X-ray CT apparatus and X-ray tube

• US 20050053189A1
• Filed: 08/23/2004
• Published: 03/10/2005
• Est. Priority Date: 09/05/2003
• Status: Active Grant

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Hagiwara, Akira, Gohno, Makoto
• Granted Patent: US 7,187,756 B2
• Time in Patent Office: Days
• US Class Current: 378/16
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4028 resulting in acquisition of views from substantially different positions, e.g. EBCT
• CPC Class Codes: A61B 6/4035 the source being combined with a filter or grating
• CPC Class Codes: A61B 6/405 Source units specially adapted to modify characteristics of the beam during the data acquisition process A61B6/4021, A61B6/4035 take precedence
• CPC Class Codes: A61B 6/482 involving multiple energy imaging
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: H01J 2235/086 Target geometry
• CPC Class Codes: H01J 35/10 Rotary anodes; Arrangements for rotating anodes; Cooling rotary anodes
• CPC Class Codes: H01J 35/153 Spot position control

Abstract

An X-ray CT apparatus capable of imaging a subject based on X-rays of multiple energy levels while using an ordinary X-ray detector includes an X-ray tube which generates X-rays from multiple focal points of different 3-dimensional positions sequentially on a time-division basis, a plurality of filters which implement the filtering individually for the X-rays generated individually from the focal points, a collimator which equalizes the irradiation range of the X-rays generated individually from the focal points, collection means which collects projection data of multiple views of a subject of imaging for the X-rays generated individually from the focal points, and reconstruction means which reconstructs an image based on the projection data. The anode of the X-ray tube has multiple impingement portions where electrons released by the cathode impinge at multiple positions on the trajectory of electrons sequentially on a time-division basis.

Claims

1. An X-ray CT apparatus comprising:

an X-ray tube which generates X-rays from multiple focal points of different 3-dimensional positions sequentially on a time-division basis;

a plurality of filters which implement the filtering individually for the X-rays generated individually from the focal points;

a collimator which equalizes the irradiation range of the X-rays generated individually from the focal points;

a collection device which collects projection data of multiple views of a subject of imaging for the X-rays generated individually from the focal points; and

a reconstruction device which reconstructs an image based on the projection data.

2. An X-ray CT apparatus according to claim 1, wherein:

said X-ray tube comprises an X-ray tube having an anode and a cathode which confront each other and generating X-rays from focal points on said anode where electrons from said cathode impinge, and

said anode has multiple impingement portions where electrons released by said cathode impinge at multiple positions on the trajectory of electrons sequentially on a time-division basis.

3. An X-ray CT apparatus according to claim 2, wherein said anode comprises a plurality of rotary plates which are parallel to each other and share a rotation shaft which is parallel to the trajectory of electrons, at least rotary plates located from the position nearest to said cathode up to the position immediately before the position farthest from said cathode each having large-radius sections with a radius larger than the distance from the rotation center to the trajectory of electrons and small-radius sections with a radius smaller than the distance from the rotation center to the trajectory of electrons by being formed alternately along the rotational direction such that the large-radius sections of said rotary plates do not overlap in the direction parallel to the trajectory of electron beam.

4. An X-ray CT apparatus according to claim 3, wherein said multiple rotary plates comprise two rotary plates.

5. An X-ray CT apparatus according to claim 2, wherein:

said anode comprises two rotary plates which are parallel to each other and share a rotation shaft which is parallel to the trajectory of electrons released by said cathode, said rotary plates having X-ray generation sections and X-ray non-generation sections which are laid out on the surfaces of opposite sides alternately along the rotational direction such that the X-ray generation sections on the surfaces of opposite sides do not overlap in the direction parallel to the rotation shaft, and

said cathode generates electrons which impinge on the surfaces of opposite sides of said two rotary plates.

6. An X-ray CT apparatus according to claim 2 including a plurality of pairs of said anode and cathode.

7. An X-ray CT apparatus according to claim 6 including two pairs of said anode and cathode.

8. An X-ray CT apparatus according to claim 6, wherein said focal points are all located on the same horizontal plane.

9. An X-ray CT apparatus according to claim 6, wherein said focal points are all located on a plane which is aslant against the horizontal plane.

10. An X-ray tube including an anode and a cathode which confront each other and generating X-rays from focal points on said anode where electrons from said cathode impinge,

said anode having multiple impingement portions where electrons released by said cathode impinge at multiple positions on the trajectory of electrons sequentially on a time-division basis.

11. An X-ray tube according to claim 10, wherein said anode comprises a plurality of rotary plates which are parallel to each other and share a rotation shaft which is parallel to the trajectory of electrons, at least rotary plates located from the position nearest to said cathode up to the position immediately before the position farthest from said cathode each having large-radius sections with a radius larger than the distance from the rotation center to the trajectory of electrons and small-radius sections with a radius smaller than the distance from the rotation center to the trajectory of electrons by being formed alternately along the rotational direction such that the large-radius sections of said rotary plates do not overlap in the direction parallel to the trajectory of electron beam.

12. An X-ray tube according to claim 11, wherein said multiple rotary plates comprise two rotary plates.

13. An X-ray tube according to claim 10, wherein:

said anode comprises two rotary plates which are parallel to each other and share a rotation shaft which is parallel to the trajectory of electrons released by said cathode, said rotary plates having X-ray generation sections and X-ray non-generation sections laid out on the surfaces of opposite sides alternately along the rotational direction such that the X-ray generation sections on the surfaces of opposite sides do not overlap in the direction parallel to the rotation shaft, and

said cathode generates electrons which impinge on to the surfaces of opposite sides of said two rotary plates.

14. An X-ray tube according to any one of claim 10 through claim 13 including a plurality of pairs of said anode and cathode.

15. An X-ray tube according to claim 14 including two pairs of said anode and cathode.

16. An X-ray tube according to claim 14, wherein said focal points are all located on the same horizontal plane.

17. An X-ray tube according to claim 14, wherein said focal points are all located on a plane which is aslant against the horizontal plane.