JP6139262B2 - X-ray high voltage device - Google Patents

Description

  Embodiments described herein relate generally to an X-ray high voltage apparatus that supplies voltage to a multifocal X-ray tube.

  Conventionally, there is a method of controlling X-ray irradiation using a triode X-ray tube. The triode X-ray tube includes, for example, a rotating anode, a filament as a cathode, and a grid as a focusing electrode. By switching the potential of the grid (grid bias) with respect to the filament between a potential at which electrons can be emitted and a potential at which electrons cannot be emitted, the X-ray waveform can be changed in a pulse shape.

  The power supply for the grid bias is supplied using a high-voltage insulating transformer. For example, in a neutral point grounding X-ray high voltage apparatus, when the tube voltage of the X-ray tube is set to 150 kV, the insulation transformer needs a withstand voltage of 75 kV.

  In the triode X-ray tube, in addition to an insulating transformer for grid bias, an insulating transformer for power source for generating a tube voltage and an insulating transformer for power source for heating the filament are required. Furthermore, in a multifocal X-ray tube having a plurality of filaments, an insulating transformer for power supply for heating each filament is required by the number of each filament.

  It is necessary to secure a sufficient insulation distance for a high voltage insulation transformer. Therefore, when a large number of insulating transformers are required, the X-ray high voltage apparatus for supplying a voltage to the X-ray tube becomes large.

JP 2002-33064 A

  The purpose of the embodiment is to reduce the size of the X-ray high voltage apparatus.

  An X-ray high voltage apparatus according to an embodiment provides a high voltage to a multifocal X-ray tube including an anode, a plurality of filaments, and a grid that blocks electrons emitted from the plurality of filaments toward the anode. An X-ray high voltage apparatus to be supplied, comprising a plurality of inverters, a plurality of transformers, a plurality of rectifiers, and a switching circuit.

  The plurality of inverters are provided for each of the plurality of filaments. The plurality of transformers are connected to each of the plurality of inverters, transform the output from the inverter, and supply the transformed output to the filament corresponding to the connected inverter. The plurality of rectifiers rectify outputs transformed by at least two of the plurality of transformers to generate an output for grid bias. The switching circuit selectively switches the output supplied to the grid among the outputs rectified by the plurality of rectifiers.

1 is a block configuration diagram of an X-ray fluoroscopic apparatus according to an embodiment. The figure which shows the structure of the X-ray high voltage apparatus and X-ray tube in the embodiment. The time chart for demonstrating operation | movement of the X-ray high voltage apparatus in the embodiment. The time chart for demonstrating operation | movement of the X-ray high voltage apparatus in the embodiment. The time chart for demonstrating operation | movement of the X-ray high voltage apparatus in the embodiment. The time chart for demonstrating operation | movement of the X-ray high voltage apparatus in the embodiment.

An embodiment will be described with reference to the drawings.
In this embodiment, an X-ray fluoroscopic apparatus and an X-ray high voltage apparatus mounted on the apparatus are disclosed.

FIG. 1 is a block configuration diagram of an X-ray fluoroscopic apparatus 1 according to the present embodiment.
As shown in this figure, the X-ray fluoroscopic apparatus 1 includes an X-ray high voltage device 2, an X-ray tube 3, an X-ray diaphragm device 4, a top plate 5, a C arm 6, an X-ray detector 7, and an arm drive mechanism. 8, a top movement mechanism 9, a system control unit 10, an input unit 11, a display unit 12, a data conversion unit 13, a data storage unit 14, an image processing unit 15, and the like.

  The X-ray high voltage device 2 generates a high voltage to be supplied to the X-ray tube 3. The X-ray tube 3 generates X-rays based on the high voltage supplied from the X-ray high voltage device 2. The X-ray diaphragm device 4 narrows the X-rays emitted from the X-ray tube 3 so as to selectively irradiate the region of interest of the subject P. For example, the X-ray diaphragm device 4 has four slidable diaphragm blades, and narrows the X-rays by sliding these diaphragm blades. The X-ray tube 3 and the X-ray diaphragm device 4 constitute an X-ray source device 30.

  A subject P is placed on the top 5. The X-ray detector 7 includes a plurality of X-ray detection elements that detect X-rays transmitted through the subject P. Each of these X-ray detection elements converts the X-rays emitted from the X-ray tube 3 and transmitted through the subject P into electrical signals and accumulates them.

