X-ray computer tomography apparatus

• US 20010008552A1
• Filed: 01/17/2001
• Published: 07/19/2001
• Est. Priority Date: 01/17/2000
• Status: Active Grant

• Current Assignee: Toshiba Medical Systems Corporation (Canon Inc.)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Harada, Sanae, Harada, Toyoshige
• Granted Patent: US 6,674,836 B2
• Time in Patent Office: Days
• US Class Current: 378/107
• CPC Class Codes: A61B 6/56 Details of data transmission or power supply, e.g. use of slip rings
• CPC Class Codes: H05G 1/10 Power supply arrangements for feeding the X-ray tube supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623

Abstract

An X-ray computer tomography apparatus comprises a high-voltage transformer which performs the increase and noncontacting transmission of the power simultaneously and outputs a desired high voltage for causing X rays to be generated at the rotatable gantry section. The high-voltage transformer is divided into a primary-side which is provided on the static gantry section and to which the output of a frequency converting circuit is supplied and a secondary-side which generates a high voltage. A capacitor is connected to a secondary coil of the high-voltage transformer, thereby forming a resonance circuit.

Claims

1. An X-ray computer tomography apparatus comprising:

a static gantry section;

a rotatable gantry section which is provided on said static gantry section in a rotatable manner and has an X-ray tube for generating X rays;

a frequency converting circuit which is connected to an alternating-current power source and converts the output voltage from the alternating-current power source into a desired high-frequency voltage;

a high-voltage transformer which transmits the output of said frequency converting circuit from said static gantry section to said rotatable gantry section and steps up the output to a desired high voltage; and

a rectifier circuit which converts the alternating-current voltage outputted from said high-voltage transformer into a direct-current voltage and supplies the direct-current voltage to said X-ray tube, wherein

said high-voltage transformer including;

a primary-side which is provided on said static gantry section and to which the output of said frequency converting circuit is supplied, and a resonance circuit with a capacitor connected to a winding of a secondary-side, which is provided on said rotatable gantry section and generates said high voltage.

2. The X-ray computer tomography apparatus according to

claim 1

, wherein

said frequency converting circuit includes a converter which converts the output voltage from said alternating-current power source into a direct-current voltage, and

at least one inverter which converts the direct-current voltage outputted from said converter into said high-frequency alternating-current voltage.

3. The X-ray computer tomography apparatus according to

claim 1

, wherein said primary-side of said high-voltage transformer is placed on a circumference of said static gantry section, and

said secondary-side of said high-voltage transformer is placed on the circumference of said rotatable gantry section having the same center as that of said static gantry section and rotates in no contact with said primary-side, while facing said primary-side.

4. The X-ray computer tomography apparatus according to

claim 1

, wherein said primary-side of said high-voltage transformer is composed of a primary side core and a primary winding wound around the primary side core and connected to the output terminal of said frequency converting circuit, and

said secondary-side of said high-voltage transformer is composed of a secondary side core and a secondary winding wound around the secondary side core and connected to the input terminal of said rectifier circuit.

5. The X-ray computer tomography apparatus according to

claim 4

, wherein at least one of said primary side core and said secondary side core having an open face.

6. The X-ray computer tomography apparatus according to

claim 1

, wherein said primary-side of said high-voltage transformer including:

a primary-side pair which is composed of a plurality of primary side cores and a plurality of primary windings wound around the respective primary side cores, and a plurality of units of the primary-side pair being provided on the circumference on said static gantry section.

7. The X-ray computer tomography apparatus according to

claim 6

, wherein said primary side core is shaped like a rectangle one side of which is cut out and has open face long in the direction of said circumference.

8. The X-ray computer tomography apparatus according to

claim 1

, wherein the secondary-side of said high-voltage transformer including:

a secondary-side pair which is composed of a plurality of secondary side cores and a plurality of secondary windings wound around the respective secondary side cores, and a plurality of units of the secondary-side pair being provided on the circumference on said rotatable gantry section.

9. The X-ray computer tomography apparatus according to

claim 8

, wherein said secondary side core is shaped like a rectangle one side of which is cut out and has open face long in the direction of said circumference.

10. An X-ray computer tomography apparatus comprising:

a static gantry section;

a rotatable gantry section which has an X-ray tube for radiating X rays and is rotatable with respect to said static gantry section; and

power transmission section which transmits power from said static gantry section to said rotatable gantry section in a noncontacting manner, wherein said power transmission section includes a high-voltage transformer that steps up said power and has such a divided structure as has its primary side on said static gantry section and its secondary side on said rotatable gantry section.

12. The X-ray computer tomography apparatus according to

claim 10

, wherein the secondary side of said high-voltage transformer rotates with respect to the primary side of said high-voltage transformer as said rotatable gantry section rotates.

13. The X-ray computer tomography apparatus according to

claim 10

, wherein said static gantry section includes a power source, a converter for converting the voltage from the power source into a direct-current voltage, and one or more inverters for converting said direct-current voltage into an alternating-current voltage, and

said rotatable gantry section includes a rectifier for rectifying the output voltage stepped up by said high-voltage transformer into a direct-current high voltage and outputting the direct-current high voltage to said X-ray tube.

14. The X-ray computer tomography apparatus according to

claim 10

, wherein the primary side of said high-voltage transformer is composed of a plurality of primary-coil-wound primary side cores arranged so as to form a circumference as a whole, and

the secondary side of said high-voltage transformer is provided with secondary-coil-wound secondary side cores arranged so as to face said primary side cores.

15. The X-ray computer tomography apparatus according to

claim 14

, wherein the secondary side of said high-voltage transformer further includes a resonance circuit that resonates with the inductance of said secondary coils.

16. The X-ray computer tomography apparatus according to

claim 14

, wherein the shape of and the number of said secondary side cores are so determined that all of said plurality of primary side cores never fail to said secondary side cores, even when said rotary section rotates.

17. The X-ray computer tomography apparatus according to

claim 14

, wherein said plurality of primary sides of said high-voltage transformer are connected in parallel via said inverters, and

said plurality of secondary sides of said high-voltage transformer are connected in series via said rectifier.

18. The X-ray computer tomography apparatus according to

claim 14

, wherein said secondary-coil-wound secondary side cores are evenly arranged on the secondary side of said high-voltage transformer.

19. The X-ray computer tomography apparatus according to

claim 15

, wherein the primary side of said high-voltage transformer further includes another resonance circuit that resonates with the inductance of said primary coils.

11. An X-ray computer tomography apparatus comprising:

a static gantry section;

a rotatable gantry section which has an X-ray tube for radiating X rays and is rotatable with respect to said static gantry section; and

power transmission section which transmits power from said static gantry section to said rotatable gantry section in a noncontacting manner, wherein said rotatable gantry section does not have the primary side of said high-voltage transformer for stepping up power.

20. An X-ray computer tomography apparatus comprising:

a static gantry section having an imaging volume;

a rotatable gantry section mounted opposed to the static gantry section, which rotates around the imaging volume;

an alternating-current power source provided in the static gantry section;

a plurality of primary coils which are arranged around the imaging volume of the static gantry section and electrically connected to the alternating-current power source;

a plurality of primary side cores to each of which the respective primary coils is wound;

a plurality of secondary side cores arranged on the rotatable gantry section so as to oppose to the primary cores;

a plurality of secondary cores which are wound around the respective secondary side cores;

a plurality of resonance circuits one of which is connected to each one of the secondary cores;

a rectifier circuit which rectifies the outputs of the resonance circuits; and

an X-ray tube connected to the rectifier circuit.