WO2010026914A1 - X-ray ct device - Google Patents

X-ray ct device Download PDF

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Publication number
WO2010026914A1
WO2010026914A1 PCT/JP2009/064959 JP2009064959W WO2010026914A1 WO 2010026914 A1 WO2010026914 A1 WO 2010026914A1 JP 2009064959 W JP2009064959 W JP 2009064959W WO 2010026914 A1 WO2010026914 A1 WO 2010026914A1
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WO
WIPO (PCT)
Prior art keywords
tube voltage
ray
signal
tube
scanner
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Application number
PCT/JP2009/064959
Other languages
French (fr)
Japanese (ja)
Inventor
美奈 小川
拓也 堂本
貴之 正木
Original Assignee
株式会社 日立メディコ
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Application filed by 株式会社 日立メディコ filed Critical 株式会社 日立メディコ
Priority to JP2010527766A priority Critical patent/JP5314692B2/en
Publication of WO2010026914A1 publication Critical patent/WO2010026914A1/en

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/56—Details of data transmission or power supply, e.g. use of slip rings
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computerised tomographs
    • A61B6/032—Transmission computed tomography [CT]

Definitions

  • the present invention relates to an X-ray CT apparatus, and more particularly to a technique suitable for an X-ray CT apparatus capable of high-speed scanning.
  • the X-ray CT apparatus irradiates the subject with a fan-shaped, conical or pyramidal X-ray beam from various projection angles from the X-ray tube, and the X-ray transmitted through the subject is opposed to the X-ray tube.
  • the detected X-ray detector is used for detection, and the detected data is subjected to reconstruction calculation to obtain a tomographic image of the subject.
  • a helical scan method called helical scan or spiral scan is used.
  • the X-ray tube and X-ray detector are rotated while rotating the scanner rotating part while radiating X-rays from the X-ray tube, and the table on which the subject is placed is moved in the body axis direction.
  • the subject is scanned in a spiral shape.
  • power transmission means for continuously transmitting power to the X-ray tube mounted on the scanner rotation unit, and control signals and X-ray detection of the system controller that controls the entire CT system
  • signal transmission means for exchanging signals such as data detected by the scanner between the scanner stationary part and the scanner rotation part
  • power transmission means and signal transmission means comprising a slip ring and a brush are used.
  • Patent Document 1 discloses what transmits power to the side.
  • a signal transmission means using optical coupling combining a light emitting element and a light receiving element is used as a means for transmitting signals and X-ray detection data in a non-contact manner between the scanner stationary part and the scanner rotating part. It is disclosed in Patent Document 2 and Patent Document 3.
  • Patent Documents 1 to 3 only disclose the power transmission means and the signal transmission means between the scanner stationary part and the scanner rotating part. Therefore, in order to realize an X-ray CT system that eliminates the need for maintenance and inspection work of slip rings and brushes required by conventional devices by transmitting power and signals in a non-contact manner between the scanner stationary part and the scanner rotating part. Needs further ingenuity.
  • the inverter circuit Since the operation cycle is 50 ⁇ s, feedback control is performed with a delay of one cycle, making it difficult to stably control the tube voltage.
  • the operating frequency of the inverter circuit is set to be higher than 20 kHz. You can lower it, but doing so will increase the ripple of the tube voltage. Therefore, the image quality of the CT image is degraded.
  • the present invention has been made in view of the above-described problem, and is an X-ray in which transmission of power supplied to an X-ray tube and transmission of signals to be exchanged between a stationary part of a scanner and a scanner rotation part are made contactless.
  • the purpose is to provide a CT device.
  • the present invention provides a scanner stationary unit, a scanner rotating unit, a DC power source, an inverter circuit that converts DC power of the DC power source into high-frequency AC power, and output power of the inverter circuit as described above.
  • Non-contact power transmission means by electromagnetic induction for non-contact power transmission to the scanner rotation unit, a high voltage generator for boosting and rectifying the output voltage of the non-contact power transmission means to generate a tube voltage, and applying the tube voltage X-ray tube for generating X-rays irradiated to the subject, an X-ray detector for detecting a transmitted X-ray dose transmitted through the subject, a tube voltage control device for controlling the tube voltage, and the X-ray Scanner rotation means for rotating the scanner rotation unit around the subject with the tube and the X-ray detector facing each other, and reconstructing a tomographic image of the subject from data detected by the X-ray detector Image processing device And a system controller that controls each device and each means based on a set scan condition, and relates to control of tube voltage and / or tube current for generating X-rays A control signal, an anode drive control signal for controlling the rotation of the anode of the X-ray tube, and the X-ray detection data detected by the
  • the non-contact signal transmission means is preferably an optical coupling in which the electrical / optical signal conversion element and the optical / electrical signal conversion element are opposed to each other.
  • tube voltage control signal output from the tube voltage control device to the inverter circuit X-ray exposure output (start of tube voltage control) output from the system controller to the tube voltage control device, X-ray detector It is desirable to provide dedicated non-contact signal transmission means for transmitting the X-ray detection data of the subject detected by the above to the image processing apparatus.
  • the transmission of power supplied from the power source to the X-ray tube and the signal transmission between the scanner stationary part and the scanner rotating part are made non-contact.
  • the maintenance work of the slip ring like the X-ray CT apparatus becomes unnecessary.
  • the present invention provides an X-ray CT apparatus configured as described above, a tube voltage presetting means for applying a tube voltage not contributing to X-ray generation to the X-ray tube, and a state in which the tube voltage is preset. It is characterized by comprising tube voltage control starting means for starting tube voltage control.
  • the tube voltage preset means and the tube voltage control start means include tube voltage switching means provided in the stationary part of the scanner, and the tube voltage preset means responds to the X-ray exposure start signal by the tube voltage switching means.
  • a voltage preset signal is output as a drive signal for the inverter circuit, and the tube voltage control starting means sets the tube voltage from the tube voltage control device in place of the tube voltage preset signal when the tube voltage detection value reaches the preset value. It is desirable to be configured to output the signal as a drive signal for the inverter circuit.
  • the X-ray CT apparatus configured in this way can reduce the time delay of the X-ray exposure timing because the X-ray tube voltage is controlled from the preset value that does not contribute to X-ray generation to the set tube voltage.
  • the transmission of power supplied to the X-ray tube and the signal transmission exchanged between the scanner stationary unit and the scanner rotating unit are made non-contact and a tube voltage that does not contribute to the generation of X-rays is applied. Since the tube voltage feedback control is started from the above, the time delay of the tube voltage control applied to the X-ray tube is shortened, and high-speed scanning becomes possible. In addition, the maintenance time for the power transmission means and the signal transmission means is shortened and the reliability is improved.
  • FIG. 1 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to a first embodiment of the present invention.
  • the circuit diagram which shows schematic structure of an inverter circuit.
  • FIG. 2 is a block diagram showing a functional configuration of a tube voltage control unit of the X-ray CT apparatus shown in FIG. 3 is a flowchart for explaining the operation of the X-ray CT apparatus according to the first embodiment of the present invention.
  • FIG. 3 is a flowchart for explaining the operation of tube voltage control in the first embodiment of the present invention.
  • 3 is a timing chart for explaining the operation of tube voltage control in the first embodiment of the present invention.
  • the block diagram which shows schematic structure of the X-ray CT apparatus of the 2nd Embodiment of this invention.
  • the block diagram which shows the function structure of the tube voltage control part of the X-ray CT apparatus shown in FIG. 9 is a timing chart for explaining the operation of tube voltage control in the second embodiment of the present invention.
  • FIG. 5 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to a third embodiment of the present invention.
  • FIG. 13 is a block diagram showing a functional configuration of a tube voltage control unit of the X-ray CT apparatus shown in FIG. The figure which shows the whole structure of the X-ray CT apparatus of the 4th Embodiment of this invention.
  • FIG. 1 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to the first embodiment of the present invention.
  • the X-ray CT apparatus according to the first embodiment of the present invention includes a scanner stationary unit 1 and a scanner rotating unit 2 as shown in FIG.
  • the scanner stationary unit 1 is a power converter 11 that converts AC power supplied from a commercial power source 10 into AC power having a frequency higher than the frequency of the commercial power source 10, and an operation console 12 that is used to operate the CT system.
  • a CT image is generated by using the system controller 13 for controlling the entire system based on the scanning conditions set by the operation console 12 and the X-ray transmission data of the subject detected by an X-ray detector described later.
  • An image processing device 14 having an image reconstruction means, a display device 15 for displaying CT images and various information, a gantry (not shown) that rotatably supports the scanner rotation unit 2, and a rotation of the scanner rotation unit 2 And a scanner rotation driving unit (not shown) for driving.
  • an AND circuit 16 is provided between the power converter 11 and the system controller.
  • the scanner rotating unit 2 includes a high voltage generator 30 that boosts the AC voltage output from the power converter 11 of the scanner stationary unit 1 and converts the boosted voltage into a DC voltage, and the DC voltage output from the high voltage generator 30.
  • An X-ray tube 31 that emits X-rays when a high voltage is applied, a tube voltage detector 32 that detects a voltage (tube voltage) applied between the anode 31a and the cathode 31b of the X-ray tube 31, and a tube voltage
  • a tube voltage control device 33 for controlling the tube current detector 34 for detecting a current (tube current) flowing in the filament of the cathode 31b of the X-ray tube 31, a tube current control device 35 for controlling the tube current, From the anode rotation driving device 36 for controlling the rotation of the anode of the X-ray tube 31, the X-ray detection unit 39 disposed opposite to the X-ray tube 31 with the subject P interposed therebetween,
  • a collimator (not shown) that can variably set the radiation
  • a non-contact power transmission means 20 and a non-contact signal transmission means 40 are arranged.
  • the power converter 11 includes a converter circuit 11a that converts AC power supplied from the commercial power supply 10 into DC power, and an inverter circuit 11b that converts this DC power into AC power having a frequency higher than the frequency of the commercial power supply 10.
  • the inverter circuit 11b includes a plurality of power conversion semiconductor switching elements, for example, an inverter drive circuit 11c for switching and driving IGBTs (Insulated Gate Bipolar Transistors).
  • Fig. 2 shows the configuration of the inverter circuit 11b.
  • the inverter circuit 11b is configured as a full-wave bridge circuit by four power semiconductor switching elements IGBT1 to IGBT4.
  • this full-wave bridge circuit operates at a predetermined inverter operating frequency (1 / 2T1), for example, 20 kHz, and as shown in FIGS. 3 (b) to (e) In the positive half cycle of the operating frequency, the conduction width T2 of the switching elements IGBT1 and IGBT4 is controlled, and in the negative half cycle of the inverter operating frequency, the conduction width T2 of the switching elements IGBT2 and IGBT3 is controlled. As a result, the DC voltage supplied from the converter circuit 11a is converted into an arbitrary high-frequency AC voltage and output from the inverter circuit 11b to the non-contact power transmission means 20.
  • the conduction width T2 of the switching elements IGBT1 and IGBT4 and the conduction width T2 of the switching elements IGBT2 and IGBT3 are set to be the same.
  • FIG. 4 shows the relationship between the conduction ratio T2 / T1 of the switching elements IGBT1 to IGBT4 and the output voltage (effective value) of the inverter circuit 11b.
  • the output voltage of the inverter circuit 11b can be controlled from 0 to the maximum Emax by changing the conduction ratio T2 / T1 from 0 to 1, but in this embodiment, the inverter circuit 11b The operation is started from the conduction ratio Ta that outputs the voltage Ea corresponding to the preset tube voltage value kVp set in advance.
  • the output of the power conversion device 11 having such a configuration is controlled by changing the conduction ratio of the power conversion semiconductor switching element IGBT of the inverter circuit 11b according to a tube voltage control signal input to the inverter drive circuit 11c.
  • the system controller 13 is detected by the scan start signal, projection angle signal, scan end signal, tube voltage setting signal, tube current setting signal, X-ray exposure preparation signal, X-ray exposure start signal, and X-ray detector 39.
  • a signal for causing the image processing device 14 to capture X-ray transmission data of the subject, a signal to be displayed on the display device 15, and the like are generated, and the CT scan is controlled using these signals.
  • the logical product circuit 16 outputs the tube voltage preset signal kVp or the tube voltage setting signal kVs to the inverter drive circuit 11c by the logical product of the X-ray exposure start signal Xrs output from the system controller 13 and the tube voltage control signal. It is.
  • the non-contact power transmission means 20 is connected to the output side of the inverter circuit 11b, and is a ring-shaped first iron core disposed on the circumference of the scanner rotating part support frame (not shown) of the gantry of the scanner stationary part 2. Wound around a first winding 20a wound around (not shown) and a ring-shaped second iron core (not shown) formed on the circumference of a rotating frame (not shown) of the scanner rotating unit 2. And a second winding 20b disposed opposite to the first winding and connected to the input side of the high-voltage transformer 30a. The magnetic flux generated in the first winding 20a is configured to interlink with the second winding 20b via the iron cores. Thus, electromagnetic induction power transmission means is configured.
  • the high voltage generator 30 boosts the output voltage of the power converter 11 transmitted from the non-contact power transmission means 20 with a high voltage transformer 30a, and the boosted AC voltage is converted into a direct current with a high voltage rectifier 30b. This is converted to a high voltage, and this high voltage is applied between the anode 31a and the cathode 31b of the X-ray tube 31.
  • the tube voltage detector 32 (tube voltage detection means) detects the tube voltage applied to the X-ray tube 31, and the tube current detector 34 detects the tube current.
  • the tube voltage control device 33 (tube voltage control means) is such that the actual tube voltage value kVd detected by the tube voltage detector 32 and the tube voltage set value kVs output from the system controller 13 match. This controls the conduction ratio of the plurality of power conversion semiconductor switching elements IGBT of the inverter circuit 11b.
  • FIG. 5 is a block diagram showing a functional configuration of the tube voltage control device 33.
  • This tube voltage control unit includes a tube voltage control unit 33A that combines proportional, integral, and differential control elements, and an A / D converter 33d.
  • the tube voltage control unit 33A includes a controller (for example, composed of an MPU) 33a that controls tube voltage, a tube voltage feedback control unit 33b, and a switch 33c.
  • the controller 33a inputs the tube voltage set value signal kVs of the scan condition output from the system controller 13, the X-ray exposure preparation signal Xrr, etc., and also provides a feedback (FB) control system reset signal kVfr to the tube voltage feedback control unit 33b.
  • the tube voltage set value signal kVs is output to the switch 33c as an open / close signal kVsw.
  • the FB control system reset signal kVfr is to reset the integral regulator and the differential regulator to 0 before the tube voltage feedback control is started.
  • the tube voltage feedback control unit 33b includes a first adder circuit 33b1, an integral regulator 33b2, a proportional regulator 33b3, a differential regulator 33b4, and a second adder circuit 33b5, and constitutes a so-called PID control system.
  • the switch 33c outputs the tube voltage control signal kVc to the inverter drive circuit 11c via the optical coupling 40a and the logical product circuit 16.
  • the A / D converter 33d converts the tube voltage detection value kVd output from the tube voltage detector 32 into a digital value.
  • the tube current control device 35 is configured so that the actual tube current value detected by the tube current detector 34 matches the tube current setting value output from the system controller 13. The current flowing through the filament is controlled.
  • This tube current control device 35 insulates the filament heating circuit 35a for generating an AC voltage for heating the filament of the cathode 31 of the X-ray tube 31, and the output AC voltage of the filament heating circuit 35a to insulate the X-ray tube 31. And a filament heating transformer 35b applied to the filament of the cathode 31b.
  • the anode rotation drive device 36 supplies AC power to an anode rotation motor (not shown) for rotating the anode 31a of the X-ray tube 31, and the anode rotation drive device 36 is controlled by an anode rotation / stop signal output from the system controller 13. The rotation / stop of the anode 31a of the X-ray tube 31 is controlled.
  • the high voltage transformer 30a, the high voltage rectifier 30b, the tube voltage detector 32, the tube current detector 34, and the filament heating transformer 35b are housed in a high voltage tank (not shown) and mounted on the scanner rotating unit 2. .
  • the X-ray detector 39 includes an X-ray detector 39a for detecting X-rays transmitted through the subject P, a preamplifier 39b for amplifying the detection value of the X-ray detector 39a, and the output of the preamplifier 39b as digital data. And a data conversion unit 39c for converting the data into serial data for transmission to the image processing device 14.
  • the X-ray detector 39a is formed by arranging a plurality of X-ray detection elements in a single row or a plurality of rows on an arc having a predetermined radius centered on the X-ray tube focal point. Since it is also well-known, detailed description is abbreviate
  • the signal transmission means 40 (non-contact signal transmission means) by optical coupling includes an electrical / optical converter that converts an electrical signal into an optical signal, and an optical / electrical converter that converts an optical signal into an electrical signal.
