alternating high voltage; i.e., since the frequency of the voltage applied to the first side of the high pressure transformer 40 is made higher than a commercial power source frequency by the inverter circuit 300, the applied voltage time product is smaller than if a voltage of a normal commercial power source frequency is applied, and so the cross section of the transformer iron core can be small, which enables miniaturization and weight reduction of a high pressure transformer. Miniaturization of the x-ray photographing device is thus achieved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an X-ray imaging device, and particularly to a biplane X-ray imaging device that performs X-ray imaging of the same diagnostic region of a subject from two directions. It is.

[Conventional technology]

FIG. 4 shows a conventional system configuration of a biplane X-ray imaging device. In FIG. 4, 1 is a subject, 5a is an Xa tube for lateral imaging, 3a, 7a, and 6a are an X-ray high voltage generator for lateral imaging, an X-ray control unit, and an X#i
It is a photography unit, 5blt positive WNH Kage no X,
The S tubes 3b, 7b and 6b are also an X-ray high voltage generator for frontal photography, an X-ray control unit, and an X-ray photography unit. In addition, in the illustrated example, the system for frontal photography has X
An X-ray fluorescence intensifier unit (X-ray image intensifier, hereinafter referred to as 1.I) 6c for fluoroscopy and a monitor TV 6d are added, and these are used to position the imaging site and inject contrast medium. used for am.

As mentioned above, the conventional biplane type X-ray imaging device has an X-ray tube and an X-ray photography unit arranged separately in pairs in two directions, for example, the positive side, and also has a system that corresponds to these imaging systems. The configuration is such that an X-ray high voltage generator and an X-ray control unit are also provided for each system. After positioning the region to be imaged using fluoroscopy using an imaging system equipped with I, the two sets of imaging systems are operated alternately to perform imaging from two directions to obtain diagnostic information.

[Problem to be solved by the invention]

As described above, the conventional apparatus has the disadvantage that the apparatus becomes large because the two sets of imaging systems are each provided with an X-ray high voltage generator and an X-ray control apparatus. Biplane type
Since the purpose of radiography equipment is X-ray diagnosis of the circulatory system, it is necessary to be able to emit high-output, short-duration X-rays at high speed, so the X#I high-voltage generator has become larger. At the same time, it became necessary to provide a tetrode unit (high voltage control and switching control unit) on the secondary side of the X-ray high voltage generator, which led to further increase in size and cost.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the conventional apparatus described above, and more specifically, to provide a biplane type X-ray imaging apparatus that is small and inexpensive.

[Means to solve the problem]

In order to achieve the above object, the present invention replaces a high voltage generator in a conventional biplane X-ray imaging device with a rectifier circuit that converts an alternating current voltage into a direct current voltage, and a rectifier circuit that converts the output voltage of this rectifier circuit into a high frequency alternating current. It consists of an inverter circuit that boosts the output voltage of the inverter circuit, and a high-voltage transformer that boosts the output voltage of the inverter circuit.

It is characterized by a miniaturized high voltage generator.

The present invention further includes a single AC/DC conversion circuit that rectifies and smoothes the commercial power supply voltage and outputs the same, and outputs high-frequency alternating current by inputting the output voltage of this AC/DC conversion circuit, and emits X-rays. A pair of inverter circuits performs a stop switching operation, a pair of high voltage transformers are connected to each of these inverter circuits and step up the input voltage, and the output voltage of these high voltage transformers is rectified and smoothed before being applied. A pair of Xa arranged to intersect the center direction of the radiating xg
a pair of X-ray imaging units disposed opposite to the X-ray tube with the intersection of the centers of the emitted X-rays in between, and the pair of inverter circuits to The effect is even more pronounced by configuring a biplane X-ray imaging device that includes an X-ray control unit that emits X-rays from the ray tube, and even more effective if a resonant inverter is used as the inverter circuit. .

[Effect]

One of the reasons why conventional biplane X-ray equipment that does not use an inverter becomes larger and more expensive is the high voltage generator,
In particular, the high-voltage transformer is large, and a transformer and tetrode unit for controlling the voltage applied to the X-ray tube are required, and two sets of these are required. In item 1, the voltage applied to the X-ray tube is determined by first converting AC voltage into DC voltage using a rectifier circuit, then converting this voltage into high-frequency AC using an inverter circuit, and applying it to the primary side of a high-voltage transformer. A predetermined high voltage is generated on the next side, and this alternating current high voltage is rectified and smoothed. In other words, the frequency of the voltage applied to the primary side of the high-voltage transformer is set to a higher frequency than the commercial high power source frequency by the inverter circuit, so the applied voltage is higher than when the voltage at the conventional commercial power frequency is applied. Since the time product becomes smaller, the cross-sectional area of the transformer core does not need to be smaller, making it possible to make the high-voltage transformer smaller and lighter.