  The C-arm 6 is configured so that the X-ray source device 30 and the X-ray detector 7 face each other with the X-ray irradiation surface of the X-ray tube 3 and the X-ray detection surface of the X-ray detector 7 facing each other with the subject P interposed therebetween. Hold on. Instead of the C arm, another type of arm, for example, an Ω arm may be used.

  The arm drive mechanism 8 is a device for rotating and moving the C-arm 6. The top plate moving mechanism 9 moves the top plate 5 in a horizontal direction parallel to the placement surface and in a vertical direction perpendicular to the placement surface.

  The data conversion unit 13 reads out the electric charges accumulated in the X-ray detector 7 in synchronization with the X-ray pulse irradiation, converts the read electric signal into digital data, and outputs the digital data to the data storage unit 14. At this time, the data storage unit 14 stores the digital data output from the data conversion unit 13 as projection data.

  The image processing unit 15 performs various image processing such as window conversion and RGB processing on the projection data stored in the data storage unit 14 and outputs the projection data to the display unit 12 as an X-ray transmission image.

  The input unit 11 includes a mouse, a keyboard, a button, a trackball, a joystick, a foot switch, and the like used by an operator such as a doctor or engineer who operates the fluoroscopic imaging apparatus 1 to input various commands and information. The command and information input by the device are output to the system control unit 10. The input unit 11 in the present embodiment includes a fluoroscopic switch SWF and a photographing switch SWS. The fluoroscopic switch SWF is a switch for the operator to input a command for continuously observing the subject P. There are cases where fluoroscopy is generated continuously or in the form of pulses. The imaging switch SWS is a switch for an operator to input a command for imaging the subject P with X-rays having energy higher than that of the pulse X-ray.

  The display unit 12 includes a monitor which is, for example, an LCD (Liquid Crystal Display), and is input from a GUI (Graphical User Interface) for receiving an input from an operator or the image processing unit 15 via the input unit 11. An X-ray transmission image is displayed.

  The system control unit 10 includes a processor and a memory, and controls the operation of the entire X-ray fluoroscopic apparatus 1. That is, the system control unit 10 controls the X-ray high-voltage device 2, the arm drive mechanism 8, the X-ray diaphragm device 4, and the like based on commands from the operator input via the input unit 11. Thus, adjustment of the X-ray dose irradiated to the subject P, ON / OFF control of X-ray irradiation, rotation / movement control of the C arm 6, movement control of the top 5 and the like are performed. Further, the system control unit 10 controls the image processing unit 15 based on a command or the like input from the operator via the input unit 11. Furthermore, the system control unit 10 performs control for causing the display unit 12 to display the GUI and the like.

  Detailed configurations of the X-ray high voltage apparatus 2 and the X-ray tube 3 will be described with reference to FIG.

  The X-ray tube 3 is a multifocal X-ray tube that employs a grid control system. The X-ray tube 3 includes an anode 31, a first filament 321 for a large focal point, a second filament 322 for a small focal point, and a grid 33. The first filament 321 and the second filament 322 are cathodes.

  The X-ray high voltage apparatus 2 includes a high voltage inverter 201, a high voltage transformer 202, and a high voltage rectifier 203 as a circuit for applying a tube voltage to the X-ray tube 3. The high-voltage inverter 201 switches a direct current supplied from a commercial AC power source via a rectifier (not shown) to generate an alternating current with a predetermined frequency. The high voltage transformer 202 is an insulating transformer including a primary winding 202 a connected to the high voltage inverter 201 and a secondary winding 202 b connected to the high voltage rectifier 203. When alternating current is supplied from the high voltage inverter 201 to the primary winding 202a, the boosted alternating current is output from the secondary winding 202b to the high voltage rectifier 203. The high voltage rectifier 203 converts alternating current input from the high voltage transformer 202 into direct current, and applies it between the anode 31 of the X-ray tube 3 and the first filament 321 or the second filament 322.