  • the electrical / optical conversion unit and the optical / electrical conversion unit are arranged between the scanner stationary unit 1 and the scanner rotating unit 2. In this embodiment, four sets of optical couplings are provided.
  • the four sets of optical couplings are optical cups that transmit the tube voltage control signal kVc output from the tube voltage control device 33 to the inverter drive circuit 11c for switching and driving the power conversion semiconductor switching element IGBT of the inverter circuit 11b.
  • Ring 40a X-ray exposure preparation signal Xrr for preparing for X-ray exposure, tube voltage setting signal kVs, tube current setting signal, X-ray tube 31 anode rotation / stop signal, etc.
  • Optical coupling 40c for transmitting a signal and a signal for instructing the X-ray detection unit 39 to take in X-ray detection data to the tube voltage control device 33, the tube current control device 35, the anode rotation drive device 36, and the X-ray detection unit 39
  • the tube voltage control signal kVc is also a feedback control signal for the inverter circuit and needs to be transmitted quickly. For this reason, the tube voltage control signal kVc is transmitted by the optical coupling 40a provided independently. Thereby, the time delay of tube voltage control can be reduced. This also makes it easy to synchronize the imaging of the moving organ of the subject with the biological signal.
  • X-ray control signals including the X-ray exposure preparation signal and X-ray detection data capture instruction signals are converted from parallel data to serial data by the system controller 13 and transmitted via the optical coupling 40c. It is transmitted to the scanner rotation unit 2.
  • the transmitted serial data is converted into parallel data by the serial / parallel converter 37 and input to each device mounted on the scanner rotation unit 2.
  • the X-ray detection data capturing end signal, the monitor signal, and the like are converted into serial data by the parallel / serial converter 38 and transmitted to the system controller 13 through the optical coupling 40d.
  • the subject transmission data detected by the X-ray detector 39a and converted by the data converter 39c is transmitted to the image processing unit by the optical coupling 40e provided solely for exclusive use, similarly to the transmission of the tube voltage control signal. 14 is transmitted.
  • the optical coupling 40e provided solely for exclusive use, similarly to the transmission of the tube voltage control signal. 14 is transmitted.
  • one set of optical coupling for transmitting X-ray detection data to the image processing apparatus is shown, but the number of sets may be increased according to the amount of data to be transmitted or the transmission speed.
  • the first embodiment of the present invention configured as described above uses non-contact power transmission means 20 by electromagnetic induction based on the principle of a rotary transformer for power transmission to the X-ray tube 31, and the tube voltage, tube current, etc.
  • the tube voltage control signal that needs to be controlled in real time and the X-ray detection data that needs to be transmitted continuously are individually dedicated.
  • the signal transmission means is provided, and is distinguished from other signal transmission means.
  • Step S11 The operator uses the operation console 12 to set the tube voltage and tube current, the scan speed (rotation speed of the scanner rotation unit), the X-ray collimation conditions, the scan start and end positions, and the bed on which the subject is placed.
  • the scanning conditions such as the moving speed of the top plate (not shown) or the step feed pitch, the type of reconstruction filter function, and the field of view size (FOV) are set.
  • step S12 Transmission of control signals and control parameters
  • the scan conditions set in step S11 are input to the system controller 13, and control signals and control parameters generated from the system controller 13 based on the scan conditions are sent to the scanner stationary unit 1 and the scanner rotation unit 2 respectively.
  • This control signal includes a preset value of the tube voltage. That is, the control signal and the control parameter include the power conversion device 11 of the scanner stationary unit 1, the image processing device 14, the display device 15, a bed control device that moves and controls a bed on which a subject (not shown) is placed, and a scanner rotation unit. Is sent to a scanner rotation control device (not shown) that controls the rotation drive mechanism (not shown).
  • control signal and the control parameter are the tube voltage control device 33, the tube current control device 35, the anode rotation drive device 36, and the anode rotation drive device 36, which are mounted on the scanner rotation unit 2 through the optical coupling 40c of the non-contact signal transmission means 40. It is transmitted to the X-ray detector 39.
  • Step S13 Preparation for X-ray exposure control
  • the power conversion device 11, the tube voltage control device 33, the tube current control device 35, the anode rotation drive device 36, etc. perform the preparation operation for the X-ray exposure control as shown below. Done.
  • step S131 Judgment of presence / absence of X-ray exposure preparation signal
  • the filament of the cathode 31b of the X-ray tube is heated to a temperature corresponding to the set tube current. It is necessary to rotate the anode 31a.
  • the system controller 13 outputs an X-ray exposure preparation signal Xrr following transmission of the scan conditions.
  • the X-ray exposure preparation signal Xrr output from the system controller 13 is transmitted to the tube voltage control device 33, the tube current control device 35, and the anode rotation drive device 36 via the optical coupling 40c and the serial / parallel converter 37. Is done.
  • the presence or absence of the X-ray exposure preparation signal Xrr is determined by the CPU or MPU of the tube voltage control device 33, the tube current control device 35, and the anode rotation drive device 36. If the transmitted X-ray exposure preparation signal Xrr is present, the process proceeds to the next step S132. If the X-ray exposure preparation signal Xrr is “None”, the X-ray exposure preparation signal Xrr is “Yes”. Wait until
  • step S132 Preparation for X-ray exposure
  • the X-ray exposure preparation signal Xrr is input to the tube current control device 35
  • the X-ray tube filament heating circuit 35a is activated, the tube current set value is taken in from the system controller 13, and the X-ray tube 31 cathode 31b
  • the filament is heated, and the anode 31a of the X-ray tube 31 is rotated at a predetermined rotational speed by an anode rotation signal.
  • Step S133 an X-ray exposure preparation signal Xrr is also input to the tube voltage control device 33 in order to prepare for tube voltage control.
  • the tube voltage preset signal kVp is output from the controller 33a via the switch 33c as the tube voltage control signal kVc.
  • step S134 Setting tube voltage preset value (step S134)
  • the tube voltage preset kVp is input from the tube voltage control system 33A to the AND circuit 16
  • the tube voltage preset signal kVp is output to the inverter drive circuit 11c until the X-ray exposure start signal Xrs is generated. Therefore, the inverter circuit 11b does not start operation.
  • step S14 When a CT scan start command is input to the operation console 12 by the operator, the system controller 13 performs a scan start preparation operation.
  • a signal for rotating the rotating frame of the scanner rotating unit 2 is output from the system controller 13 to the scanner control device (not shown). Then, the rotation frame (not shown) of the scanner rotation unit 2 starts to rotate by a scanner rotation motor (not shown).
  • the scanner rotation motor is connected to a rotary encoder (not shown) for detecting the rotation angle of the rotary frame, and an output pulse from the rotary encoder is measured by a scanner control device (not shown), This is input to the system controller 13.
  • the system controller 13 indicates that the rotation speed of the scanner rotation frame has reached the set value, and the X-ray tube 31 on the rotation frame has reached a predetermined X-ray exposure start position (rotation frame angle).
  • an X-ray exposure start signal Xrs is generated.
  • step S16 X-ray exposure
  • the tube voltage preset signal kVp output from the tube voltage control device 33 at this timing is input to the inverter drive circuit 11c.
  • the inverter circuit 11b starts operating, and the preset tube voltage KVP that does not contribute to the generation of X-rays is applied to the X-ray tube 31.
  • the tube voltage applied to the X-ray tube 31 is detected by the tube voltage detector 32, converted into a digital value by the A / D converter 33d, and input to the controller 33a.
  • the preset tube voltage KVP is not feedback-controlled, but the tube voltage preset value is supplied to the tube voltage control unit 33A as necessary. Feedback control may be performed by transmitting and storing in advance.
  • the preset tube voltage value kVp that does not contribute to the generation of the X-ray is preferably set to about 1 kV when the maximum tube voltage is 150 kV, for example.
  • the controller 33a When the detected tube voltage reaches the preset tube voltage KVP, the controller 33a outputs the FB control system reset signal kVfr, and resets the integral regulator 33b2 and the differential regulator 33b4 of the tube voltage feedback control unit 33b to 0. To do. In addition, measurement of the tube voltage application time is started and a switching signal kVsw for switching the connection of the switch 33c to the output line of the tube voltage feedback control unit 33b is also output.
  • the present embodiment can reduce the switching delay.
  • the tube voltage feedback control unit 33b starts to operate, and the tube voltage set value signal kVs is output from the tube voltage control device 33.
  • the tube voltage set value signal kVs is input to the inverter drive circuit 11c via the optical coupling 40a and the AND circuit 16.
  • the inverter drive circuit 11c causes the power semiconductor switching elements IGBT1 to IGBT4 of the inverter circuit 11b to output a voltage corresponding to the tube voltage set value KVS from the inverter circuit 11b. Control the phase angle. Then, the output voltage of the inverter circuit 11b is input to the high voltage transformer 30a of the high voltage generator 30 via the contactless power transmission means 20, boosted to the tube voltage set value KVS, and input to the high voltage rectifier 30b. Is converted into a DC voltage and applied to the X-ray tube 31. Then, the subject P is irradiated with X-rays from the X-ray tube 31.
  • the tube voltage applied to the X-ray tube 31 is detected by the tube voltage detector 32, input to the tube voltage feedback control unit 33b via the A / D converter 33d of the tube voltage control device 33, and fed back by the PID control system. As a result, the tube voltage value is kept constant at the set value KVS.
  • Step S17 Collection of X-ray detection data
  • the X-ray transmitted through the subject is detected by the X-ray detector 39a.
  • This X-ray detection signal is amplified by a preamplifier 39b, and this amplified detection signal is converted into serial data by a data converter 39c, and image processing is performed via an optical coupling 40e provided exclusively for transmission of X-ray detection data. Is transmitted to the device 14.
  • the system controller 13 continues to monitor the presence or absence of a scan end signal along with the collection status of X-ray detection data, and continues scanning until a scan end signal is input.
  • Step S18 When the X-ray detection data for all views in the entire scan range is detected and transmitted to the image processing device 14 in step S17, a data collection end signal is sent from the image processing device 14 to the system controller 13, thereby the system A scan end signal is generated from the controller 13.
  • This scan end signal is output to each control device (power conversion device 11, tube voltage control device 33, tube current control device 35, etc.), scanner control device, bed control device, etc., related to X-ray control. Then, the operation of each control device is stopped and the CT scan ends.
  • control device power conversion device 11, tube voltage control device 33, tube current control device 35, etc.
  • scanner control device scanner control device
  • bed control device etc.
  • CT image reconstruction (step S19)
  • various correction processes are performed on the X-ray detection data to generate projection data.
  • an image reconstruction operation is performed using the projection data to generate reconstructed image data. Note that the reconstruction of the CT image is not started after the scan is completed, but the image reconstruction can be started as soon as X-ray detection data necessary for the image reconstruction is obtained even during the scan.
  • Step S20 A CT image obtained by performing image display control on the reconstructed image data is displayed on the display device 15 together with incidental information input by the operator from the operation console.
  • an AND circuit is provided in the scanner stationary part, and an X-ray exposure start signal is input to the AND circuit, whereby the voltage applied to the X-ray tube is set from a preset value. Since switching is performed so that the set tube voltage is applied, there is no need to input an X-ray exposure start signal to the tube voltage control device of the scanner rotation unit via optical coupling, resulting in a delay in X-ray exposure timing. Absent.
  • FIG. 9 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to the second embodiment of the present invention.
  • the scanner switch 1 is provided with a changeover switch circuit 17, and the changeover switch circuit 17 supplies the tube voltage to the inverter drive circuit 11c.
  • the point at which the preset signal kVp and the tube voltage set value signal kVs are switched, and the tube voltage preset signal kVp is output from the system controller to the changeover switch circuit 17, and the tube voltage set value signal kVs is output from the tube voltage controller 33 to the changeover switch circuit 17 It is in the point that is output to.
  • the changeover switch circuit 17 includes a tube voltage preset switch 17a and a tube voltage setting switch 17b, and is connected and arranged between the system controller 13 of the scanner stationary unit 1 and the inverter drive circuit 11c. ing.
  • the tube voltage preset signal kVp is input from the system controller 13 to the input terminal of the tube voltage preset switch 17a.
  • the tube voltage control signal kVc output from the tube voltage control device 33 is input to the input terminal of the tube voltage setting switch 17b via the optical coupling 40a.
  • switches 17a and 17b are controlled to operate in reverse so that the switch 17b is turned off when the switch 17a is turned on and the switch 17b is turned off when the switch 17a is turned on.
  • the control signal for turning on the tube voltage preset switch 17a and turning off the tube voltage setting switch 17b is synchronized with the X-ray exposure preparation signal Xrr, and the control signal for turning on the tube voltage setting switch 17b and turning off the tube voltage preset switch 17a.
  • Xrr X-ray exposure preparation signal
  • the control signal for turning on the tube voltage setting switch 17b and turning off the tube voltage preset switch 17a are output from the system controller 13 in synchronism with the scan start signal SCs, and the switches 17a and 17b are turned off while there is no on signal.
  • FIG. 10 is a block diagram showing a functional configuration of the tube voltage control device 33 in the present embodiment.
  • the tube voltage control device 33 of this embodiment includes a tube voltage control unit 33B and an A / D converter 33d.
  • the tube voltage control unit 33B includes a controller 33e and a tube voltage feedback control unit 33b.
  • the controller 33e receives the X-ray exposure preparation signal Xrr, the tube voltage set value signal kVs, and the scan start signal SCs, and the tube voltage set value signal kVs is changed to the tube voltage feedback control unit 33b in response to the input of the scan start signal SCs. Is output to the first adder 33b1.
  • the tube voltage preset switch 17a is turned on by the X-ray exposure preparation signal Xrr output from the system controller 13, and the tube voltage preset signal kVp is input to the inverter drive circuit 11c.
  • the inverter circuit 11b starts operating, and the tube voltage preset value KVP is applied to the X-ray tube 31.
  • the controller 33e outputs the tube voltage set value signal kVs to the tube voltage feedback control unit 33b.
  • the tube voltage control signal kVc that is, the tube voltage set value signal kVs is output to the input terminal of the tube voltage setting switch 17b via the optical coupling 40a.
  • the tube voltage setting switch 17b is in the OFF state at this timing, the tube voltage setting value signal kVs is not output to the inverter drive circuit 11c.
  • the tube voltage setting switch 17b When the scanner rotation unit 2 starts rotating by the scan start signal SCs and the X-ray exposure start signal Xrs is input from the system controller 13 to the tube voltage setting switch 17b, the tube voltage setting switch 17b is turned on and the tube voltage preset switch 17a turns off. As a result, the input to the inverter drive circuit 11c is switched to the tube voltage set value signal kVs, a voltage corresponding to the set tube voltage is output from the inverter circuit 11b, and the tube voltage rapidly rises to the set value KVS.
  • the switching time loss is There is no.
  • FIG. 12 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to the third embodiment of the present invention.
  • the tube voltage preset switch 17a and the tube voltage setting switch 17b of the second embodiment are provided in the tube voltage control unit 33C of the tube voltage control device 33, and as shown in FIG. 12, for X-ray exposure start signal Xrs transmission
  • a non-contact transmission means (40b) is provided exclusively.
  • FIG. 13 is a functional block diagram of the tube voltage control unit 33C of the tube voltage control device 33 of the present embodiment.
  • the operation of the tube voltage control unit 33C is different from the operation of the tube voltage control unit 33A of the first embodiment.
  • the tube voltage preset signal kVp is input to the controller 33f via the optical coupling 40c.
  • This tube voltage preset signal kVp is output to the tube voltage preset switch 17a at the timing when the X-ray exposure preparation signal Xrr is input to the controller 33f, and passes through the tube voltage preset switch 17a which is turned on by the X-ray exposure preparation signal Xrr. This is the point that is output as the tube voltage control signal kVc.
  • the tube voltage preset signal kVp is output to the inverter drive circuit 11c through the optical coupling 40a, and an AC voltage corresponding to the tube voltage preset value is supplied from the inverter circuit 11b to the non-contact power transmission means 20.
  • the second difference between the operation of the tube voltage control unit 33C and the operation of the tube voltage control unit 33A of the first embodiment is that the X-ray exposure start signal Xrs from the system controller 13 is input to the controller 33f, and the tube voltage The setting signal kVs is output to the tube voltage setting switch 17b at the timing when the X-ray exposure start signal Xrs is input to the controller 33f, and is output via the tube voltage setting switch 17b turned on by the X-ray exposure start signal Xrs. It is a point.
  • the X-ray exposure start signal Xrs is transmitted from the scanner rotating unit 2 via the optical coupling 40c, it may interfere with the transmission of other signals, and the X-ray exposure start timing may not be controlled quickly. is assumed. Therefore, a dedicated optical coupling 40b for transmitting the X-ray exposure start signal Xrs from the system controller 13 to the high voltage control device is provided.