Therefore, the biplane 2X@ photographing device can be made smaller.

Moreover, in claim 2, the commercial power supply voltage is rectified.

The AC/DC conversion circuit and the pair of inverter circuits are connected so that the DC voltage from the single AC/DC conversion circuit that is smoothed and output can be supplied to the pair of inverter circuits. Power is supplied to the x-ray tube by an x-ray control unit switching the operation of a pair of inverter circuits. Therefore, when the X-ray control unit operates either of the pair of inverter circuits, or alternately, a single AC/
When a high-frequency AC voltage is applied to the primary side of a high-voltage transformer connected to it via an inverter circuit operated from a DC conversion circuit, a high voltage is induced on the secondary side, which is rectified and smoothed and applied to the X-ray tube. X-rays are emitted. In this operation, the inverter circuit performs the function of switching the X-ray emission in addition to simply increasing the frequency of the commercial power supply voltage.

Furthermore, in claim 3, since the inverter circuit is a resonant inverter, by controlling the frequency or phase difference of the inverter, the voltage supplied from the AC/DC conversion circuit can be arbitrarily controlled to convert the high voltage transformer into a high voltage transformer. can be output to the secondary side of

In other words, the tube voltage can be controlled arbitrarily.

〔Example〕

A preferred embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a block diagram of a biplane type X-ray imaging apparatus according to the present invention. In the figure, 10 is a commercial power source, which is shown as a three-phase AC power source in the figure. 20 is a first rectifier circuit (AC/DC conversion circuit) 30a that converts the AC voltage supplied from the commercial power supply 10 into DC voltage, smoothes it, and outputs it;
Reference numeral 30b denotes a high-voltage generator that converts the DC voltage supplied from the first rectifier circuit 20 into high-frequency AC, boosts it, rectifies it, and outputs the same, which will be described later.

It includes an inverter circuit, a high voltage transformer and a second rectifier circuit. Reference numerals 50a and 50b are X-ray generators that include an X-ray tube and a collimator. In the figure, 50a is for lateral imaging in which X-rays are emitted from the side to the subject 1, and 50b is for the front (front) to the subject 1. This is for frontal imaging, emitting X-rays from the back). 60a and 60b are X-rays for imprinting the X-ray image transmitted through the subject 1 onto the x1 image recording medium 1, for example, an X-ray film.
Among the line photography units, 60b is shown in a position retracted from the photography position in the figure. 65 is X-ray tube 5
67 is an X-ray fluorescence intensifier unit (X-ray image intensifier, hereinafter referred to as 1, I) that converts an X-ray image emitted from 0b and transmitted through the subject 1 into a visible light image.
An optical image of the secondary phosphor screen of I65 was captured using a photographing tube (not shown).
A monitor TV is provided for viewing a fluoroscopic image, positioning the area to be imaged, and observing the condition of the contrast medium injected into the subject 1. 70 is an X-ray control unit that controls the high pressure generating parts 30a and 30b to
An automatic brightness adjustment device is provided inside to control the brightness of the perspective image displayed on the monitor TV 67 to a constant level. With this automatic brightness adjustment device,
The fluoroscopic tube voltage and the fluoroscopic tube current are set according to the part of the subject 1 to be imaged. The X-ray control unit 7o also automatically controls the imaging tube voltage, imaging tube current, and imaging time (X-ray radiation time) according to the fluoroscopy tube voltage, fluoroscopy tube current, sensitivity of the X-ray film, etc. It also has an automatic exposure device that allows you to set the blackness of the film at a constant level.

Next, the operation of the apparatus having the configuration shown in FIG. 1 will be explained. First, 1. With I 65 facing the subject 1 as shown, the fluoroscopic method is selected, and the X-ray control unit 70 sends an operation signal to the inverter circuit of the high voltage generating section 30b connected to the X-ray tube 50b.

This operating signal is transmitted from the commercial power supply 10. It is set so that when the DC voltage supplied from the first rectifier circuit 20 is boosted by a high-voltage transformer, a voltage suitable for fluoroscopy is applied to the X-ray tube. Fluoroscopic X-rays are emitted from the X-ray tube 50b to the subject 1, the transmitted X-rays are converted into an optical image by the LI 65, and the fluoroscopic image is displayed on the monitor TV 67. 1. A part of the output signal of the secondary phosphor screen of I 65 is input to the automatic brightness adjustment device, and the X-ray control unit 70 adjusts this signal to a preset value so that the brightness of monitor TV 67 becomes a predetermined value.
The feedback is carried out and the viewing conditions are determined.