  The X-ray high voltage apparatus 2 includes a first inverter 211 and a first transformer 212 as a circuit for heating the first filament 321, and as a circuit for heating the second filament 322, A second inverter 221 and a second transformer 222 are provided. The first inverter 211 and the second inverter 221 switch direct current supplied from a commercial alternating-current power supply via a rectifier (not shown) to generate alternating current with a predetermined frequency. The first transformer 212 is an insulating transformer including a primary winding 212 a connected to the first inverter 211 and a secondary winding 212 b connected to the first filament 321. The second transformer 222 is an insulating transformer including a primary winding 222 a connected to the second inverter 221 and a secondary winding 222 b connected to the second filament 322. When alternating current is supplied from the first inverter 211 to the primary winding 212a, the transformed alternating current is output from the secondary winding 212b. Based on the output from the secondary winding 212b, the first filament 321 is heated. When alternating current is supplied from the second inverter 221 to the primary winding 222a, the transformed alternating current is output from the secondary winding 222b. Based on the output from the secondary winding 222b, the second filament 322 is heated.

  The X-ray high voltage apparatus 2 includes secondary windings 212 c and 222 c, a first rectifier 213, a second rectifier 223, and a switching circuit 230 as circuits for applying a grid bias to the X-ray tube 3. , Switch SW0, two resistors R, and a capacitor C. The secondary winding 212 c is wound around the core of the first transformer 212. The secondary winding 222 c is wound around the core of the second transformer 222. The switching circuit 230 includes a switch SW1 that opens and closes a connection line that connects the first rectifier 213 and the grid 33, and a switch SW2 that opens and closes a connection line that connects the second rectifier 223 and the grid 33. When alternating current is supplied from the first inverter 211 to the primary winding 212a, alternating current transformed from the secondary winding 212c to the first rectifier 213 is output. The first rectifier 213 converts the alternating current input from the first transformer 212 into direct current, and applies the converted direct current to the grid 33 as a grid bias. The second rectifier 223 converts the alternating current input from the second transformer 222 into direct current, and applies the converted direct current to the grid 33 as a grid bias.

  Further, the X-ray high voltage apparatus 2 includes a control circuit 240. The control circuit 240 supplies a drive pulse signal to each of the inverters 201, 211, and 221. Each inverter 201, 211, 221 outputs an alternating current according to the duty (pulse generation interval / pulse period) of this drive pulse signal, for example. The control circuit 240 opens / closes (turns on / off) the switch SW0 to turn on / off the application of the grid bias. In addition, the control circuit 240 switches the power source used for applying the grid bias between the first inverter 211 and the second inverter 221 by opening and closing (ON / OFF) the switches SW0, SW1, and SW2.

  When irradiating the subject P with X-rays, the two focal points are not used simultaneously. Therefore, in the present embodiment, power for preheating and grid bias is supplied to a transformer that is not used for X-ray irradiation, among the first transformer 212 and the second transformer 222. In addition, preheating is heating the said filament in order to raise the temperature of a filament to predetermined temperature beforehand as a preparatory step for generating an X-ray. The preheating is performed with a heating amount such that almost no tube current flows through the X-ray tube 3 even when a high voltage is applied to the X-ray tube 3. The focus used for fluoroscopy and shooting can be arbitrarily switched by the operator by operating the input unit 11.

A specific operation of the X-ray high voltage apparatus 2 will be described.
3 to 6 all show temporal changes of the fluoroscopic switch SWF, the imaging switch SWS, the switch SW0, the switch SW1, the switch SW2, the first focal tube current I1, the second focal tube current I2, and the grid bias Vg. It is a time chart. The first focal tube current I1 is a tube current when X-rays are generated by the first filament 321, and the second focal tube current I2 is a tube when X-rays are generated by the second filament 322. Current.

  In the time chart of FIG. 3, the subject P is seen through with X-rays generated in pulses by the first filament 321, and the subject P is displayed with single X-rays generated by the first filament 321. This corresponds to shooting.

  At the beginning of the time chart, the switches SWF, SWS, SW0, SW1, and SW2 are all turned off. When the operator turns on the fluoroscopic switch SWF, the system control unit 10 instructs the X-ray high voltage apparatus 2 to start fluoroscopy. In response to receiving this command, the control circuit 240 turns on the switch SW2. Further, the control circuit 240 starts fluoroscopic drive control of each of the inverters 201, 211, and 221. Thereafter, when the operator turns off the fluoroscopic switch SWF, the system control unit 10 instructs the X-ray high voltage apparatus 2 to end fluoroscopy. In response to receiving this command, control circuit 240 turns off switch SW2. Further, the control circuit 240 shifts the drive control of each of the inverters 201, 211, and 221 from the fluoroscopic state to the standby state (a state in which all filaments are preheated).