  • the tube voltage preset value is set to the controller 33f. It is stored in the storage unit and output to the tube voltage preset switch 17a. Since the tube voltage preset switch 17a is turned on by the tube voltage preset switch on signal output at the timing when the X-ray exposure preparation signal Xrr is input to the controller 33f, the tube voltage preset signal kVp passes through the optical coupling 40a. And output to the inverter drive circuit 11c. As a result, the inverter circuit 11b is driven, and a voltage that does not contribute to X-ray exposure is applied to the X-ray tube 31.
  • the tube voltage preset signal kVp is continuously output to the inverter drive circuit 11c until the X-ray exposure start signal Xrs is input from the system controller 13 and the tube voltage preset switch 17a is turned off.
  • the controller 33f When the X-ray exposure start signal Xrs is input from the system controller 13 to the controller 33f via the optical coupling 40b, the controller 33f outputs a signal for turning off the tube voltage preset switch 17a and turning on the tube voltage setting switch 17b. Is output.
  • an FB control system reset signal kVfr is output from the controller 33f to the tube voltage feedback control unit 33b, and the FB control system is in a state where feedback control is possible.
  • the tube voltage control signal kVc is switched from the tube voltage preset signal kVp to the tube voltage setting signal kVs.
  • the X-ray exposure start signal is transmitted from the system controller to the tube voltage control device via the optical coupling, the X-ray exposure is compared with the first embodiment and the second embodiment. If it is applied to an apparatus that has a slightly low responsiveness at the start of exposure but does not have a high scanning speed, the purpose of simplifying the maintenance and inspection work can be achieved.
  • FIG. 14 is a block diagram showing a schematic configuration of the X-ray CT apparatus according to the fourth embodiment.
  • the fourth embodiment of the present invention is a modification of the third embodiment described above.
  • the difference between the fourth embodiment is that the tube voltage control device 33 of the third embodiment is a scanner in the fourth embodiment. This is a point provided in the stationary part 1.
  • the optical coupling 40a is used to transmit the tube voltage detection value detected by the tube voltage detector 32 to the tube voltage control device 33 provided in the scanner stationary unit 1, and the third The optical coupling 40b provided in this embodiment is not necessary.
  • the tube voltage preset operation and the tube voltage setting operation in the fourth embodiment are the same as those in the third embodiment, but the X-ray exposure start signal Xrs does not pass through optical coupling from the system controller to the scanner stationary unit. Is directly output to the tube voltage control device provided to the X-ray exposure start responsiveness is superior to that of the third embodiment, and is substantially equivalent to the first embodiment and the second embodiment. Responsiveness of starting X-ray exposure is obtained.
  • the fourth embodiment can reduce the weight of the scanner rotating part (reducing the moment of inertia) and is suitable for speeding up the scanner.
  • the X-ray CT apparatus has been described using the first to fourth embodiments.
  • the present invention is not limited to these embodiments, and is the technical idea of the present invention.
  • Control of tube voltage for scanning from the state in which tube voltage that does not contribute to generation of X-rays is applied and power transmission to the tube is made non-contact between transmission of power and signal transmission exchanged between the scanner stationary unit and scanner rotation unit Any form may be used as long as it starts.
  • an X-ray exposure preparation signal output from the system controller is provided separately from the scan conditions in order to perform an X-ray exposure preparation operation including a preset of the tube voltage. It may be replaced with a scan condition setting signal.
  • the drive control signal of the collimator is also transmitted from the system controller of the scanning stationary unit by the non-contact signal transmission means.
  • the non-contact signal transmission means may share a signal transmission device such as a tube voltage and a tube current, or may be provided exclusively.
  • non-contact signal transmission means other means such as an electric field, a magnetic field, an electromagnetic wave or the like may be used instead of the optical coupling.
  • the feedback control of the tube voltage is also possible by a method starting by judging from the current or voltage of the high voltage generator 30 such as the output current or output voltage of the high voltage transformer 30a.
  • the tube voltage has been described with respect to an example in which the operating phase of the switching element of the inverter circuit is controlled, a method of controlling the operating frequency using a resonant inverter circuit, or a combination of the above phase and frequency is used.
  • the converter circuit 11a can be configured to control its output DC voltage, and the converter circuit and inverter circuit can be used together to control the tube voltage.
  • Non-contact signal transmission means 40a-40e optical coupling

Abstract

In order to provide an X-ray CT device that makes high-speed scanning possible by providing a non-contact power transmission means and signal transmission means between a scanner stator and scanner rotor, a non-contact power transmission means, which transmits without contact the output power of an inverter circuit to a scanner rotor, and a non-contact signal transmission means, which transmits without contact a control signal for the control of tube voltage and/or tube current to a scanner stator, an anode drive control signal that controls rotation of an X-ray tube anode, and X-ray detection data that has been detected by an X-ray detector are disposed between the scanner stator and scanner rotor in the X-ray CT device, which is also equipped with a tube voltage preset means, which applies a tube voltage, which does not contribute to X-ray generation, to the X-ray tube, and a tube voltage control initiation means, which starts control of the set tube voltage from a state in which the tube voltage has been preset.

Description

Ｘ線ＣＴ装置X-ray CT system
　本発明は、X線CT装置に係り、特に高速スキャンが可能なX線CT装置に好適な技術に関するものである。 The present invention relates to an X-ray CT apparatus, and more particularly to a technique suitable for an X-ray CT apparatus capable of high-speed scanning.
　X線CT装置は、X線管から扇状又は円錐状もしくは角錐状のX線ビームを様々な投影角度から被検体に照射し、該被検体を透過したX線を前記X線管と対向して配置されたX線検出器で検出し、この検出されたデータを再構成演算して前記被検体の断層像を得るものである。 The X-ray CT apparatus irradiates the subject with a fan-shaped, conical or pyramidal X-ray beam from various projection angles from the X-ray tube, and the X-ray transmitted through the subject is opposed to the X-ray tube. The detected X-ray detector is used for detection, and the detected data is subjected to reconstruction calculation to obtain a tomographic image of the subject.
　このX線CT装置において、”短時間で広い範囲のスキャンが可能である”、”体軸方向に連続したデータが得られ、これによって三次元画像の生成が可能になる”などの特徴により、ヘリカルスキャンやスパイラルスキャンと呼ばれるら旋スキャン方式が用いられている。このら旋スキャンは、X線管からX線を放射しながらX線管とX線検出器が搭載されたスキャナ回転部を回転させるとともに被検体が載置されたテーブルを体軸方向に移動させることによって被検体をら旋状にスキャンするものである。 With this X-ray CT system, features such as “a wide range of scanning is possible in a short time” and “continuous data in the body axis direction can be obtained, which makes it possible to generate a three-dimensional image”. A helical scan method called helical scan or spiral scan is used. In this spiral scan, the X-ray tube and X-ray detector are rotated while rotating the scanner rotating part while radiating X-rays from the X-ray tube, and the table on which the subject is placed is moved in the body axis direction. Thus, the subject is scanned in a spiral shape.
　このようなら旋スキャンを行うために、スキャナ回転部に搭載されたX線管に連続して電力を送電するための電力送電手段と、CTシステム全体を制御するシステムコントローラの制御信号やX線検出器で検出されたデータ等の信号をスキャナ静止部とスキャナ回転部との間でやり取りするための信号伝送手段として、スリップリングとブラシから成る電力送電手段及び信号伝送手段が用いられている。 In this case, in order to perform a rotation scan, power transmission means for continuously transmitting power to the X-ray tube mounted on the scanner rotation unit, and control signals and X-ray detection of the system controller that controls the entire CT system As signal transmission means for exchanging signals such as data detected by the scanner between the scanner stationary part and the scanner rotation part, power transmission means and signal transmission means comprising a slip ring and a brush are used.
　しかし、このようなスリップリングとブラシによる電力送電手段及び信号伝送手段は、スリップリングとブラシの機械的摺接による手段であるので、以下のような問題がある。すなわち、電力送電においては、スリップリングとブラシとの間に大電流が流れることによって、その接触部分に摩耗や腐食が生じ、電力の送電が不安定になる。 However, such power transmission means and signal transmission means using slip rings and brushes are means based on mechanical sliding contact between slip rings and brushes, and thus have the following problems. That is, in power transmission, when a large current flows between the slip ring and the brush, wear or corrosion occurs at the contact portion, and power transmission becomes unstable.
　一方、信号伝送においては、スリップリングとブラシとの接触による磨耗等によって接触不良が発生し、これによる伝送データの棄損が生ずる。 On the other hand, in signal transmission, contact failure occurs due to wear or the like due to contact between the slip ring and the brush, resulting in loss of transmission data.
　このため、上記スリップリングの研磨やブラシの交換などの保守点検作業を定期的に行う必要がある。 Therefore, it is necessary to periodically perform maintenance and inspection work such as polishing the slip ring and replacing the brush.
　そこで，このような問題に対処する方法として，スキャナ静止部とスキャナ回転部との間に電磁誘導作用を利用した電力送電手段を設けて、非接触で電力をスキャナ静止部側からスキャな回転部側へ送電するものが特許文献1に開示されている。また、スキャナ静止部とスキャナ回転部との間で信号やX線検出データを非接触で伝送する手段として、発光素子と受光素子を組み合わせた光カップリングを利用した信号伝送手段を用いたものが特許文献2、特許文献3に開示されている。 Therefore, as a method of coping with such a problem, a power transmission means using electromagnetic induction is provided between the scanner stationary part and the scanner rotating part, and the rotating part that scans power from the scanner stationary part side in a non-contact manner. Patent Document 1 discloses what transmits power to the side. In addition, as a means for transmitting signals and X-ray detection data in a non-contact manner between the scanner stationary part and the scanner rotating part, a signal transmission means using optical coupling combining a light emitting element and a light receiving element is used. It is disclosed in Patent Document 2 and Patent Document 3.
特許第4008010号公報Japanese Patent No. 4008010 特開平2-239734号公報JP-A-2-239734 特開平5-253217号公報Japanese Patent Laid-Open No. 5-253217
　しかしながら、上記特許文献1乃至3には、スキャナ静止部とスキャナ回転部間の電力伝送手段と、信号伝送手段とが単独で開示されているのみである。したがって、スキャナ静止部とスキャナ回転部間で非接触により電力と信号を伝送することにより、従来装置で必要とされたスリップリングやブラシの保守点検作業が不要なX線CT装置を実現するためには更なる創意工夫を必要とする。 However, Patent Documents 1 to 3 only disclose the power transmission means and the signal transmission means between the scanner stationary part and the scanner rotating part. Therefore, in order to realize an X-ray CT system that eliminates the need for maintenance and inspection work of slip rings and brushes required by conventional devices by transmitting power and signals in a non-contact manner between the scanner stationary part and the scanner rotating part. Needs further ingenuity.
　また、X線CT装置においても、他のモダリティと同様に運動臓器の画像診断への適用要求が高く、スキャンの高速化が求められている。 Also, as with other modalities, there is a high demand for applying X-ray CT apparatuses to image diagnosis of moving organs, and high-speed scanning is required.
　しかし、スキャンの高速化を達成するために上記電力送電手段及び信号伝送手段を非接触化すると、非接触信号伝送手段の特性から信号伝送の時間遅れが生じ、X線曝射タイミングの遅れや、X線管の陽極と陰極間に印加される直流高電圧(以下、管電圧と記す)のフィードバック制御への悪影響が懸念される。 However, if the power transmission means and the signal transmission means are made contactless in order to achieve high scanning speed, a signal transmission time delay occurs due to the characteristics of the contactless signal transmission means, and the X-ray exposure timing delay, There is a concern about adverse effects on feedback control of a DC high voltage (hereinafter referred to as tube voltage) applied between the anode and cathode of the X-ray tube.
　すなわち、一例として、管電圧制御信号の伝送に特許文献2に開示された光カップリングを利用した信号伝送手段を用いた場合、電気信号から光信号への変換、光信号から電気信号への変換のための時間遅れもある。特に、システムコントローラをスキャン静止部へ、管電圧制御装置をスキャン回転部へ配置する構成を採ると、管電圧制御に関する信号が光カップリングを往復することとなり、遅延時間の合計が100μsを超えることも想定される。 That is, as an example, when the signal transmission means using optical coupling disclosed in Patent Document 2 is used for transmission of the tube voltage control signal, conversion from an electric signal to an optical signal, conversion from an optical signal to an electric signal There is also a time delay for. In particular, if the system controller is placed in the scan stationary part and the tube voltage control device is placed in the scan rotating part, the signal related to tube voltage control will reciprocate through the optical coupling, and the total delay time will exceed 100 μs. Is also envisaged.
　管電圧のフィードバック制御系におけるPID(比例積分微分)制御系の時間遅れ及び管電圧制御信号伝送の時間遅れの合計が50μsを超えると、前記インバータ回路の動作周波数を20kHzとした場合に、インバータの動作周期は50μsであるので1周期遅れでフィードバック制御が成されることとなり、管電圧の安定した制御が困難となる。前記PID制御系の時間遅れ及び管電圧制御信号伝送の時間遅れの合計が50μsを超えても、管電圧を安定してフィードバック制御できるようにするためには、インバータ回路の動作周波数を20kHzよりも下げれば良いが、そうすると管電圧のリップルが大きくなる。したがって、CT画像の画質が低下することとなる。 When the sum of the time delay of the PID (proportional integral derivative) control system and the time delay of tube voltage control signal transmission in the tube voltage feedback control system exceeds 50 μs, the inverter circuit Since the operation cycle is 50 μs, feedback control is performed with a delay of one cycle, making it difficult to stably control the tube voltage. In order to enable stable feedback control of the tube voltage even when the sum of the time delay of the PID control system and the time delay of the tube voltage control signal transmission exceeds 50 μs, the operating frequency of the inverter circuit is set to be higher than 20 kHz. You can lower it, but doing so will increase the ripple of the tube voltage. Therefore, the image quality of the CT image is degraded.
　本発明は、上記問題に鑑みてなされたものであって、スキャナの静止部とスキャナ回転部との間におけるX線管に供給する電力の送電及びやり取りする信号の伝送を非接触化したX線CT装置を提供することを目的とする。 The present invention has been made in view of the above-described problem, and is an X-ray in which transmission of power supplied to an X-ray tube and transmission of signals to be exchanged between a stationary part of a scanner and a scanner rotation part are made contactless. The purpose is to provide a CT device.
　上記目的を達成するために本発明は、スキャナ静止部とスキャナ回転部と、直流電源と、この直流電源の直流電力を高周波の交流電力に変換するインバータ回路と、このインバータ回路の出力電力を前記スキャナ回転部に非接触で送電する電磁誘導による非接触電力送電手段と、この非接触電力送電手段の出力電圧を昇圧し整流して管電圧を発生する高電圧発生装置と、前記管電圧が印加されて被検体に照射するX線を発生するX線管と、前記被検体を透過した透過X線量を検出するX線検出器と、前記管電圧を制御する管電圧制御装置と、前記X線管とX線検出器とを対向させて前記スキャナ回転部を前記被検体の周りで回転させるスキャナ回転手段と、前記X線検出器によって検出されたデータから前記被検体の断層像を再構成する画像処理装置と、設定されたスキャン条件に基づいて前記各装置及び前記各手段を制御するシステムコントローラとを備えたX線CT装置であって、X線を発生させる管電圧及び／又は管電流の制御に係る制御信号と、前記X線管の陽極の回転を制御する陽極駆動制御信号と、前記X線検出器によって検出されたX線検出データとを、前記スキャナ静止部と前記スキャナ回転部との間において非接触で伝送する非接触信号伝送手段を備えたことを特徴とする。 In order to achieve the above object, the present invention provides a scanner stationary unit, a scanner rotating unit, a DC power source, an inverter circuit that converts DC power of the DC power source into high-frequency AC power, and output power of the inverter circuit as described above. Non-contact power transmission means by electromagnetic induction for non-contact power transmission to the scanner rotation unit, a high voltage generator for boosting and rectifying the output voltage of the non-contact power transmission means to generate a tube voltage, and applying the tube voltage X-ray tube for generating X-rays irradiated to the subject, an X-ray detector for detecting a transmitted X-ray dose transmitted through the subject, a tube voltage control device for controlling the tube voltage, and the X-ray Scanner rotation means for rotating the scanner rotation unit around the subject with the tube and the X-ray detector facing each other, and reconstructing a tomographic image of the subject from data detected by the X-ray detector Image processing device And a system controller that controls each device and each means based on a set scan condition, and relates to control of tube voltage and / or tube current for generating X-rays A control signal, an anode drive control signal for controlling the rotation of the anode of the X-ray tube, and the X-ray detection data detected by the X-ray detector are transmitted between the scanner stationary unit and the scanner rotating unit. Non-contact signal transmission means for non-contact transmission is provided.