Next, while looking at the fluoroscopic image, the operator moves the table 2 and the imaging system to position the region to be imaged, and when the positioning is completed, the surgical technique is switched to imaging. I, I65
The positions of the xIX photography unit 60b and the xIX photography unit 60b are swapped, and photography 11! Preparations are complete. Here, a contrast agent is injected into the subject 1 using a contrast agent injector (not shown). At the timing when the contrast medium reaches the imaging site, the X-ray control unit 7o alternately sends imaging commands to the high pressure generators 30a and 30b.

This imaging command operates the inverter circuit so that the imaging conditions obtained from the fluoroscopic conditions are met. When one inverter circuit operates according to this command, the AC voltage supplied from the commercial power supply 10 is converted into a DC voltage by the first rectifier circuit 20, smoothed, and applied to the respective input terminals of the two inverter circuits. However, since the inverter circuit to which the command is not input is equivalent to an open switch, no voltage is output to its output terminal. The inverter circuit into which the operation command is input is configured to convert the input DC voltage into an AC voltage with a frequency higher than the commercial power supply frequency by alternately turning on and off a pair of switching elements, and converting the input DC voltage into a high-voltage transformer and a second rectifier. The voltage output through the circuit is converted into an alternating current voltage that becomes the camera tube voltage. The high-frequency AC voltage output from the inverter circuit is boosted by a high-voltage transformer, rectified by a second rectifier circuit, smoothed by the stray capacitance of the high-voltage cable, etc., and applied to the xi tube, where it is passed through the X-ray tube to the subject 11\ X-rays are emitted.

X-rays are alternately emitted from the X-ray tubes 50a and 50b,
The X-ray images are imprinted on the X-ray photography units GOa and 60b. The X-ray photographing units 60a and 60b are provided with X-ray detectors, and the output signals from the X-ray detectors are time-integrated by a first timer, and when the value reaches a predetermined value for each photographing, , the operation command from the X-ray control unit to the inverter circuit stops, and the radiation of xi stops.

In this embodiment, the voltage applied to the primary side of the high-voltage transformer of the high-voltage generator is made to have a higher frequency than the commercial power supply frequency by the inverter circuit.

High-voltage transformers are significantly smaller than conventional equipment.

This effect is particularly great in high-output biplane X-ray devices aimed at diagnosing the circulatory system.

Next, a second preferred embodiment of the present invention will be described with reference to FIG. In FIG. 2, the X-edge image receiving system in FIG. 1 is omitted, and the same components as in FIG. 1 are designated by the same reference numerals, so their explanation will be omitted.

21 is a three-phase full-wave rectifier circuit that rectifies the three-phase AC voltage input from the commercial power supply 10; 22 and 23 are smoothing glue handles and capacitors; It consists of

31a to 34a and 31b to 34b are transistors, and 35a to 38a and 35b to 38b are diodes connected in antiparallel to the transistors, and these transistors 31a to 34a and diodes 35a to 3
8a to form a full-bridge type first inverter 300a, and transistors 31b to 34b and a diode 35b.
38b constitute a second full-bridge inverter 300b. The input terminals of these inverters are commonly connected to both poles of the capacitor 23. 39a and 39b are high voltage transformers 40a and 40
Resonant capacitor connected in series to the primary winding of b, 41
a and 41b are rectifier circuits that rectify the output voltages of the high voltage transformers 40a and 40b, respectively; 42a and 42b are resistors that detect the voltage applied between the anodes and cathodes of the X-ray tubes 50a and 50b, that is, the tube voltage; 43a and 43b
compares the tube voltage detection value detected by the resistors 42a, 42b with the tube voltage setting value, and sends a signal (inverter operating frequency or operating phase difference) to control the inverters 300a, 300b so that the two match. The voltage controllers 44a and 44b that generate the control signals) are base drive circuits that amplify the output signals of the voltage controllers 43a and 43b and supply them to the bases of the transistors of each inverter.

70 is a signal Sta+Sxb for setting the fluoroscopy tube voltage and imaging tube voltage to the voltage controllers 43a and 43b.

It is also an X-ray control unit that outputs X-ray radiation signals Sza and S2b, and is configured to control both the first and second inverters 300a and 300b with a single unit. Note that since the present invention mainly relates to a high voltage generation circuit system, the tube current control system is omitted.