  While the switch SW2 is on, the grid bias Vg at a potential (for example, −3 kV) at which electrons cannot be emitted from the first filament 321 toward the anode 31 using the output from the second transformer 222 as a power source is X Applied to the tube 3. At this time, electrons emitted from the first filament 321 are blocked by the grid 33.

  The control circuit 240 turns on the switch SW0 at a predetermined cycle while the switch SW2 is turned on. While the switch SW0 is on, the grid 33 and the first filament 321 are short-circuited, so the grid bias Vg becomes zero. Therefore, the first focal tube current I1 using the first filament 321 rises to 50 mA, for example. In this way, pulsed X-rays corresponding to the tube current I1 that periodically rises are irradiated from the X-ray tube 3 to the subject P.

  When the operator turns on the imaging switch SWS, the system control unit 10 instructs the X-ray high voltage apparatus 2 to start imaging. Upon receiving this command, the control circuit 240 waits for the elapse of a predetermined imaging preparation period T, drives the high voltage inverter 201 and the first inverter 211, and supplies the X-ray tube 3 to the first 200 mA, for example. An X-ray for imaging is generated by supplying a focal tube current I1. During such shooting, the switches SW0, SW1, and SW2 are all kept off.

  Regardless of the state of the switches SWF and SWS, the second inverter 221 outputs a low-level alternating current set for preheating and preheats the second filament 322.

  In the time chart of FIG. 4, the subject P is seen through with X-rays generated in pulses by the second filament 322, and the subject P is detected with single X-rays generated by the second filament 322. This corresponds to shooting.

  At the beginning of the time chart, the switches SWF, SWS, SW0, SW1, and SW2 are all turned off. When the operator turns on the fluoroscopic switch SWF, the system control unit 10 instructs the X-ray high voltage apparatus 2 to start fluoroscopy. In response to receiving this command, the control circuit 240 turns on the switch SW1. Further, the control circuit 240 starts fluoroscopic drive control of each of the inverters 201, 211, and 221. Thereafter, when the operator turns off the fluoroscopic switch SWF, the system control unit 10 instructs the X-ray high voltage apparatus 2 to end fluoroscopy. In response to receiving this command, the control circuit 240 turns off the switch SW1. Further, the control circuit 240 shifts the drive control of each of the inverters 201, 211, and 221 from the fluoroscopic state to the standby state (a state in which all filaments are preheated).

  While the switch SW1 is on, the grid bias Vg at a potential (for example, −3 kV) at which electrons cannot be emitted from the second filament 322 toward the anode 31 using the output from the first transformer 212 as a power source is X Applied to the tube 3. At this time, electrons emitted from the second filament 322 are blocked by the grid 33.

  The control circuit 240 turns on the switch SW0 at a predetermined cycle while the switch SW1 is on. While the switch SW0 is turned on, the grid 33 and the second filament 322 are short-circuited, so the grid bias Vg becomes zero. Therefore, the second focal tube current I2 using the second filament 322 rises to 50 mA, for example. In this way, a pulsed X-ray corresponding to the tube current I2 that periodically rises is irradiated from the X-ray tube 3 to the subject P.

  When the operator turns on the imaging switch SWS, the system control unit 10 instructs the X-ray high voltage apparatus 2 to start imaging. When receiving this command, the control circuit 240 waits for the elapse of a predetermined imaging preparation period T, drives the high voltage inverter 201 and the second inverter 221, and supplies the X-ray tube 3 with a second current of 200 mA, for example. A focus tube current I2 is supplied to generate X-rays for imaging. During such shooting, the switches SW0, SW1, and SW2 are all kept off.

  Regardless of the state of the switches SWF and SWS, the first inverter 211 outputs a low-level alternating current set for preheating, and preheats the first filament 321.

  In the time chart of FIG. 5, the subject P is seen through with X-rays generated in pulses by the first filament 321, and the subject P is detected with single X-rays generated by the second filament 322. This corresponds to shooting.

  In this case, the operation of the control circuit 240 at the time of fluoroscopy is the same as that of FIG. 3, and the operation of the control circuit 240 at the time of photographing is the same as that of FIG.

  In the time chart of FIG. 6, the subject P is seen through with X-rays generated in pulses by the second filament 322, and the subject P is detected with single X-rays generated by the first filament 321. This corresponds to shooting.

  In this case, the operation of the control circuit 240 at the time of fluoroscopy is the same as that of FIG. 4, and the operation of the control circuit 240 at the time of photographing is the same as that of FIG.