　非接触信号伝送手段は、前記非接触信号伝送手段は、電気／光信号変換素子と光／電気信号変換素子とを対向させてなる光カップリングが望ましい。 The non-contact signal transmission means is preferably an optical coupling in which the electrical / optical signal conversion element and the optical / electrical signal conversion element are opposed to each other.
　また管電圧制御装置からインバータ回路へ出力される管電圧制御信号、システムコントローラから管電圧制御装置へ出力されるX線の曝射開始(管電圧の制御の開始)をさせる信号、X線検出器によって検出された被検体のX線検出データの画像処理装置への伝送には、それぞれ専用の非接触信号伝送手段を設けることが望ましい。 Also, tube voltage control signal output from the tube voltage control device to the inverter circuit, X-ray exposure output (start of tube voltage control) output from the system controller to the tube voltage control device, X-ray detector It is desirable to provide dedicated non-contact signal transmission means for transmitting the X-ray detection data of the subject detected by the above to the image processing apparatus.
　このように構成されたX線CT装置は、電源からX線管へ供給される電力の送電と、スキャナ静止部とスキャナ回転部との間の信号伝送とが非接触化されるので、従来のX線CT装置のようなスリップリングの保守作業は不要となる。 In the X-ray CT apparatus configured in this way, the transmission of power supplied from the power source to the X-ray tube and the signal transmission between the scanner stationary part and the scanner rotating part are made non-contact. The maintenance work of the slip ring like the X-ray CT apparatus becomes unnecessary.
　また、本発明は上記の如く構成されたX線CT装置へ、X線発生に寄与しない管電圧を前記X線管に印加しておく管電圧プリセット手段と、前記管電圧がプリセットされた状態から管電圧の制御を開始させる管電圧制御開始手段とを備えたことを特徴とする。 Further, the present invention provides an X-ray CT apparatus configured as described above, a tube voltage presetting means for applying a tube voltage not contributing to X-ray generation to the X-ray tube, and a state in which the tube voltage is preset. It is characterized by comprising tube voltage control starting means for starting tube voltage control.
　前記管電圧プリセット手段と管電圧制御開始手段は、前記スキャナ静止部に設けられた管電圧切替え手段を含み、管電圧プリセット手段はX線曝射開始信号に対応して前記管電圧切替え手段によって管電圧プリセット信号を前記インバータ回路の駆動信号として出力し、管電圧制御開始手段は、管電圧検出値がプリセット値と成った時点で前記管電圧プリセット信号に替えて前記管電圧制御装置から管電圧設定信号をインバータ回路の駆動信号として出力するように構成されることが望ましい。 The tube voltage preset means and the tube voltage control start means include tube voltage switching means provided in the stationary part of the scanner, and the tube voltage preset means responds to the X-ray exposure start signal by the tube voltage switching means. A voltage preset signal is output as a drive signal for the inverter circuit, and the tube voltage control starting means sets the tube voltage from the tube voltage control device in place of the tube voltage preset signal when the tube voltage detection value reaches the preset value. It is desirable to be configured to output the signal as a drive signal for the inverter circuit.
　このように構成されたX線CT装置は、X線管電圧がX線発生に寄与しないプリセット値から設定管電圧へと制御されるのでX線曝射タイミングの時間遅延が小さくできる。 The X-ray CT apparatus configured in this way can reduce the time delay of the X-ray exposure timing because the X-ray tube voltage is controlled from the preset value that does not contribute to X-ray generation to the set tube voltage.
　本発明によれば、X線管に供給する電力の送電とスキャナ静止部とスキャナ回転部間でやり取りする信号伝送とを非接触化すると共にX線の発生に寄与しない管電圧が印加された状態から管電圧のフィードバック制御を開始するようにしたので、X線管に印加される管電圧の制御の時間遅れが短縮されて、高速スキャンが可能と成る。また、前記電力送電手段と信号伝送手段をメンテナンスする時間が短縮されると共に信頼性も向上する。 According to the present invention, the transmission of power supplied to the X-ray tube and the signal transmission exchanged between the scanner stationary unit and the scanner rotating unit are made non-contact and a tube voltage that does not contribute to the generation of X-rays is applied. Since the tube voltage feedback control is started from the above, the time delay of the tube voltage control applied to the X-ray tube is shortened, and high-speed scanning becomes possible. In addition, the maintenance time for the power transmission means and the signal transmission means is shortened and the reliability is improved.
本発明の第1の実施形態のX線CT装置の概略構成を示すブロック図。1 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to a first embodiment of the present invention. インバータ回路の概略構成を示す回路図。The circuit diagram which shows schematic structure of an inverter circuit. インバータ回路の動作説明のタイミングチャート。The timing chart of operation | movement description of an inverter circuit. X線発生に寄与しないプリセット管電圧を発生するインバータの出力電圧とスイッチング素子の導通比率との関係を示す図。The figure which shows the relationship between the output voltage of the inverter which generates the preset tube voltage which does not contribute to X-ray generation, and the conduction | electrical_connection ratio of a switching element. 図1に示すX線CT装置の管電圧制御部の機能構成を示すブロック図。FIG. 2 is a block diagram showing a functional configuration of a tube voltage control unit of the X-ray CT apparatus shown in FIG. 本発明の第1の実施形態のX線CT装置の動作説明用のフローチャート。3 is a flowchart for explaining the operation of the X-ray CT apparatus according to the first embodiment of the present invention. 本発明の第1の実施形態における管電圧制御の動作を説明するフローチャート。3 is a flowchart for explaining the operation of tube voltage control in the first embodiment of the present invention. 本発明の第1の実施形態における管電圧制御の動作を説明するタイミングチャート。3 is a timing chart for explaining the operation of tube voltage control in the first embodiment of the present invention. 本発明の第2の実施形態のX線CT装置の概略構成を示すブロック図。The block diagram which shows schematic structure of the X-ray CT apparatus of the 2nd Embodiment of this invention. 図９に示すX線CT装置の管電圧制御部の機能構成を示すブロック図。The block diagram which shows the function structure of the tube voltage control part of the X-ray CT apparatus shown in FIG. 本発明の第2の実施形態における管電圧制御の動作を説明するタイミングチャート。9 is a timing chart for explaining the operation of tube voltage control in the second embodiment of the present invention. 本発明の第3の実施形態のX線CT装置の概略構成を示すブロック図。FIG. 5 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to a third embodiment of the present invention. 図12に示すX線CT装置の管電圧制御部の機能構成を示すブロック図。FIG. 13 is a block diagram showing a functional configuration of a tube voltage control unit of the X-ray CT apparatus shown in FIG. 本発明の第4の実施形態のX線CT装置の全体構成を示す図。The figure which shows the whole structure of the X-ray CT apparatus of the 4th Embodiment of this invention.
　以下、添付図面に従って本発明のX線CT装置の好ましい実施の形態について詳細に説明する。　
　なお、本発明の実施形態を説明するための全図において、同一機能を有するものは同一符合を付け、その繰り返しの説明は省略する。 Hereinafter, preferred embodiments of the X-ray CT apparatus of the present invention will be described in detail with reference to the accompanying drawings.
Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments of the present invention, and the repetitive description thereof will be omitted.
　《第1の実施形態》
　図1は、本発明の第1の実施形態によるX線CT装置の概略構成を示すブロック図である。本発明の第1の実施形態によるX線CT装置は、図1に示すようにスキャナ静止部1とスキャナ回転部2とで構成される。 First Embodiment
FIG. 1 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to the first embodiment of the present invention. The X-ray CT apparatus according to the first embodiment of the present invention includes a scanner stationary unit 1 and a scanner rotating unit 2 as shown in FIG.
　スキャナ静止部1は、商用電源10から供給される交流電力を前記商用電源10の周波数よりも高い周波数の交流電力に変換する電力変換装置11と、CTシステムの操作に用いられる操作コンソール12と、この操作コンソール12で設定されたスキャン条件に基づいてシステム全体を制御するためのシステムコントローラ13と、後述のX線検出部で検出された被検体のX線透過データを用いてCT画像を生成するための画像再構成手段を有する画像処理装置14と、CT画像及び各種情報を表示する表示装置15と、スキャナ回転部2を回転可能に支持するガントリー(図示省略)と、スキャナ回転部2を回転駆動するスキャナ回転駆動部(図示省略)とを備えて構成される。なお、電力変換装置11とシステムコントローラとの間には、論理積回路16が設けられている。 The scanner stationary unit 1 is a power converter 11 that converts AC power supplied from a commercial power source 10 into AC power having a frequency higher than the frequency of the commercial power source 10, and an operation console 12 that is used to operate the CT system. A CT image is generated by using the system controller 13 for controlling the entire system based on the scanning conditions set by the operation console 12 and the X-ray transmission data of the subject detected by an X-ray detector described later. An image processing device 14 having an image reconstruction means, a display device 15 for displaying CT images and various information, a gantry (not shown) that rotatably supports the scanner rotation unit 2, and a rotation of the scanner rotation unit 2 And a scanner rotation driving unit (not shown) for driving. Note that an AND circuit 16 is provided between the power converter 11 and the system controller.
　また、スキャナ回転部2は、スキャナ静止部1の電力変換装置11から出力された交流電圧を昇圧した後に直流電圧に変換する高電圧発生装置30と、この高電圧発生装置30から出力された直流高電圧が印加されX線を放射するX線管31と、X線管31の陽極31aと陰極31bとの間に印加される電圧(管電圧)を検出する管電圧検出器32と、管電圧を制御する管電圧制御装置33と、前記X線管31の陰極31bのフィラメントに流れる電流(管電流)を検出する管電流検出器34と、前記管電流を制御する管電流制御装置35と、前記X線管31の陽極の回転を制御する陽極回転駆動装置36と、前記X線管31に対し被検体Ｐを間に挟んで対向配置されたX線検出部39と、X線管31から放射されたX線の照射野を可変設定可能なコリメータ(図示省略)と、以上の構成要件を搭載して回転する回転枠(図示省略)とを備えて構成される。 The scanner rotating unit 2 includes a high voltage generator 30 that boosts the AC voltage output from the power converter 11 of the scanner stationary unit 1 and converts the boosted voltage into a DC voltage, and the DC voltage output from the high voltage generator 30. An X-ray tube 31 that emits X-rays when a high voltage is applied, a tube voltage detector 32 that detects a voltage (tube voltage) applied between the anode 31a and the cathode 31b of the X-ray tube 31, and a tube voltage A tube voltage control device 33 for controlling the tube current detector 34 for detecting a current (tube current) flowing in the filament of the cathode 31b of the X-ray tube 31, a tube current control device 35 for controlling the tube current, From the anode rotation driving device 36 for controlling the rotation of the anode of the X-ray tube 31, the X-ray detection unit 39 disposed opposite to the X-ray tube 31 with the subject P interposed therebetween, A collimator (not shown) that can variably set the radiation field of emitted X-rays and a rotating frame (Fig. Configured with the default) and.
　そして、スキャン静止部1とスキャン回転部2との間には、非接触電力送電手段20が配置されるとともに、非接触信号伝送手段40が配置されている。 And, between the scan stationary part 1 and the scan rotating part 2, a non-contact power transmission means 20 and a non-contact signal transmission means 40 are arranged.
　以下、上記構成要件について詳細に説明する。電力変換装置11は、商用電源10から供給される交流電力を直流電力に変換するコンバータ回路11aと、この直流電力を前記商用電源10の周波数よりも高い周波数の交流電力に変換するインバータ回路11bと、このインバータ回路11bを構成する複数の電力変換用半導体スイッチンク素子、例えばIGBT(Insulated Gate Bipolar Transistor;絶縁ゲート型バイポーラトランジスタ)をスイッチング駆動するためのインバータ駆動回路11cとを備えて構成される。 Hereinafter, the above configuration requirements will be described in detail. The power converter 11 includes a converter circuit 11a that converts AC power supplied from the commercial power supply 10 into DC power, and an inverter circuit 11b that converts this DC power into AC power having a frequency higher than the frequency of the commercial power supply 10. The inverter circuit 11b includes a plurality of power conversion semiconductor switching elements, for example, an inverter drive circuit 11c for switching and driving IGBTs (Insulated Gate Bipolar Transistors).
　図2はインバータ回路11bの構成を示している。インバータ回路11bは4個の電力用半導体スイッチング素子IGBT1～IGBT4により全波ブリッジ型回路に構成されている。 Fig. 2 shows the configuration of the inverter circuit 11b. The inverter circuit 11b is configured as a full-wave bridge circuit by four power semiconductor switching elements IGBT1 to IGBT4.
　この全波ブリッジ型回路は、図3(a)に示すように、所定のインバータ動作周波数(1/2T1)、例えば20kHzで動作し、図3(b)～(e)に示すように、インバータ動作周波数の正の半サイクルでは、スイッチング素子IGBT1とIGBT4の導通幅T2が制御され、インバータ動作周波数の負の半サイクルでは、スイッチング素子IGBT2とIGBT3の導通幅T2が制御される。これにより、コンバータ回路11aから供給された直流電圧が任意の高周波交流電圧に変換されてインバータ回路11bから非接触電力送電手段20へ出力される。 As shown in FIG. 3 (a), this full-wave bridge circuit operates at a predetermined inverter operating frequency (1 / 2T1), for example, 20 kHz, and as shown in FIGS. 3 (b) to (e) In the positive half cycle of the operating frequency, the conduction width T2 of the switching elements IGBT1 and IGBT4 is controlled, and in the negative half cycle of the inverter operating frequency, the conduction width T2 of the switching elements IGBT2 and IGBT3 is controlled. As a result, the DC voltage supplied from the converter circuit 11a is converted into an arbitrary high-frequency AC voltage and output from the inverter circuit 11b to the non-contact power transmission means 20.
　なお、前記スイッチング素子IGBT1及びIGBT4の導通幅T2とスイッチング素子IGBT2及びIGBT3の導通幅T2は同じに設定される。 The conduction width T2 of the switching elements IGBT1 and IGBT4 and the conduction width T2 of the switching elements IGBT2 and IGBT3 are set to be the same.
　図４は、前記スイッチング素子IGBT1～IGBT4の導通比率T2/T1とインバータ回路11bの出力電圧(実効値)の関係を示す。図４に示すように、導通比率T2/T1を0から1まで変更することによってインバータ回路11bの出力電圧を0から最大Emaxまで制御することができるが、本実施形態においては、インバータ回路11bは、予め設定されたプリセット管電圧値kVpに対応する電圧Eaを出力する導通比率Taから動作を開始される。 FIG. 4 shows the relationship between the conduction ratio T2 / T1 of the switching elements IGBT1 to IGBT4 and the output voltage (effective value) of the inverter circuit 11b. As shown in FIG. 4, the output voltage of the inverter circuit 11b can be controlled from 0 to the maximum Emax by changing the conduction ratio T2 / T1 from 0 to 1, but in this embodiment, the inverter circuit 11b The operation is started from the conduction ratio Ta that outputs the voltage Ea corresponding to the preset tube voltage value kVp set in advance.
　このような構成の電力変換装置11の出力は、インバータ駆動回路11cへ入力する管電圧の制御信号によってインバータ回路11bの前記電力変換用半導体スイッチング素子IGBTの導通比率を変化させることにより制御される。 The output of the power conversion device 11 having such a configuration is controlled by changing the conduction ratio of the power conversion semiconductor switching element IGBT of the inverter circuit 11b according to a tube voltage control signal input to the inverter drive circuit 11c.
　システムコントローラ13は、スキャン開始信号、投影角度信号、スキャン終了信号、管電圧設定信号、管電流設定信号、X線曝射準備信号、X線曝射開始信号、X線検出部39で検出された被検体のX線透過データを画像処理装置14に取り込ませる信号及び表示装置15に表示する信号等を生成し、これらの信号を用いてCTスキャンの制御を行うものである。 The system controller 13 is detected by the scan start signal, projection angle signal, scan end signal, tube voltage setting signal, tube current setting signal, X-ray exposure preparation signal, X-ray exposure start signal, and X-ray detector 39. A signal for causing the image processing device 14 to capture X-ray transmission data of the subject, a signal to be displayed on the display device 15, and the like are generated, and the CT scan is controlled using these signals.
　論理積回路16は、システムコントローラ13から出力されるX線曝射開始信号Xrsと管電圧制御信号との論理積により管電圧プリセット信号kVp又は管電圧設定信号kVsをインバータ駆動回路11cへ出力させるものである。 The logical product circuit 16 outputs the tube voltage preset signal kVp or the tube voltage setting signal kVs to the inverter drive circuit 11c by the logical product of the X-ray exposure start signal Xrs output from the system controller 13 and the tube voltage control signal. It is.