Next, the operation of this embodiment will be explained at the time of photographing.

In the same manner as in the embodiment shown in FIG. 1, when the front and side imaging conditions are set from the fluoroscopic conditions, the X-ray control unit 70 sends the imaging tube voltage and imaging time 1 imaging tube current (not shown).
The signals S1a and Stb for setting the voltage controllers 43a and 4
3b to generate a signal for operating inverters 300a and 300b. Here, when an imaging command (X-ray radiation command) is input to the X-ray control unit 70 by the operator's operation, the X-ray control unit 70 sends signals Sza and Szb that drive the front and side inverters to the voltage controller 43.
a.

43b separately and alternately. Note that the signals Sla and S
za, Stb and 82111 are voltage controller 4 at the same time.
It may also be output to 3a and 43b.

A three-phase full-wave rectifier circuit 2 converts the voltage supplied from a three-phase AC power source into a three-phase full-wave rectifier circuit 2.
The DC voltage that has been full-wave rectified by 1 and smoothed by the smoothing glue handle 22 and the capacitor 23 is sent to the inverters 300a and 3.
It is applied to the input terminal of 00b. X-ray radiation signal S2 is sent from the X-ray control unit 70 to the voltage controllers 43a and 43b.
a. When 5ell is input, the inverter starts operating. below.

The operation of inverter 300a will be explained.

When the X-ray radiation signal Sza is input to the voltage controller 43a,
The voltage controller 43a controls the transistor 31a of the inverter 300a, which is generated based on the imaging tube voltage setting signal Sza.
A control signal for driving .about.34a is output to the base drive circuit 44a. This control signal is the transistor 31a
and 348. The base drive circuit 44a is also a signal that performs a switching operation to turn on and turn off the transistors 32a and 33a as a pair, and controls their operating frequency or the operating phase difference between the transistors 31a and 34a and 32a and 33a. The signal is amplified and input to transistors 31a to 34a.

When the inverter 300a receives the control signal, it alternately turns on the transistors 31a and 34a, and 32a and 33a. First, when the transistors 31a and 34a are turned on as a pair, a current (resonant current) with a resonance period determined by the capacitor and inductance flows into the high voltage transformer 40a.

Of the capacitors and inductances that determine the resonance period,
The capacitor consists of a resonance capacitor 39a connected in series to the primary winding of the high voltage transformer 40a, a stray capacitance existing between the eyebrows of the secondary winding of the high voltage transformer 40a, and a stray capacitance of the high voltage cable (not shown). The inductance is the leakage inductance of the high voltage transformer 40a and the inductance of the wiring.

During the half period of the frequency period in which the transistors 31a and 34a are turned on, the resonant current first flows through the circuit of the transistor 31a -> the resonant capacitor 39a -> the primary winding of the high voltage transformer 40a -> the arc of the resonant frequency of the transistor 34a. flows, and for a certain time (1/2 of the resonance period)
), the resonant current becomes zero and now flows in the opposite direction in the circuit of diode 38a -> primary winding of high voltage transformer 40a -> resonant capacitor 39a -> diode 35a.

Then, the transistors 31a and 34a are turned off,
In the next half cycle, transistor 32a.

33a is turned on. Then, a resonant current flows in a circuit in which the transistors and diodes are replaced with those described above.

An alternating current obtained by subtracting the excitation current of the high voltage transformer 40a and the current flowing to the stray capacitance of the secondary winding from the primary current flowing through the primary winding of the high voltage transformer 40a is rectified by the rectifier 41a, and the floating capacitance of the high voltage cable is rectified. The X-ray tube 50a is smoothed by the capacitance
X-rays are emitted.

A signal corresponding to the actual tube voltage detected by the tube voltage detection resistor 42a is input to the voltage controller 43a, and the operating frequency or phase difference of the inverter is adjusted so that the difference between the set tube voltage signal and it becomes zero. A control signal is created, and this signal is applied to the bases of transistors 31a-34a via base drive circuit 44a. As a result, the operation of the inverter 300a in the next cycle is corrected, and the tube voltage is accurately controlled to the set value. The waveform value becomes V b 1 in FIG.

The X-ray radiation from the X-ray tube 50a is input to the voltage controller 43a (No. a SL! or Sza is turned off) when the signal of the phototimer of the automatic exposure mechanism explained in the example of FIG. This will stop the process.

Next, the inverter 300b operates in the same manner to
X-rays are emitted from 0b. The tube voltage waveform at this time becomes vk2 in FIG.