The effect of this embodiment will be described.
A conventional X-ray high voltage apparatus includes an inverter and a transformer for grid bias and an inverter and a transformer for heating each filament. On the other hand, the X-ray high voltage apparatus 2 according to the present embodiment is configured to share the inverter and transformer for heating the first filament 321 and the second filament 322 and the inverter and transformer for grid bias. It is. Therefore, the number of inverters and transformers can be reduced.

  It is necessary to secure a sufficient insulation distance for a high voltage insulation transformer. Therefore, by reducing the number of inverters and transformers, the X-ray high voltage apparatus 2 or the X-ray fluoroscopic apparatus 1 can be reduced in size.

Thus, if the X-ray high voltage apparatus 2 or the X-ray fluoroscopic apparatus 1 is downsized, a doctor or the like can use the space around the X-ray fluoroscopic apparatus 1 widely. Therefore, for example, when performing a procedure while seeing through the subject P with the X-ray fluoroscopic imaging apparatus 1, it is difficult for the apparatus to hinder the operation of a doctor or the like, so that the doctor or the like can proceed with the procedure smoothly.
In addition to these, various suitable effects can be obtained from the configuration disclosed in the present embodiment.

(Modification)
Several modifications will be described.

  In the present embodiment, the X-ray fluoroscopic apparatus 1 and the X-ray high voltage apparatus 2 mounted on the apparatus are exemplified. However, the configuration of the X-ray high voltage apparatus shown in FIG. 2 can also be applied to an X-ray high voltage apparatus provided in another type of apparatus such as an X-ray computed tomography apparatus.

  In this embodiment, the X-ray high voltage apparatus 2 which applies a tube voltage etc. to the X-ray tube 3 provided with two filaments was illustrated. However, a configuration similar to that of the X-ray high voltage apparatus 2 can be applied to an X-ray high voltage apparatus that applies a tube voltage or the like to an X-ray tube having a larger number of filaments. For example, when the X-ray tube includes n (an integer of 3 or more) filaments, the X-ray high-voltage device includes n inverters for heating each filament and n transformers. In this X-ray high voltage apparatus, a secondary winding for grid bias is provided in at least two cores of n transformers, a rectifier is connected to each secondary winding, and each rectifier and the grid 33 are connected. A switch similar to the switches SW1 and SW2 is provided in the connecting line. The control circuit of the X-ray high-voltage device selectively switches these switches so that an inverter and a transformer for heating filaments not used for X-ray irradiation are used as a grid bias power source. Even in this case, the number of inverters and transformers to be mounted on the X-ray high voltage apparatus can be reduced, and the apparatus can be downsized.

  Although several embodiments of the present invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... X-ray fluoroscopic apparatus, 2 ... X-ray high voltage apparatus, 3 ... X-ray tube, 321 ... 1st filament, 322 ... 2nd filament, 33 ... Grid, SW0, SW1, SW2 ... Switch, 211 ... 1st inverter 212 ... 1st transformer, 213 ... 1st rectifier, 221 ... 2nd inverter, 222 ... 2nd transformer, 223 ... 2nd rectifier, 230 ... switching circuit, 240 ... control circuit.

Claims (3)

An X-ray high voltage apparatus for supplying a high voltage to a multifocal X-ray tube comprising an anode, a plurality of filaments, and a grid that blocks electrons emitted from the plurality of filaments toward the anode,
A plurality of inverters provided for each of the plurality of filaments;
A plurality of transformers connected to each of the plurality of inverters, transforming the output from the inverter, and supplying the transformed output to the filament corresponding to the connected inverter,
A plurality of rectifiers that rectify outputs transformed by at least two of the plurality of transformers to generate an output for grid bias;
A switching circuit that selectively switches an output supplied to the grid between outputs rectified by the plurality of rectifiers;
An X-ray high voltage apparatus comprising: The switching circuit is a plurality of switches provided on each of a plurality of connection lines connecting each of the plurality of rectifiers to the grid .
The X-ray high voltage apparatus according to claim 1. In a series of X-ray irradiation using the multifocal X-ray tube, the rectifier connected to the transformer for supplying output to any one of the filaments not used for the X-ray irradiation is generated. A control circuit for operating the switching circuit so that the output is supplied to the grid,
The X-ray high voltage apparatus according to claim 1, further comprising:

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