　非接触電力送電手段20は、前記インバータ回路11bの出力側に接続され前記スキャナ静止部2のガントリーのスキャナ回転部支持部枠(図示省略)の周上に配置されたリング状の第1の鉄心(図示省略)に巻き付けられた第1の巻線20aと、前記スキャナ回転部2の回転枠(図示省略)の周上に形成されたリング状の第2の鉄心(図示省略)に巻きつけられ、前記第1の巻線に対向して配置されると共に前記高電圧変圧器30aの入力側に接続された第2の巻線20bとを有している。そして、前記第1の巻線20aで発生する磁束が前記各鉄心を介して第2の巻線20bに鎖交するように構成されている。これによって、電磁誘導送電手段が構成されている。 The non-contact power transmission means 20 is connected to the output side of the inverter circuit 11b, and is a ring-shaped first iron core disposed on the circumference of the scanner rotating part support frame (not shown) of the gantry of the scanner stationary part 2. Wound around a first winding 20a wound around (not shown) and a ring-shaped second iron core (not shown) formed on the circumference of a rotating frame (not shown) of the scanner rotating unit 2. And a second winding 20b disposed opposite to the first winding and connected to the input side of the high-voltage transformer 30a. The magnetic flux generated in the first winding 20a is configured to interlink with the second winding 20b via the iron cores. Thus, electromagnetic induction power transmission means is configured.
　高電圧発生装置30は、前記非接触電力送電手段20から送電された前記電力変換装置11の出力電圧を高電圧変圧器30aで昇圧し、この昇圧された交流電圧を高電圧整流器30bで直流の高電圧に変換し、この高電圧をX線管31の陽極31aと陰極31b間に印加するものである。 The high voltage generator 30 boosts the output voltage of the power converter 11 transmitted from the non-contact power transmission means 20 with a high voltage transformer 30a, and the boosted AC voltage is converted into a direct current with a high voltage rectifier 30b. This is converted to a high voltage, and this high voltage is applied between the anode 31a and the cathode 31b of the X-ray tube 31.
　管電圧検出器32(管電圧検出手段)は、X線管31に印加される管電圧を検出するものであり、管電流検出器34は管電流を検出するものである。 The tube voltage detector 32 (tube voltage detection means) detects the tube voltage applied to the X-ray tube 31, and the tube current detector 34 detects the tube current.
　管電圧制御装置33(管電圧制御手段)は、前記管電圧検出器32で検出された実際の管電圧値kVdと前記システムコントローラ13から出力された管電圧設定値kVsとが一致するように、前記インバータ回路11bの複数の電力変換用半導体スイッチング素子IGBTの導通比率を制御するものである。 The tube voltage control device 33 (tube voltage control means) is such that the actual tube voltage value kVd detected by the tube voltage detector 32 and the tube voltage set value kVs output from the system controller 13 match. This controls the conduction ratio of the plurality of power conversion semiconductor switching elements IGBT of the inverter circuit 11b.
　図5は、管電圧制御装置33の機能構成を示すブロック図である。この管電圧制御部は、比例、積分、微分の制御要素を組み合わせた管電圧制御部33Aと、A/D変換器33dで構成される。 FIG. 5 is a block diagram showing a functional configuration of the tube voltage control device 33. As shown in FIG. This tube voltage control unit includes a tube voltage control unit 33A that combines proportional, integral, and differential control elements, and an A / D converter 33d.
　管電圧制御部33Aは、管電圧の制御を司るコントローラ(例えばMPUから成る)33aと、管電圧フィードバック制御部33bと、スイッチ33cから成る。コントローラ33aは、システムコントローラ13から出力されたスキャン条件の管電圧設定値信号kVs、X線曝射準備信号Xrr等を入力し、また管電圧フィードバック制御部33bへフィードバック(FB)制御系リセット信号kVfrと管電圧設定値信号kVsを、前記スイッチ33cへその開閉信号kVswを出力するものである。なお、FB制御系リセット信号kVfrは、積分調節器と微分調節器とを管電圧のフィードバック制御が開始される前に0にリセットするものである。 The tube voltage control unit 33A includes a controller (for example, composed of an MPU) 33a that controls tube voltage, a tube voltage feedback control unit 33b, and a switch 33c. The controller 33a inputs the tube voltage set value signal kVs of the scan condition output from the system controller 13, the X-ray exposure preparation signal Xrr, etc., and also provides a feedback (FB) control system reset signal kVfr to the tube voltage feedback control unit 33b. The tube voltage set value signal kVs is output to the switch 33c as an open / close signal kVsw. The FB control system reset signal kVfr is to reset the integral regulator and the differential regulator to 0 before the tube voltage feedback control is started.
　管電圧フィードバック制御部33bは、第1の加算回路33b1、積分調節器33b2、比例調節器33b3、微分調節器33b4、第2の加算回路33b5から成り、いわゆるPID制御系を構成するものである。 The tube voltage feedback control unit 33b includes a first adder circuit 33b1, an integral regulator 33b2, a proportional regulator 33b3, a differential regulator 33b4, and a second adder circuit 33b5, and constitutes a so-called PID control system.
　前記スイッチ33cは、管電圧制御信号kVcを光カップリング40a、論理積回路16を介してインバータ駆動回路11cへ出力するものである。 The switch 33c outputs the tube voltage control signal kVc to the inverter drive circuit 11c via the optical coupling 40a and the logical product circuit 16.
　また、A/D変換器33dは、管電圧検出器32から出力された管電圧検出値kVdをディジタル値に変換するものである。 The A / D converter 33d converts the tube voltage detection value kVd output from the tube voltage detector 32 into a digital value.
　管電流制御装置35は、前記管電流検出器34で検出された実際の管電流値と前記システムコントローラ13から出力された管電流設定値とが一致するように、X線管31の陰極31bのフィラメントに流れる電流を制御するものである。 The tube current control device 35 is configured so that the actual tube current value detected by the tube current detector 34 matches the tube current setting value output from the system controller 13. The current flowing through the filament is controlled.
　この管電流制御装置35は、X線管31の陰極31のフィラメントを加熱するための交流電圧を発生するフィラメント加熱回路35aと、このフィラメント加熱回路35aの出力交流電圧を絶縁してX線管31の陰極31bのフィラメントに印加するフィラメント加熱変圧器35bとで構成される。 This tube current control device 35 insulates the filament heating circuit 35a for generating an AC voltage for heating the filament of the cathode 31 of the X-ray tube 31, and the output AC voltage of the filament heating circuit 35a to insulate the X-ray tube 31. And a filament heating transformer 35b applied to the filament of the cathode 31b.
　陽極回転駆動装置36は、X線管31の陽極31aを回転させるための陽極回転モータ(図示省略)に交流電力を供給するもので、前記システムコントローラ13から出力された陽極の回転/停止信号によって前記X線管31の陽極31aの回転/停止の制御を行うものである。 The anode rotation drive device 36 supplies AC power to an anode rotation motor (not shown) for rotating the anode 31a of the X-ray tube 31, and the anode rotation drive device 36 is controlled by an anode rotation / stop signal output from the system controller 13. The rotation / stop of the anode 31a of the X-ray tube 31 is controlled.
　前記高電圧変圧器30a、高電圧整流器30b、管電圧検出器32、管電流検出器34及びフィラメント加熱変圧器35bは、高電圧タンク(図示省略)に収納されてスキャナ回転部2に搭載される。 The high voltage transformer 30a, the high voltage rectifier 30b, the tube voltage detector 32, the tube current detector 34, and the filament heating transformer 35b are housed in a high voltage tank (not shown) and mounted on the scanner rotating unit 2. .
　X線検出部39は、被検体Pを透過したX線を検出するX線検出器39aと、このX線検出器39aの検出値を増幅するプリアンプ39bと、このプリアンプ39bの出力をディジタルデータに変換し、これを前記画像処理装置14に伝送するためのシリアルデータに変換するデータ変換部39cとで構成される。X線検出器39aは、X線管焦点を中心とし、所定半径を有した円弧上に、複数のX線検出素子を単列又は複数列に配列して成るもので、いずれのタイプの検出器も公知であるので、詳細な説明は省略する。 The X-ray detector 39 includes an X-ray detector 39a for detecting X-rays transmitted through the subject P, a preamplifier 39b for amplifying the detection value of the X-ray detector 39a, and the output of the preamplifier 39b as digital data. And a data conversion unit 39c for converting the data into serial data for transmission to the image processing device 14. The X-ray detector 39a is formed by arranging a plurality of X-ray detection elements in a single row or a plurality of rows on an arc having a predetermined radius centered on the X-ray tube focal point. Since it is also well-known, detailed description is abbreviate | omitted.
　光カップリングによる信号伝送手段40(非接触信号伝送手段)は、電気信号を光信号に変換する電気/光変換部と、光信号を電気信号に変換する光/電気変換部とを備える。電気/光変換部と光/電気変換部は、スキャナ静止部1とスキャナ回転部2との間に配置される。本実施形態では、4組の光カップリングを備えている。 The signal transmission means 40 (non-contact signal transmission means) by optical coupling includes an electrical / optical converter that converts an electrical signal into an optical signal, and an optical / electrical converter that converts an optical signal into an electrical signal. The electrical / optical conversion unit and the optical / electrical conversion unit are arranged between the scanner stationary unit 1 and the scanner rotating unit 2. In this embodiment, four sets of optical couplings are provided.
　4組の光カップリングとは、管電圧制御装置33から出力された管電圧制御信号kVcをインバータ回路11bの電力変換用半導体スイッチング素子IGBTをスイッチング駆動させるためのインバータ駆動回路11cに伝送する光カップリング40aと、X線曝射の準備を行うためのX線曝射準備信号Xrr、管電圧設定信号kVs、管電流設定信号、X線管31の陽極回転/停止信号等のX線制御に係る信号及びX線検出部39にX線検出データの取り込みを指示する信号等を管電圧制御装置33、管電流制御装置35、陽極回転駆動装置36 、X線検出部39に伝送する光カップリング40cと、X線検出データの取り込み終了信号、管電圧制御装置33及び管電流制御装置35等の動作状態をモニタする信号等をシステムコントローラ13に伝送する光カップリング40dと、後述のX線検出部39で検出されたX線検出データを画像処理装置14に伝送する光カップリング40eとを指す。 The four sets of optical couplings are optical cups that transmit the tube voltage control signal kVc output from the tube voltage control device 33 to the inverter drive circuit 11c for switching and driving the power conversion semiconductor switching element IGBT of the inverter circuit 11b. Ring 40a, X-ray exposure preparation signal Xrr for preparing for X-ray exposure, tube voltage setting signal kVs, tube current setting signal, X-ray tube 31 anode rotation / stop signal, etc. Optical coupling 40c for transmitting a signal and a signal for instructing the X-ray detection unit 39 to take in X-ray detection data to the tube voltage control device 33, the tube current control device 35, the anode rotation drive device 36, and the X-ray detection unit 39 An optical coupling 40d for transmitting an X-ray detection data capturing end signal, a signal for monitoring the operation state of the tube voltage control device 33 and the tube current control device 35, etc. to the system controller 13, and an X-ray detection unit described later X-ray detection detected by 39 It refers to the optical coupling 40e that transmits data to the image processing device 14.
　前記管電圧制御信号kVcは、インバータ回路に対するフィードバック制御信号でもあるので迅速に伝送される必要がある。このため、管電圧制御信号kVcは単独に設けられた光カップリング40aによって伝送される。これによって、管電圧制御の時遅れを小さくできる。また、これによって被検体の運動臓器の撮像を生体信号に同期させ易くすることができる。 The tube voltage control signal kVc is also a feedback control signal for the inverter circuit and needs to be transmitted quickly. For this reason, the tube voltage control signal kVc is transmitted by the optical coupling 40a provided independently. Thereby, the time delay of tube voltage control can be reduced. This also makes it easy to synchronize the imaging of the moving organ of the subject with the biological signal.
　また、前記X線曝射準備信号を含む他のX線制御に係る信号及びX線検出データの取り込み指示信号等は、システムコントローラ13でパラレルデータからシリアルデータに変換されて光カプリング40cを介してスキャナ回転部2に伝送される。この伝送されたシリアルデータは、シリアル/パラレル変換器37でパラレルデータに変換されてスキャナ回転部2に搭載された各装置に入力される。 In addition, other X-ray control signals including the X-ray exposure preparation signal and X-ray detection data capture instruction signals are converted from parallel data to serial data by the system controller 13 and transmitted via the optical coupling 40c. It is transmitted to the scanner rotation unit 2. The transmitted serial data is converted into parallel data by the serial / parallel converter 37 and input to each device mounted on the scanner rotation unit 2.
　また、X線検出データの取り込み終了信号及びモニタ信号等は、パラレル/シリアル変換器38でシリアルルデータに変換されて光カプリング40dを介してシステムコントローラ13に伝送される。 Further, the X-ray detection data capturing end signal, the monitor signal, and the like are converted into serial data by the parallel / serial converter 38 and transmitted to the system controller 13 through the optical coupling 40d.
　さらに、X線検出器39aで検出されデータ変換器39cでデータ変換された被検体透過データは、管電圧制御信号の伝送と同様に、専用に単独で設けられた光カップリング40eによって画像処理部14へ伝送される。なお、本実施形態ではX線検出データを画像処理装置へ伝送する光カップリングを1組で示しているが、伝送するデータ量又は伝送速度に応じて組数を増加しても良い。 Further, the subject transmission data detected by the X-ray detector 39a and converted by the data converter 39c is transmitted to the image processing unit by the optical coupling 40e provided solely for exclusive use, similarly to the transmission of the tube voltage control signal. 14 is transmitted. In the present embodiment, one set of optical coupling for transmitting X-ray detection data to the image processing apparatus is shown, but the number of sets may be increased according to the amount of data to be transmitted or the transmission speed.
　上記のように構成された本発明の第1の実施形態は、X線管31への電力送電に回転トランスの原理に基づく電磁誘導による非接触電力送電手段20を用い、管電圧、管電流等のX線制御に係る制御信号及びCT画像の生成に係るX線検出データ等の信号伝送に光カップリングによる信号伝送手段40を用いて、スキャナ静止部1からスキャナ回転部2に送電する電力及びスキャナ静止部1とスキャナ回転部2との間でやり取りする信号の伝送を非接触化するものである。 The first embodiment of the present invention configured as described above uses non-contact power transmission means 20 by electromagnetic induction based on the principle of a rotary transformer for power transmission to the X-ray tube 31, and the tube voltage, tube current, etc. The power transmitted from the scanner stationary unit 1 to the scanner rotating unit 2 using the signal transmission means 40 by optical coupling for signal transmission of control signals related to X-ray control and X-ray detection data related to CT image generation, and Transmission of signals exchanged between the scanner stationary unit 1 and the scanner rotating unit 2 is made non-contact.
　そして、前記光カップリングによる信号伝送手段40において、リアルタイムで制御する必要のある管電圧制御信号と、データを継続して伝送する必要があるX線検出データの伝送に対してはそれぞれ独立した専用の信号伝送手段が設けられ、その他の信号の信号伝送手段と区別される。 In the signal transmission means 40 by the optical coupling, the tube voltage control signal that needs to be controlled in real time and the X-ray detection data that needs to be transmitted continuously are individually dedicated. The signal transmission means is provided, and is distinguished from other signal transmission means.
　次に、図6乃至図8を用いて本実施形態のX線CT装置の動作について説明する。 Next, the operation of the X-ray CT apparatus according to the present embodiment will be described with reference to FIGS.
　(1)スキャン条件の設定(ステップS11)
　操作者は、操作コンソール12を用いて、管電圧及び管電流の設定、スキャン速度(スキャナ回転部の回転速度)、X線コリメーション条件、スキャンの開始位置及び終了位置、被検体を載置する寝台の天板(図示省略)の移動速度又はステップ送りのピッチ、再構成フィルタ関数の種類、視野サイズ(FOV)等のスキャン条件を設定する。 (1) Setting scan conditions (Step S11)
The operator uses the operation console 12 to set the tube voltage and tube current, the scan speed (rotation speed of the scanner rotation unit), the X-ray collimation conditions, the scan start and end positions, and the bed on which the subject is placed. The scanning conditions such as the moving speed of the top plate (not shown) or the step feed pitch, the type of reconstruction filter function, and the field of view size (FOV) are set.