According to Example 5, the tube voltage can be arbitrarily varied by controlling the operating frequency or phase of the inverter in accordance with the set value, and the imaging time can also be arbitrarily varied by controlling the voltage controller. I can do it.

By increasing the inverter frequency, control can be performed for as short as 1 ms. Further, since a tube voltage feedback control mechanism is provided, the actual tube voltage can be accurately controlled with respect to the set value, and since this control is performed by switching transistors, responsiveness can be improved.

The gist of the present invention is for the front side of a biplane type X-ray imaging device;
A single DC power supply circuit generates DC voltage to apply to each side X-ray tube, and it is made positive.

After supplying it to the inverters on the two side systems and increasing the frequency, it is boosted by a high-voltage transformer to generate a positive voltage.

The point is that the side switching is performed by a switching operation of an inverter, and it is possible to modify the above embodiment without departing from the gist thereof.

For example, in the above embodiment, a resonant inverter is used as the inverter, but this is because the combination of a resonant inverter and a transformer allows variable control of the output voltage with the simplest configuration. If the tube voltage is controlled by another means 1, for example, a chopper circuit provided on the input side of the inverter, the inverter does not need to be of the resonant type. Furthermore, instead of the free bridge type inverter, a half bridge type or other type may be used, and the switching elements of the inverter may be thyristors instead of power transistors.

GTO, IGBT, etc. may also be used.

〔Effect of the invention〕

As described above, according to claim 1 of the present invention.

In biplane X-ray imaging equipment, the high voltage generator generates high voltage by converting AC voltage into DC using a rectifier circuit, converting it into high frequency AC using an inverter, and boosting the voltage using a high voltage transformer. The transformer can be made significantly smaller and lighter. This has great advantages for high-output devices intended for circulatory system diagnosis.

According to claim 2, in addition to the effects of claim 1, control of emitting and stopping X-rays in two directions is performed by controlling switching operations of two inverters using a single X-ray control unit. As a result, the tetrode tube unit in the conventional device is not required, further reducing the size and weight of the device, and thus reducing the price.

According to claim 3, since tube voltage control is possible by controlling the operating frequency or phase difference of the resonant inverter,
There is no need for an autotransformer or tetrode tube unit as in conventional devices, and the circuit configuration is simplified, making it possible to reduce size, weight, and cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the main parts of a biplane type XL imaging device according to an embodiment of the present invention. Fig. 2 is a circuit diagram of the main part of another embodiment of the present invention, Fig. 3 is a diagram showing the relationship between the X-ray radiation signal of Figs. FIG. 4 is a block diagram showing the configuration of a conventional device. To the door... Commercial power supply, 20... Rectifier circuit, 30 a
e 30 b...high pressure generation part, 31 a to 34 a
, 3lb~34b...transistor, 35
a~38 a, 35 b~38b...diode, 39a, 39b...resonant capacitor, 40a, 4
0b-high voltage transformer, 43a, 43b... voltage controller,
44a, 44b...Base drive circuit, 70...
XIIA control unit, 200...DC power No. 1
3rd quickest 4th mouth

Claims (1)

[Claims] 1. A pair of imaging systems each consisting of an X-ray tube and an imaging device are arranged in two directions, each having a space into which a subject is inserted, and a commercial power supply voltage is applied to each of the X-ray tubes. In a biplane type X-ray imaging apparatus, each of the X-rays is The high voltage generator that supplies high voltage to the wire tube consists of a rectifier circuit that converts AC voltage to DC voltage, an inverter circuit that converts the output voltage of this rectifier circuit to high frequency AC, and a step-up of the output voltage of this inverter circuit. A biplane X-ray imaging device characterized by being equipped with a high-voltage transformer. 2. An AC/DC conversion circuit that receives commercial power supply voltage, rectifies it, smoothes it, and outputs it, and inputs the output voltage of this AC/DC conversion circuit and outputs high-frequency alternating current, as well as emitting and stopping X-rays. A pair of inverter circuits that perform switching operations, a pair of high-voltage transformers that are connected to each of these inverter circuits and boost the input voltage, and the output voltages of these high-voltage transformers are rectified, smoothed, applied, and radiated. a pair of X-ray tubes arranged to cross the X-ray center direction;
Each of the X
a pair of X-ray imaging units placed opposite to the ray tube;
and an X-ray control unit that controls the pair of inverter circuits to alternately emit X-rays from the pair of X-ray tubes. 3. The biplane X-ray imaging apparatus according to claim 1 or 2, characterized in that a resonant inverter is used as the inverter circuit.