　(2)制御信号及び制御パラメータの伝送(ステップS12)
　ステップS11で設定されたスキャン条件は、システムコントローラ13に入力され、該システムコントローラ13から前記スキャン条件に基づいて生成された制御信号及び制御パラメータがスキャナ静止部1とスキャナ回転部2の各装置に伝送される。この制御信号には、管電圧のプリセット値が含まれる。すなわち、前記制御信号及び制御パラメータは、スキャナ静止部1の電力変換装置11、画像処理装置14、表示装置15、図示省略の被検体を載置する寝台を移動制御する寝台制御装置及びスキャナ回転部の回転駆動機構(図示省略)を制御する図示省略のスキャナ回転制御装置に送られる。また、前記制御信号及び制御パラメータは、非接触信号伝送手段40の光カップリング40cを介してスキャナ回転部2に搭載された管電圧制御装置33、管電流制御装置35、陽極回転駆動装置36及びX線検出部39に伝送される。 (2) Transmission of control signals and control parameters (step S12)
The scan conditions set in step S11 are input to the system controller 13, and control signals and control parameters generated from the system controller 13 based on the scan conditions are sent to the scanner stationary unit 1 and the scanner rotation unit 2 respectively. Is transmitted. This control signal includes a preset value of the tube voltage. That is, the control signal and the control parameter include the power conversion device 11 of the scanner stationary unit 1, the image processing device 14, the display device 15, a bed control device that moves and controls a bed on which a subject (not shown) is placed, and a scanner rotation unit. Is sent to a scanner rotation control device (not shown) that controls the rotation drive mechanism (not shown). Further, the control signal and the control parameter are the tube voltage control device 33, the tube current control device 35, the anode rotation drive device 36, and the anode rotation drive device 36, which are mounted on the scanner rotation unit 2 through the optical coupling 40c of the non-contact signal transmission means 40. It is transmitted to the X-ray detector 39.
　(3)X線曝射制御の準備(ステップS13)
　制御信号及び制御パラメータの伝送が終了すると、電力変換装置11、管電圧制御装置33、管電流制御装置35、陽極回転駆動装置36等において、以下に示すようにX線曝射制御の準備動作が行われる。 (3) Preparation for X-ray exposure control (Step S13)
When the transmission of the control signal and the control parameter is completed, the power conversion device 11, the tube voltage control device 33, the tube current control device 35, the anode rotation drive device 36, etc. perform the preparation operation for the X-ray exposure control as shown below. Done.
　(3－1)X線曝射準備信号の有無の判定(ステップS131)
　X線管31からX線を曝射するためには、X線管31に管電圧を印加する前にX線管の陰極31bのフィラメントを設定管電流に対応した温度に加熱し、X線管の陽極31aを回転させておく必要がある。これらのX線曝射準備動作を行わせるために、システムコントローラ13はスキャン条件の伝送に次いで、X線曝射準備信号Xrrを出力する。 (3-1) Judgment of presence / absence of X-ray exposure preparation signal (step S131)
In order to irradiate X-rays from the X-ray tube 31, before applying a tube voltage to the X-ray tube 31, the filament of the cathode 31b of the X-ray tube is heated to a temperature corresponding to the set tube current. It is necessary to rotate the anode 31a. In order to perform these X-ray exposure preparation operations, the system controller 13 outputs an X-ray exposure preparation signal Xrr following transmission of the scan conditions.
　システムコントローラ13から出力されたX線曝射準備信号Xrrは、光カップリング40c、シリアル/パラレル変換部37を介して、管電圧制御装置33、管電流制御装置35、陽極回転駆動装置36に伝送される。このX線曝射準備信号Xrrの有無が管電圧制御装置33、管電流制御装置35、陽極回転駆動装置36のＣＰＵやＭＰＵで判定される。この伝送されたX線曝射準備信号Xrrが有りの場合は、次のステップS132に進み、X線曝射準備信号Xrrが「無し」の場合は、X線曝射準備信号Xrrが「有り」になるまで待機する。 The X-ray exposure preparation signal Xrr output from the system controller 13 is transmitted to the tube voltage control device 33, the tube current control device 35, and the anode rotation drive device 36 via the optical coupling 40c and the serial / parallel converter 37. Is done. The presence or absence of the X-ray exposure preparation signal Xrr is determined by the CPU or MPU of the tube voltage control device 33, the tube current control device 35, and the anode rotation drive device 36. If the transmitted X-ray exposure preparation signal Xrr is present, the process proceeds to the next step S132. If the X-ray exposure preparation signal Xrr is “None”, the X-ray exposure preparation signal Xrr is “Yes”. Wait until
　(3－2)X線の曝射の準備(ステップS132)
　X線曝射準備信号Xrrが管電流制御装置35へ入力されると、X線管フィラメント加熱回路35aが作動してシステムコントローラ13から管電流設定値が取り込まれ、X線管31の陰極31bのフィラメントが加熱され、また、X線管31の陽極31aは、陽極回転信号によって所定の回転数で回転される。 (3-2) Preparation for X-ray exposure (step S132)
When the X-ray exposure preparation signal Xrr is input to the tube current control device 35, the X-ray tube filament heating circuit 35a is activated, the tube current set value is taken in from the system controller 13, and the X-ray tube 31 cathode 31b The filament is heated, and the anode 31a of the X-ray tube 31 is rotated at a predetermined rotational speed by an anode rotation signal.
　(3－3)管電圧制御の準備(ステップS133)
　一方、管電圧制御装置33にも、管電圧制御の準備のために、X線曝射準備信号Xrrが入力される。X線曝射準備信号Xrrが管電圧制御装置33のコントローラ33aへ入力されると、コントローラ33aからスイッチ33cを介して管電圧プリセット信号kVpが管電圧制御信号kVcとして出力される。 (3-3) Preparation for tube voltage control (Step S133)
On the other hand, an X-ray exposure preparation signal Xrr is also input to the tube voltage control device 33 in order to prepare for tube voltage control. When the X-ray exposure preparation signal Xrr is input to the controller 33a of the tube voltage control device 33, the tube voltage preset signal kVp is output from the controller 33a via the switch 33c as the tube voltage control signal kVc.
　(3－4)管電圧プリセット値のセット(ステップS134)
　一方、論理積回路1６へは、管電圧制御系33Aから管電圧プリセットkVpが入力されているものの、X線曝射開始信号Xrsが発せられるまでは管電圧プリセット信号kVpはインバータ駆動回路11cへ出力されず、したがってインバータ回路11bは動作を開始しない。 (3-4) Setting tube voltage preset value (step S134)
On the other hand, although the tube voltage preset kVp is input from the tube voltage control system 33A to the AND circuit 16, the tube voltage preset signal kVp is output to the inverter drive circuit 11c until the X-ray exposure start signal Xrs is generated. Therefore, the inverter circuit 11b does not start operation.
　(4)スキャン開始準備(ステップS14)
　CTスキャン開始指令が操作者によって操作コンソール12へ入力されると、システムコントローラ13によってスキャン開始の準備動作が行われる。 (4) Scan start preparation (step S14)
When a CT scan start command is input to the operation console 12 by the operator, the system controller 13 performs a scan start preparation operation.
　すなわち、システムコントローラ13からスキャナ制御装置(図示省略)にスキャナ回転部2の回転枠を回転させる信号が出力される。そして、図示省略のスキャナ回転用モータによりスキャナ回転部2の回転枠(図示省略)は回転を開始する。 That is, a signal for rotating the rotating frame of the scanner rotating unit 2 is output from the system controller 13 to the scanner control device (not shown). Then, the rotation frame (not shown) of the scanner rotation unit 2 starts to rotate by a scanner rotation motor (not shown).
　(5)X線曝射開始位置の検出(S15)
　前記スキャナ回転用モータには、前記回転枠の回転角度を検出するためのロータリーエンコーダ(図示省略)が連結されており、該ロータリーエンコーダからの出力パルスがスキャナ制御装置(図示省略)で計測され、これがシステムコントローラ13に入力される。システムコントローラ13は、スキャナ回転枠の回転速度が設定された値に達し、かつ該回転枠上のX線管31が予め決められたX線曝射開始位置(回転枠の角度)になったことが検出されるとX線曝射開始信号Xrsを発生する。 (5) X-ray exposure start position detection (S15)
The scanner rotation motor is connected to a rotary encoder (not shown) for detecting the rotation angle of the rotary frame, and an output pulse from the rotary encoder is measured by a scanner control device (not shown), This is input to the system controller 13. The system controller 13 indicates that the rotation speed of the scanner rotation frame has reached the set value, and the X-ray tube 31 on the rotation frame has reached a predetermined X-ray exposure start position (rotation frame angle). When X is detected, an X-ray exposure start signal Xrs is generated.
　(6)X線の曝射(ステップS16)　
　このX線曝射開始信号Xrsが論理積回路16へ入力されると、このタイミングで管電圧制御装置33から出力されていた管電圧プリセット信号kVpがインバータ駆動回路11cへ入力される。これによって、インバータ回路11bは動作を開始し、X線管31にはX線の発生に寄与しないプリセット管電圧KVPが印加される。 (6) X-ray exposure (step S16)
When this X-ray exposure start signal Xrs is input to the AND circuit 16, the tube voltage preset signal kVp output from the tube voltage control device 33 at this timing is input to the inverter drive circuit 11c. As a result, the inverter circuit 11b starts operating, and the preset tube voltage KVP that does not contribute to the generation of X-rays is applied to the X-ray tube 31.
　X線管31へ印加された管電圧は管電圧検出器32によって検出され、A/D変換器33dによってディジタル値に変換され、コントローラ33aへ入力される。この時点では、管電圧フィードバック制御部33ｂへは目標値とする管電圧に関する信号が入力されないので、プリセット管電圧KVPはフィードバック制御されないが、必要に応じて管電圧制御部33Aへ管電圧プリセット値を予め伝送し、記憶しておくことで、フィードバック制御を行えるようにしても良い。なお、前記X線の発生に寄与しないプリセット管電圧値kVpは、例えば最大管電圧が150kVの場合には1kV程度に設定されることが望ましい。 The tube voltage applied to the X-ray tube 31 is detected by the tube voltage detector 32, converted into a digital value by the A / D converter 33d, and input to the controller 33a. At this time, since the signal related to the target tube voltage is not input to the tube voltage feedback control unit 33b, the preset tube voltage KVP is not feedback-controlled, but the tube voltage preset value is supplied to the tube voltage control unit 33A as necessary. Feedback control may be performed by transmitting and storing in advance. The preset tube voltage value kVp that does not contribute to the generation of the X-ray is preferably set to about 1 kV when the maximum tube voltage is 150 kV, for example.
　そして、コントローラ33aは、検出された管電圧がプリセット管電圧KVPに達すると、FB制御系リセット信号kVfrを出力し、管電圧フィードバック制御部33b の積分調節器33b2と微分調節器33b4を0にリセットする。また、管電圧印加時間の計測を開始すると共に、スイッチ33cを管電圧フィードバック制御部33b の出力ラインへ接続切替えさせる切替え信号kVswをも出力する。この動作において、管電圧がプリセット管電圧KVPへ上昇する時間は数μs程度であるので、X線曝射開始信号Xrsを光カップリングを介してスキャナ静止部2から取り込んで管電圧制御信号を管電圧プリセット信号kVpから管電圧設定値信号kVsへ切替えるよりも、本実施形態の方がその切替えの時遅れを小さくできる。 When the detected tube voltage reaches the preset tube voltage KVP, the controller 33a outputs the FB control system reset signal kVfr, and resets the integral regulator 33b2 and the differential regulator 33b4 of the tube voltage feedback control unit 33b to 0. To do. In addition, measurement of the tube voltage application time is started and a switching signal kVsw for switching the connection of the switch 33c to the output line of the tube voltage feedback control unit 33b is also output. In this operation, since the time for the tube voltage to rise to the preset tube voltage KVP is about several μs, the X-ray exposure start signal Xrs is taken from the scanner stationary unit 2 through optical coupling and the tube voltage control signal is Compared with switching from the voltage preset signal kVp to the tube voltage set value signal kVs, the present embodiment can reduce the switching delay.
　これにより、管電圧フィードバック制御部33bが動作を開始し、管電圧制御装置33から管電圧設定値信号kVsが出力される。この管電圧設定値信号kVsは光カップリング40a、論理積回路16を介してインバータ駆動回路11cへ入力される。 Thereby, the tube voltage feedback control unit 33b starts to operate, and the tube voltage set value signal kVs is output from the tube voltage control device 33. The tube voltage set value signal kVs is input to the inverter drive circuit 11c via the optical coupling 40a and the AND circuit 16.
　管電圧設定値信号kVsが入力されるとインバータ駆動回路11cは、管電圧設定値KVSに対応した電圧がインバータ回路11bから出力されるように、インバータ回路11bの電力用半導体スイッチング素子IGBT1～IGBT4の位相角を制御する。そして、インバータ回路11bの出力電圧は、非接触電力送電手段20を介して高電圧発生装置30の高電圧変圧器30aへ入力され、管電圧設定値KVSへ昇圧され、高電圧整流器30bへ入力されて直流電圧に変換され、X線管31へ印加される。そして、X線管31からX線が被検体Pへ照射される。 When the tube voltage set value signal kVs is input, the inverter drive circuit 11c causes the power semiconductor switching elements IGBT1 to IGBT4 of the inverter circuit 11b to output a voltage corresponding to the tube voltage set value KVS from the inverter circuit 11b. Control the phase angle. Then, the output voltage of the inverter circuit 11b is input to the high voltage transformer 30a of the high voltage generator 30 via the contactless power transmission means 20, boosted to the tube voltage set value KVS, and input to the high voltage rectifier 30b. Is converted into a DC voltage and applied to the X-ray tube 31. Then, the subject P is irradiated with X-rays from the X-ray tube 31.
　X線管31へ印加された管電圧は管電圧検出器32によって検出され、管電圧制御装置33のA/D変換器33dを介して管電圧フィードバック制御部33bへ入力され、PID制御系でフィードバック制御され、管電圧値が設定値KVSに一定に保たれる。 The tube voltage applied to the X-ray tube 31 is detected by the tube voltage detector 32, input to the tube voltage feedback control unit 33b via the A / D converter 33d of the tube voltage control device 33, and fed back by the PID control system. As a result, the tube voltage value is kept constant at the set value KVS.
　(7)X線検出データの収集(ステップS17)
　X線管31から被検体PにX線が照射されると、被検体を透過したX線がX線検出器39aで検出される。このX線検出信号はプリアンプ39bで増幅され、この増幅された検出信号がデータ変換部39cでシリアルデータに変換されてX線検出データの伝送専用に設けられた光カップリング40eを介して画像処理装置14に伝送される。 (7) Collection of X-ray detection data (Step S17)
When the subject P is irradiated with the X-ray from the X-ray tube 31, the X-ray transmitted through the subject is detected by the X-ray detector 39a. This X-ray detection signal is amplified by a preamplifier 39b, and this amplified detection signal is converted into serial data by a data converter 39c, and image processing is performed via an optical coupling 40e provided exclusively for transmission of X-ray detection data. Is transmitted to the device 14.
　システムコントローラ13は、X線検出データの収集状況とともにスキャン終了信号の有無を監視し続け、スキャン終了信号が入力するまでスキャンを続行させる。 The system controller 13 continues to monitor the presence or absence of a scan end signal along with the collection status of X-ray detection data, and continues scanning until a scan end signal is input.
　(8)スキャンの終了(ステップS18)
　上記ステップS17で全スキャン範囲の全ビュー分のX線検出データが検出されて画像処理装置14に伝送されると、画像処理装置14からシステムコントローラ13にデータ収集終了信号が送られ、これによりシステムコントローラ13からスキャン終了信号が発生する。 (8) End of scanning (Step S18)
When the X-ray detection data for all views in the entire scan range is detected and transmitted to the image processing device 14 in step S17, a data collection end signal is sent from the image processing device 14 to the system controller 13, thereby the system A scan end signal is generated from the controller 13.
　このスキャン終了信号は、X線制御に係る各制御装置(電力変換装置11、管電圧制御装置33、管電流制御装置35等)及びスキャナ制御装置、寝台制御装置等へ出力される。そして、各制御装置の動作が停止されCTスキャンが終了する。 This scan end signal is output to each control device (power conversion device 11, tube voltage control device 33, tube current control device 35, etc.), scanner control device, bed control device, etc., related to X-ray control. Then, the operation of each control device is stopped and the CT scan ends.
　(9)CT画像の再構成(ステップS19)
　X線検出データが入力された画像処理装置14において、このX線検出データに各種の補正処理が施されて投影データが生成される。そして、この投影データを用いて画像再構成演算が行われて再構成画像データが生成される。なお、上記CT画像の再構成は、スキャン終了後に開始するのでなく、スキャン中であっても、画像再構成に必要なX線検出データが得られ次第に、画像再構成を開始することもできる。 (9) CT image reconstruction (step S19)
In the image processing apparatus 14 to which the X-ray detection data is input, various correction processes are performed on the X-ray detection data to generate projection data. Then, an image reconstruction operation is performed using the projection data to generate reconstructed image data. Note that the reconstruction of the CT image is not started after the scan is completed, but the image reconstruction can be started as soon as X-ray detection data necessary for the image reconstruction is obtained even during the scan.
　(10)画像表示(ステップS20)
　前記再構成画像データに画像表示制御が施されて得られたCT画像が、操作コンソールから操作者によって入力された付帯情報とともに、表示装置15に表示される。 (10) Image display (Step S20)
A CT image obtained by performing image display control on the reconstructed image data is displayed on the display device 15 together with incidental information input by the operator from the operation console.
　本発明の第1の実施形態によれば、スキャナ静止部に論理積回路を設け、X線曝射開始信号を論理積回路へ入力することで、X線管へ印加される電圧をプリセット値から設定管電圧が印加されるように切り替えるので、光カップリングを介してスキャナ回転部の管電圧制御装置へX線曝射開始信号を入力せずとも良いので、X線曝射タイミングの遅れが生じない。 According to the first embodiment of the present invention, an AND circuit is provided in the scanner stationary part, and an X-ray exposure start signal is input to the AND circuit, whereby the voltage applied to the X-ray tube is set from a preset value. Since switching is performed so that the set tube voltage is applied, there is no need to input an X-ray exposure start signal to the tube voltage control device of the scanner rotation unit via optical coupling, resulting in a delay in X-ray exposure timing. Absent.
　《第2の実施形態》
　図9は、本発明の第2の実施形態によるX線CT装置の概略構成を示すブロック図である。本発明の第2の実施形態が、前記第1の実施形態と異なる部分は、スキャナ静止部1に切替えスイッチ回路17が設けられ、この切替えスイッチ回路17でインバータ駆動回路11cへ供給される管電圧プリセット信号kVpと管電圧設定値信号kVsを切替える点と、管電圧プリセット信号kVpはシステムコントローラから切替えスイッチ回路17へ出力され、また管電圧設定値信号kVsは管電圧制御装置33から切替えスイッチ回路17へ出力されるようになっている点にある。 << Second Embodiment >>
FIG. 9 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to the second embodiment of the present invention. The difference between the second embodiment of the present invention and the first embodiment is that the scanner switch 1 is provided with a changeover switch circuit 17, and the changeover switch circuit 17 supplies the tube voltage to the inverter drive circuit 11c. The point at which the preset signal kVp and the tube voltage set value signal kVs are switched, and the tube voltage preset signal kVp is output from the system controller to the changeover switch circuit 17, and the tube voltage set value signal kVs is output from the tube voltage controller 33 to the changeover switch circuit 17 It is in the point that is output to.
　切替えスイッチ回路17は、図9に示すように、管電圧プリセットスイッチ17aと、管電圧設定スイッチ17bとから成り、スキャナ静止部1のシステムコントローラ13とインバータ駆動回路11cとの間に接続、配置されている。そして、管電圧プリセットスイッチ17aの入力端子には、管電圧プリセット信号kVpがシステムコントローラ13から入力される。一方、管電圧設定スイッチ17bの入力端子には、管電圧制御装置33から出力される管電圧制御信号kVcが光カップリング40aを介して入力される。 As shown in FIG. 9, the changeover switch circuit 17 includes a tube voltage preset switch 17a and a tube voltage setting switch 17b, and is connected and arranged between the system controller 13 of the scanner stationary unit 1 and the inverter drive circuit 11c. ing. The tube voltage preset signal kVp is input from the system controller 13 to the input terminal of the tube voltage preset switch 17a. On the other hand, the tube voltage control signal kVc output from the tube voltage control device 33 is input to the input terminal of the tube voltage setting switch 17b via the optical coupling 40a.
　これらのスイッチ17aと17bは、スイッチ17aがオンする時にはスイッチ17bがオフし、スイッチ17aがオンする時にはスイッチ17bがオフするというように逆作動するように制御される。 These switches 17a and 17b are controlled to operate in reverse so that the switch 17b is turned off when the switch 17a is turned on and the switch 17b is turned off when the switch 17a is turned on.
　管電圧プリセットスイッチ17aをオンさせ管電圧設定スイッチ17bをオフさせる制御信号はX線曝射準備信号Xrrと同期して、また管電圧設定スイッチ17bをオンさせ管電圧プリセットスイッチ17aをオフさせる制御信号はスキャン開始信号SCsと同期してシステムコントローラ13から出力され、それらのオン信号がない間はそれらのスイッチ17a、17bはオフ状態となる。 The control signal for turning on the tube voltage preset switch 17a and turning off the tube voltage setting switch 17b is synchronized with the X-ray exposure preparation signal Xrr, and the control signal for turning on the tube voltage setting switch 17b and turning off the tube voltage preset switch 17a. Are output from the system controller 13 in synchronism with the scan start signal SCs, and the switches 17a and 17b are turned off while there is no on signal.
　図10は、本実施形態における管電圧制御装置33の機能構成を示すブロック図である。図に示すように、本実施形態の管電圧制御装置33は、管電圧制御部33BとA/D変換器33dとから成る。管電圧制御部33Bは、コントローラ33eと管電圧フィードバック制御部33bとから成る。コントローラ33eには、X線曝射準備信号Xrr、管電圧設定値信号kVs並びにスキャン開始信号SCsが入力され、スキャン開始信号SCsの入力に応じて管電圧設定値信号kVsが管電圧フィードバック制御部33bの第1の加算器33b1へ出力されるようになっている。 FIG. 10 is a block diagram showing a functional configuration of the tube voltage control device 33 in the present embodiment. As shown in the figure, the tube voltage control device 33 of this embodiment includes a tube voltage control unit 33B and an A / D converter 33d. The tube voltage control unit 33B includes a controller 33e and a tube voltage feedback control unit 33b. The controller 33e receives the X-ray exposure preparation signal Xrr, the tube voltage set value signal kVs, and the scan start signal SCs, and the tube voltage set value signal kVs is changed to the tube voltage feedback control unit 33b in response to the input of the scan start signal SCs. Is output to the first adder 33b1.
　上記第2の実施形態の動作を説明する。図11のタイムチャートに示すように、システムコントローラ13から出力されるX線曝射準備信号Xrrによって管電圧プリセットスイッチ17aがオンさせられ、管電圧プリセット信号kVpがインバータ駆動回路11cへ入力される。これによって、インバータ回路11ｂが動作を開始し、管電圧プリセット値KVPがX線管31に印加される。 The operation of the second embodiment will be described. As shown in the time chart of FIG. 11, the tube voltage preset switch 17a is turned on by the X-ray exposure preparation signal Xrr output from the system controller 13, and the tube voltage preset signal kVp is input to the inverter drive circuit 11c. As a result, the inverter circuit 11b starts operating, and the tube voltage preset value KVP is applied to the X-ray tube 31.
　次いで、システムコントローラ13からスキャン開始信号SCsが出力されると、管電圧制御装置33において、コントローラ33eが管電圧設定値信号kVsを管電圧フィードバック制御部33bへ出力する。これによって、管電圧制御信号kVc、すなわち管電圧設定値信号kVsが光カップリング40aを介して管電圧設定スイッチ17bの入力端子へ出力される。しかし、このタイミングでは管電圧設定スイッチ17bはオフ状態にあるので、管電圧設定値信号kVsがインバータ駆動回路11cへ出力されることはない。 Next, when the scan start signal SCs is output from the system controller 13, in the tube voltage control device 33, the controller 33e outputs the tube voltage set value signal kVs to the tube voltage feedback control unit 33b. As a result, the tube voltage control signal kVc, that is, the tube voltage set value signal kVs is output to the input terminal of the tube voltage setting switch 17b via the optical coupling 40a. However, since the tube voltage setting switch 17b is in the OFF state at this timing, the tube voltage setting value signal kVs is not output to the inverter drive circuit 11c.
　スキャン開始信号SCsによってスキャナ回転部2が回転を始め、X線曝射開始信号Xrsがシステムコントローラ13から管電圧設定スイッチ17bへ入力されると、管電圧設定スイッチ17bがオンし、管電圧プリセットスイッチ17aがオフする。これによって、インバータ駆動回路11cへの入力が管電圧設定値信号kVsに切り替わり、インバータ回路11bから設定管電圧に対応した電圧が出力され、管電圧は設定値KVSへと急激に上昇する。 When the scanner rotation unit 2 starts rotating by the scan start signal SCs and the X-ray exposure start signal Xrs is input from the system controller 13 to the tube voltage setting switch 17b, the tube voltage setting switch 17b is turned on and the tube voltage preset switch 17a turns off. As a result, the input to the inverter drive circuit 11c is switched to the tube voltage set value signal kVs, a voltage corresponding to the set tube voltage is output from the inverter circuit 11b, and the tube voltage rapidly rises to the set value KVS.
　本第2の実施形態によれば、管電圧をプリセット値KVPから設定値KVSへ切替えるための信号をシステムコントローラ13からスキャナ静止部へ設けた切替えスイッチ回路17へ直接に出力するので、切り替えのタイムロスがない。 According to the second embodiment, since the signal for switching the tube voltage from the preset value KVP to the set value KVS is directly output from the system controller 13 to the changeover switch circuit 17 provided in the scanner stationary portion, the switching time loss is There is no.
　《第3の実施形態》
　図12は、本発明の第3の実施形態によるX線CT装置の概略構成を示すブロック図である。本発明の第3の実施形態は、管電圧のプリセット及びX線曝射のための制御をスキャナ回転部2へ搭載された管電圧制御装置33において行うために、図13に示すように、前記第2の実施形態の管電圧プリセットスイッチ17a及び管電圧設定スイッチ17bを管電圧制御装置33の管電圧制御部33Cへ設けるとともに、図12に示すように、X線曝射開始信号Xrs伝送用の非接触伝送手段(40ｂ)を専用に設けたものである。 << Third Embodiment >>
FIG. 12 is a block diagram showing a schematic configuration of an X-ray CT apparatus according to the third embodiment of the present invention. In the third embodiment of the present invention, in order to perform tube voltage presetting and control for X-ray irradiation in the tube voltage control device 33 mounted on the scanner rotating unit 2, as shown in FIG. The tube voltage preset switch 17a and the tube voltage setting switch 17b of the second embodiment are provided in the tube voltage control unit 33C of the tube voltage control device 33, and as shown in FIG. 12, for X-ray exposure start signal Xrs transmission A non-contact transmission means (40b) is provided exclusively.
　図13は、本実施形態の管電圧制御装置33の管電圧制御部33Cの機能ブロック図である。この管電圧制御部33Cの動作が第1の実施形態の管電圧制御部33Aの動作と異なる点は、第1に、コントローラ33fへ管電圧プリセット信号kVpが光カップリング40cを介して入力され、この管電圧プリセット信号kVpはX線曝射準備信号Xrrがコントローラ33ｆへ入力したタイミングで管電圧プリセットスイッチ17aへ出力され、X線曝射準備信号Xrrでオンとなる管電圧プリセットスイッチ17aを介して管電圧制御信号kVcとして出力される点である。 FIG. 13 is a functional block diagram of the tube voltage control unit 33C of the tube voltage control device 33 of the present embodiment. The operation of the tube voltage control unit 33C is different from the operation of the tube voltage control unit 33A of the first embodiment.First, the tube voltage preset signal kVp is input to the controller 33f via the optical coupling 40c. This tube voltage preset signal kVp is output to the tube voltage preset switch 17a at the timing when the X-ray exposure preparation signal Xrr is input to the controller 33f, and passes through the tube voltage preset switch 17a which is turned on by the X-ray exposure preparation signal Xrr. This is the point that is output as the tube voltage control signal kVc.
　この管電圧プリセット信号kVpは光カップリング40aを介してインバータ駆動回路11cへ出力され、インバータ回路11bから管電圧プリセット値に応じた交流電圧が非接触電力送電手段20へ供給される。 The tube voltage preset signal kVp is output to the inverter drive circuit 11c through the optical coupling 40a, and an AC voltage corresponding to the tube voltage preset value is supplied from the inverter circuit 11b to the non-contact power transmission means 20.
　管電圧制御部33Cの動作が第1の実施形態の管電圧制御部33Aの動作と異なる点の2番目は、システムコントローラ13からのX線曝射開始信号Xrsがコントローラ33fへ入力され、管電圧設定信号kVsはX線曝射開始信号Xrsがコントローラ33fへ入力したタイミングで管電圧設定スイッチ17bへ出力され、X線曝射開始信号Xrsによってオンさせられた管電圧設定スイッチ17bを介して出力される点である。 The second difference between the operation of the tube voltage control unit 33C and the operation of the tube voltage control unit 33A of the first embodiment is that the X-ray exposure start signal Xrs from the system controller 13 is input to the controller 33f, and the tube voltage The setting signal kVs is output to the tube voltage setting switch 17b at the timing when the X-ray exposure start signal Xrs is input to the controller 33f, and is output via the tube voltage setting switch 17b turned on by the X-ray exposure start signal Xrs. It is a point.
　X線曝射開始信号Xrsをスキャナ回転部2から光カップリング40cを介して伝送すると、その他の信号の伝送と干渉して、X線曝射開始のタイミングを迅速に制御できない場合が生ずることも想定される。このため、X線曝射開始信号Xrsをシステムコントローラ13から高電圧制御装置へ伝送する専用の光カップリング40bが設けられている。 If the X-ray exposure start signal Xrs is transmitted from the scanner rotating unit 2 via the optical coupling 40c, it may interfere with the transmission of other signals, and the X-ray exposure start timing may not be controlled quickly. is assumed. Therefore, a dedicated optical coupling 40b for transmitting the X-ray exposure start signal Xrs from the system controller 13 to the high voltage control device is provided.
　この第3の実施形態では、システムコントローラ13からX線曝射準備信号Xrrとともに管電圧プリセット信号kVpが光カップリング40cを介して管電圧制御装置33へ入力すると、管電圧プリセット値がコントローラ33fの記憶部へ記憶されるとともに管電圧プリセットスイッチ17aへ出力される。管電圧プリセットスイッチ17aはX線曝射準備信号Xrrがコントローラ33fへ入力したタイミングで出力された管電圧プリセットスイッチオン信号でオンさせられているので、管電圧プリセット信号kVpが光カップリング40aを介して、インバータ駆動回路11cへ出力される。これにより、インバータ回路11bが駆動され、X線管31にX線曝射に寄与しない電圧が印加される。 In the third embodiment, when the tube voltage preset signal kVp is input from the system controller 13 together with the X-ray exposure preparation signal Xrr to the tube voltage control device 33 via the optical coupling 40c, the tube voltage preset value is set to the controller 33f. It is stored in the storage unit and output to the tube voltage preset switch 17a. Since the tube voltage preset switch 17a is turned on by the tube voltage preset switch on signal output at the timing when the X-ray exposure preparation signal Xrr is input to the controller 33f, the tube voltage preset signal kVp passes through the optical coupling 40a. And output to the inverter drive circuit 11c. As a result, the inverter circuit 11b is driven, and a voltage that does not contribute to X-ray exposure is applied to the X-ray tube 31.
　そして、管電圧プリセット信号kVpはX線曝射開始信号Xrsがシステムコントローラ13から入力して、管電圧プリセットスイッチ17aがオフするまでインバータ駆動回路11cへ出力され続ける。 The tube voltage preset signal kVp is continuously output to the inverter drive circuit 11c until the X-ray exposure start signal Xrs is input from the system controller 13 and the tube voltage preset switch 17a is turned off.
　そして、光カップリング40bを介してシステムコントローラ13からX線曝射開始信号Xrsがコントローラ33fへ入力されると、コントローラ33fから管電圧プリセットスイッチ17aをオフし管電圧設定スイッチ17bをオンさせる信号が出力される。これと同時に、コントローラ33fからFB制御系リセット信号kVfrが管電圧フィードバック制御部33bへ出力され、FB制御系がフィードバック制御可能な状態と成る。これによって、管電圧制御信号kVcが管電圧プリセット信号kVpから管電圧設定信号kVsへ切り替えられる。 When the X-ray exposure start signal Xrs is input from the system controller 13 to the controller 33f via the optical coupling 40b, the controller 33f outputs a signal for turning off the tube voltage preset switch 17a and turning on the tube voltage setting switch 17b. Is output. At the same time, an FB control system reset signal kVfr is output from the controller 33f to the tube voltage feedback control unit 33b, and the FB control system is in a state where feedback control is possible. As a result, the tube voltage control signal kVc is switched from the tube voltage preset signal kVp to the tube voltage setting signal kVs.
　この第3の実施形態は、X線曝射開始信号をシステムコントローラから光カップリングを介して管電圧制御装置へ伝送するので、第1の実施形態及び第2の実施形態と比較し、X線曝射開始の応答性が若干低いが、スキャン速度がそれほど速くない装置へ適用すれば、保守点検作業の簡易化という目的は叶えられる。 In the third embodiment, since the X-ray exposure start signal is transmitted from the system controller to the tube voltage control device via the optical coupling, the X-ray exposure is compared with the first embodiment and the second embodiment. If it is applied to an apparatus that has a slightly low responsiveness at the start of exposure but does not have a high scanning speed, the purpose of simplifying the maintenance and inspection work can be achieved.
　《第4の実施形態》
　次に、本発明の第4の実施形態を説明する。図14は、この第4の実施形態によるX線CT装置の概略構成を示すブロック図である。本発明の第4の実施形態は上記第3の実施形態を変形したもので、それらの間で大きく異なる点は、第4の実施形態では、第3の実施形態の管電圧制御装置33がスキャナ静止部1に設けられている点である。 << Fourth Embodiment >>
Next, a fourth embodiment of the present invention will be described. FIG. 14 is a block diagram showing a schematic configuration of the X-ray CT apparatus according to the fourth embodiment. The fourth embodiment of the present invention is a modification of the third embodiment described above. The difference between the fourth embodiment is that the tube voltage control device 33 of the third embodiment is a scanner in the fourth embodiment. This is a point provided in the stationary part 1.
　したがって、第4の実施形態では光カップリング40aは管電圧検出器32によって検出された管電圧検出値をスキャナ静止部1に設けられた管電圧制御装置33へ伝送するために用いられ、第3の実施形態が備える光カップリング40bは不要となる。 Therefore, in the fourth embodiment, the optical coupling 40a is used to transmit the tube voltage detection value detected by the tube voltage detector 32 to the tube voltage control device 33 provided in the scanner stationary unit 1, and the third The optical coupling 40b provided in this embodiment is not necessary.
　この第4の実施形態における管電圧プリセット動作並びに管電圧設定動作は上記第3の実施形態と同様であるが、X線曝射開始信号Xrsが光カップリングを介さないでシステムコントローラからスキャナ静止部へ設けられた管電圧制御装置へ直接に出力されるので、X線曝射開始の応答性が第3の実施形態よりも優れ、上記第1の実施形態と第2の実施形態とほぼ同等のX線曝射開始の応答性が得られる。また、この第4の実施形態は、管電圧制御装置がスキャナ静止部へ設けられているので、スキャナ回転部の軽量化が計れ(慣性モーメントが小さくなり)、スキャナの高速化に好適である。 The tube voltage preset operation and the tube voltage setting operation in the fourth embodiment are the same as those in the third embodiment, but the X-ray exposure start signal Xrs does not pass through optical coupling from the system controller to the scanner stationary unit. Is directly output to the tube voltage control device provided to the X-ray exposure start responsiveness is superior to that of the third embodiment, and is substantially equivalent to the first embodiment and the second embodiment. Responsiveness of starting X-ray exposure is obtained. In addition, since the tube voltage control device is provided in the scanner stationary part, the fourth embodiment can reduce the weight of the scanner rotating part (reducing the moment of inertia) and is suitable for speeding up the scanner.
　以上、本発明によるX線CT装置について第1乃至第4の実施形態を用いて説明したが、本発明は、これらの実施形態に限定されるものではなく、本発明の技術思想である、X線管に供給する電力の送電とスキャナ静止部とスキャナ回転部間でやり取りする信号伝送とを非接触化すると共にX線の発生に寄与しない管電圧が印加された状態からスキャン用管電圧の制御を開始するものであれば、どのような形態でも良い。 As described above, the X-ray CT apparatus according to the present invention has been described using the first to fourth embodiments. However, the present invention is not limited to these embodiments, and is the technical idea of the present invention. Control of tube voltage for scanning from the state in which tube voltage that does not contribute to generation of X-rays is applied and power transmission to the tube is made non-contact between transmission of power and signal transmission exchanged between the scanner stationary unit and scanner rotation unit Any form may be used as long as it starts.
　例えば、以下のように変形されるものでも可能である。 For example, it can be modified as follows.
　(1)上記実施形態では、管電圧のプリセットを含むX線曝射準備動作を行うために、スキャン条件とは別にシステムコントローラから出力されるX線曝射準備信号を設けているが、これはスキャン条件の設定信号で置換しても良い。 (1) In the above embodiment, an X-ray exposure preparation signal output from the system controller is provided separately from the scan conditions in order to perform an X-ray exposure preparation operation including a preset of the tube voltage. It may be replaced with a scan condition setting signal.
　(2)X線照射野を可変設定するコリメータの制御信号について説明を省略しているが、コリメータの駆動制御信号についても非接触信号伝送手段によりスキャン静止部のシステムコントローラから伝送するようにすると良い。この場合の非接触信号伝送手段は、管電圧、管電流等の信号伝送用の物を共用しても良いし、又は専用に設けても良い。 (2) Although description of the control signal of the collimator that variably sets the X-ray irradiation field is omitted, it is preferable that the drive control signal of the collimator is also transmitted from the system controller of the scanning stationary unit by the non-contact signal transmission means. . In this case, the non-contact signal transmission means may share a signal transmission device such as a tube voltage and a tube current, or may be provided exclusively.
　(3)非接触信号伝送手段として、光カップリングに替えて他の手段、例えば、電界、磁界、電磁波等による手段を用いても良い。 (3) As the non-contact signal transmission means, other means such as an electric field, a magnetic field, an electromagnetic wave or the like may be used instead of the optical coupling.
　(4)管電圧のフィードバック制御は、高電圧変圧器30aの出力電流又は出力電圧等の高電圧発生装置30の電流または電圧から判断して開始する方法でも可能である。 (4) The feedback control of the tube voltage is also possible by a method starting by judging from the current or voltage of the high voltage generator 30 such as the output current or output voltage of the high voltage transformer 30a.
　(5)管電圧は、インバータ回路のスイッチング素子の動作位相が制御される例について説明したが、共振型インバータ回路を用いて、その動作周波数を制御する方法や、前記位相と周波数とを併用して制御する方法、コンバータ回路11aをその出力直流電圧を制御可能に構成して、該コンバータ回路とインバータ回路とを併用して管電圧を制御する構成も可能である。 (5) Although the tube voltage has been described with respect to an example in which the operating phase of the switching element of the inverter circuit is controlled, a method of controlling the operating frequency using a resonant inverter circuit, or a combination of the above phase and frequency is used. The converter circuit 11a can be configured to control its output DC voltage, and the converter circuit and inverter circuit can be used together to control the tube voltage.
　(6)インバータ回路の直流電源の電力は、三相交流電源から供給される例について説明したが、X線管に要求される電力が可能であれば、単相交流電源やバッテリィから供給しても良い。 (6) Although the example in which the power of the DC power supply of the inverter circuit is supplied from a three-phase AC power supply has been described, if the power required for the X-ray tube is possible, supply it from a single-phase AC power supply or a battery. Also good.
　1　スキャナ静止部、　2　スキャナ回転部、　11b　インバータ回路、　11c　インバータ駆動回路、　12　操作コンソール、　13　システムコントローラ、14　画像処理装置、　16　論理積回路、17　切替えスイッチ回路、　20　非接触電力送電手段、　30a　高電圧変圧器、　30b　高電圧整流器、　31　X線管、　32　管電圧検出器、　33　管電圧制御装置、34　管電流検出器、　35　管電流制御装置、　36　陽極回転駆動装置、　39　X線検出部、　40　非接触信号伝送手段、　40a～40e　光カップリング 1 scanner stationary part, 2 scanner rotating part, 11b inverter circuit, 11c inverter drive circuit, 12 operation console, 13 system controller, 14 image processing device, 16 AND circuit, 17 changeover switch circuit, 20 non-contact power transmission means, 30a High voltage transformer, 30b high voltage rectifier, 31 X-ray tube, 32 tube voltage detector, 33 tube voltage control device, 34 tube current detector, 35 tube current control device, 36 anode rotation drive device, 39 X-ray detection unit , 40 Non-contact signal transmission means, 40a-40e optical coupling

Claims (13)

  1. 　スキャナ静止部とスキャナ回転部と、直流電源と、この直流電源の直流電力を高周波の交流電力に変換するインバータ回路と、このインバータ回路の出力電力を前記スキャナ回転部に非接触で送電する電磁誘導による非接触電力送電手段と、この非接触電力送電手段の出力電圧を昇圧し整流して管電圧を発生する高電圧発生装置と、前記管電圧が印加されて被検体に照射するX線を発生するX線管と、前記被検体を透過した透過X線量を検出するX線検出器と、前記管電圧を制御する管電圧制御装置と、前記X線管とX線検出器とを対向させて前記スキャナ回転部を前記被検体の周りで回転させるスキャナ回転手段と、前記X線検出器によって検出されたデータから前記被検体の断層像を再構成する画像処理装置と、設定されたスキャン条件に基づいて前記各装置及び前記各手段を制御するシステムコントローラとを備えたX線CT装置であって、
    　X線を発生させる管電圧及び/又は管電流の制御に係る制御信号と、前記X線管の陽極の回転を制御する陽極駆動制御信号と、前記X線検出器によって検出されたX線検出データとを、前記スキャナ静止部と前記スキャナ回転部との間において非接触で伝送する非接触信号伝送手段を備えたことを特徴とするX線CT装置。     Scanner stationary unit, scanner rotating unit, DC power source, inverter circuit for converting DC power of the DC power source into high frequency AC power, and electromagnetic induction for transmitting output power of the inverter circuit to the scanner rotating unit in a contactless manner Generates a tube voltage by boosting and rectifying the output voltage of the contactless power transmission means, and generating X-rays to which the tube voltage is applied to irradiate a subject An X-ray tube, an X-ray detector that detects a transmitted X-ray dose that has passed through the subject, a tube voltage control device that controls the tube voltage, and the X-ray tube and the X-ray detector facing each other. A scanner rotation unit that rotates the scanner rotation unit around the subject, an image processing device that reconstructs a tomographic image of the subject from data detected by the X-ray detector, and a set scan condition On the basis of An X-ray CT apparatus provided with a system controller for controlling each device and each means,
    Control signal for controlling tube voltage and / or tube current for generating X-ray, anode drive control signal for controlling rotation of anode of X-ray tube, and X-ray detection data detected by X-ray detector An X-ray CT apparatus comprising non-contact signal transmission means for transmitting non-contact between the scanner stationary part and the scanner rotating part.
  2. 　前記非接触信号伝送手段は、電気/光信号変換素子と光/電気信号変換素子とを対向させてなる光カップリングであることを特徴とする請求項1に記載のX線CT装置。 2. The X-ray CT apparatus according to claim 1, wherein the non-contact signal transmission means is an optical coupling in which an electrical / optical signal conversion element and an optical / electrical signal conversion element are opposed to each other.
  3. 　前記管電圧制御装置はスキャナ回転部に配置され、この管電圧制御装置から出力された管電圧設定信号は、管電圧設定信号の伝送専用に設けられた非接触信号伝送手段を介してスキャナ静止部へ伝送されることを特徴とする請求項1又は2に記載のX線CT装置。 The tube voltage control device is disposed in the scanner rotation unit, and the tube voltage setting signal output from the tube voltage control device is connected to the scanner stationary unit via non-contact signal transmission means provided exclusively for transmission of the tube voltage setting signal. The X-ray CT apparatus according to claim 1, wherein the X-ray CT apparatus is transmitted to the X-ray CT apparatus.
  4. 　前記システムコントローラから管電圧制御装置へ伝送されるX線曝射開始信号は、X線曝射開始信号の伝送専用に設けられた非接触信号伝送手段を介して管電圧制御装置へ伝送されることを特徴とする請求項1乃至3にいずれか一項に記載のX線CT装置。 The X-ray exposure start signal transmitted from the system controller to the tube voltage control device is transmitted to the tube voltage control device through non-contact signal transmission means provided exclusively for transmission of the X-ray exposure start signal. The X-ray CT apparatus according to any one of claims 1 to 3, wherein
  5. 　前記管電圧制御装置はスキャナ静止部に設けられ、管電圧検出器によって検出された管電圧検出値が前記非接触信号伝送手段によって前記管電圧制御装置へ伝送されることを特徴とする請求項1又は2に記載のX線CT装置。 2. The tube voltage control device is provided in a stationary part of the scanner, and a tube voltage detection value detected by a tube voltage detector is transmitted to the tube voltage control device by the non-contact signal transmission means. Or the X-ray CT apparatus of 2.
  6. 　前記X線検出器で検出されたX線検出データは、X線検出データの伝送専用に設けられた前記非接触信号伝送手段を介して画像処理装置へ伝送されることを特徴とする請求項1乃至5のいずれか一項に記載のX線CT装置。 2. The X-ray detection data detected by the X-ray detector is transmitted to the image processing apparatus via the non-contact signal transmission means provided exclusively for transmission of the X-ray detection data. The X-ray CT apparatus as described in any one of thru | or 5.
  7. 　前記スキャナ回転部には、前記管電圧制御装置に加え、管電流制御装置とX線管陽極回転駆動装置も搭載され、前記システムコントローラからこれらの3つの装置へ発せられる信号のうち前記X線曝射開始信号を除く制御信号は共用の非接触信号伝送手段により伝送されることを特徴とする請求項4に記載のX線CT装置。 In addition to the tube voltage control device, the scanner rotation unit is also equipped with a tube current control device and an X-ray tube anode rotation drive device, and the X-ray exposure among the signals emitted from the system controller to these three devices. 5. The X-ray CT apparatus according to claim 4, wherein control signals other than the firing start signal are transmitted by a common non-contact signal transmission means.
  8. 　X線発生に寄与しない管電圧を前記X線管に印加しておく管電圧プリセット手段と、前記管電圧がプリセットされた状態から管電圧の制御を開始させる管電圧制御開始手段とを備えたことを特徴とする請求項1に記載のX線CT装置。 Tube voltage presetting means for applying a tube voltage not contributing to X-ray generation to the X-ray tube, and tube voltage control starting means for starting tube voltage control from a state in which the tube voltage is preset. The X-ray CT apparatus according to claim 1, wherein:
  9. 　前記管電圧プリセット手段と管電圧制御開始手段は、前記スキャナ静止部に設けられた管電圧切替え手段を含み、管電圧プリセット手段はX線曝射開始信号に対応して管電圧切替え手段によって管電圧プリセット信号を前記インバータ回路の駆動信号として出力し、管電圧制御開始手段は、管電圧検出値がプリセット値と成った時点で前記管電圧プリセット信号に替えて前記管電圧制御装置から管電圧設定信号をインバータ回路の駆動信号として出力することを特徴とする請求項8に記載のX線CT装置。 The tube voltage preset means and the tube voltage control start means include tube voltage switching means provided in the scanner stationary part, and the tube voltage preset means responds to the X-ray exposure start signal by the tube voltage switching means. A preset signal is output as a drive signal for the inverter circuit, and the tube voltage control start means replaces the tube voltage preset signal when the tube voltage detection value becomes a preset value, and the tube voltage control signal from the tube voltage control device. 9. The X-ray CT apparatus according to claim 8, wherein: is output as a drive signal for the inverter circuit.
  10. 　前記管電圧プリセット手段と管電圧制御開始手段とは、前記スキャナ静止部に設けられた論理積回路を含むことを特徴とする請求項9に記載のX線CT装置。 10. The X-ray CT apparatus according to claim 9, wherein the tube voltage preset unit and the tube voltage control start unit include an AND circuit provided in the scanner stationary unit.
  11. 　前記システムコントローラはスキャナ静止部へ配置され、管電圧プリセット信号を論理積回路へ出力し、前記管電圧制御装置はスキャナ回転部へ配置され、管電圧設定信号は非接触信号伝送手段を介して前記論理積回路へ出力されることを特徴とする請求項8に記載のX線CT装置。 The system controller is disposed in the scanner stationary part, and outputs a tube voltage preset signal to the AND circuit, the tube voltage control device is disposed in the scanner rotating part, and the tube voltage setting signal is transmitted through the non-contact signal transmission means. 9. The X-ray CT apparatus according to claim 8, wherein the X-ray CT apparatus is output to a logical product circuit.
  12. 　前記管電圧切替え手段は、前記管電圧プリセット信号の入力端子を有し、X線曝射準備信号によってオンし管電圧プリセット信号を出力する第1のスイッチと、前記管電圧設定信号の入力端子を有し、X線曝射開始信号によってオンし管電圧設定信号を出力する第2のスイッチとから成ることを特徴とする請求項9に記載のX線CT装置。 The tube voltage switching means has an input terminal for the tube voltage preset signal, a first switch that is turned on by an X-ray exposure preparation signal and outputs a tube voltage preset signal, and an input terminal for the tube voltage setting signal 10. The X-ray CT apparatus according to claim 9, further comprising a second switch that is turned on by an X-ray exposure start signal and outputs a tube voltage setting signal.
  13. 　前記管電圧切替え手段は、スキャナ回転部へ設けられた前記管電圧制御装置に含まれることを特徴とする請求項12に記載のX線CT装置。 13. The X-ray CT apparatus according to claim 12, wherein the tube voltage switching means is included in the tube voltage control device provided in a scanner rotating unit.
PCT/JP2009/064959 2008-09-02 2009-08-27 X-ray ct device WO2010026914A1 (en)

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