CT imaging system with multiple peak x-ray source

• US 7,778,382 B2
• Filed: 08/18/2006
• Issued: 08/17/2010
• Est. Priority Date: 06/05/2003
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hoffman, David M.
• Primary Examiner(s): Ho; Allen C.
• Application Number:
  US11/465,472
• Publication Number:
  US 20060285645A1
• Time in Patent Office: 1,460 Days
• Field of Search: 378/5, 378/9, 378/16, 378/19, 378/122, 378/124, 378/125, 378/134, 378/156, 378/157, 378/158, 378/159, 378/98.9, 378/98.11
• US Class Current: 378/5
• CPC Class Codes: A61B 6/027 characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4007 characterised by using a plurality of source units
• CPC Class Codes: A61B 6/4021 involving movement of the focal spot
• CPC Class Codes: A61B 6/4035 the source being combined with a filter or grating
• CPC Class Codes: A61B 6/4241 using energy resolving detectors, e.g. photon counting
• CPC Class Codes: A61B 6/482 involving multiple energy imaging
• CPC Class Codes: H01J 2235/068 Multi-cathode assembly
• CPC Class Codes: H01J 35/064 Details of the emitter, e.g. material or structure H01J35/065 takes precedence

Abstract

An x-ray source (32) for performing energy discrimination within an imaging system (10) includes a cathode-emitting device (82) for emitting electrons and an anode (81) that has a target (80) whereupon the electrons impinge to generate an x-ray beam (93) with multiple x-ray quantity energy peaks (116 and 120). A method of performing energy discrimination in the imaging system (10) includes emitting the electrons. The x-ray beam (93) with the x-ray quantity energy peaks (116 and 120) is generated. The x-ray beam (93) is directed through an object (44) and is thereafter received. An x-ray image having multiple energy differentiable characteristics is generated in response to the x-ray beam (93) as received.

Claims

1. A method of scanning a patient, said method comprising the steps of

(a) establishing a first electron-accelerating voltage potential between a first cathode and an anode;

(b) establishing a second electron-accelerating voltage potential between a second cathode and said anode;

(c) emitting a first plurality of electrons from said first cathode and toward said anode so that said first plurality of electrons impinge on said anode and thereby generate a first x-ray beam;

(d) emitting a second plurality of electrons from said second cathode and toward said anode so that said second plurality of electrons impinge on said anode and thereby generate a second x-ray beam;

(e) directing first x-ray beam and said second x-ray beam in alternating pulses through a filter device so as to form an alternating pulse composite x-ray beam;

(f) directing said alternating pulse composite x-ray beam through said patient and thereafter receiving said alternating pulse composite x-ray beam with a detector so as to accordingly generate x-ray signals; and

(g) generating an x-ray image in response to said x-ray signals;

wherein said first electron-accelerating voltage potential has a characteristic first kilovolt peak, said second electron-accelerating voltage potential has a characteristic second kilovolt peak, and said second kilovolt peak is different from said first kilovolt peak.

2. A method as set forth in claim 1, wherein said anode includes a single rotating target upon which said first plurality of electrons and said second plurality of electrons impinge.

3. A method as set forth in claim 2, wherein steps (c) and (d) are performed in an alternating manner.

4. A method as set forth in claim 1, wherein said anode includes a first rotating target upon which said first plurality of electrons impinge, and said anode includes a second rotating target upon which said second plurality of electrons impinge.

5. A method as set forth in claim 4, wherein steps (c) and (d) are performed in an alternating manner.

6. A method as set forth in claim 1, wherein said filter device includes a first filter and a second filter that respectively have different energy-absorbing characteristics.

7. A method as set forth in claim 1, wherein said alternating pulse composite x-ray beam is formed so as to have a plurality of x-ray quantity-versus-energy peaks.

8. A method as set forth in claim 1, wherein said detector includes at least one array of multiple detector elements for generating said x-ray signals according to the energy intensity of said composite x-ray beam.

9. A method as set forth in claim 1, wherein said x-ray image is generated so as to have differentiable energy-density characteristics on a display.

10. A method of scanning a patient, said method comprising the steps of:

(a) establishing a first electron-accelerating voltage potential between a first cathode and an anode;

(b) establishing a second electron-accelerating voltage potential between a second cathode and said anode;

(c) emitting a first plurality of electrons from said first cathode and toward said anode so that said first plurality of electrons impinge on said anode and thereby generate a first x-ray beam;

(d) emitting a second plurality of electrons from said second cathode and toward said anode so that said second plurality of electrons impinge on said anode and thereby generate a second x-ray beam;

(e) directing said first x-ray beam and said second x-ray beam through a filter device so as to form a composite x-ray beam;

(f) directing said composite x-ray beam through said patient and thereafter receiving said composite x-ray beam with a detector so as to accordingly generate x-ray signals; and

(g) generating an x-ray image in response to said x-ray signals;

wherein said first electron-accelerating voltage potential has a characteristic first kilovolt peak, said second electron-accelerating voltage potential has a characteristic second kilovolt peak, and said second kilovolt peak is different from said first kilovolt peak;

wherein said anode includes a first rotating target upon which said first plurality of electrons impinge, and said anode includes a second rotating target upon which said second plurality of electrons impinge; and

wherein steps (c) and (d) are performed simultaneously.

11. A method of scanning a patient, said method comprising the steps of:

(a) establishing a first electron-accelerating voltage potential between a first cathode and an anode;

(b) establishing a second electron-accelerating voltage potential between a second cathode and said anode;

(c) emitting a first plurality of electrons from said first cathode and toward said anode so that said first plurality of electrons impinge on said anode and thereby generate a first x-ray beam;

(d) emitting a second plurality of electrons from said second cathode and toward said anode so that said second plurality of electrons impinge on said anode and thereby generate a second x-ray beam;

(e) directing said first x-ray beam and said second x-ray beam in an alternating fashion through a filter device so as to form an alternating pulse composite x-ray beam having a plurality of x-ray quantity-versus-energy peaks;

(f) directing said alternating pulse composite x-ray beam through said patient and thereafter receiving said alternating pulse composite x-ray beam with an energy-differentiating detector so as to accordingly generate x-ray signals according to the energy intensity of said alternating pulse composite x-ray beam; and

(g) generating an x-ray image in response to said x-ray signals so that said x-ray image has differentiable energy-density characteristics on a display;

wherein said first electron-accelerating voltage potential has a characteristic first kilovolt peak, said second electron-accelerating voltage potential has a characteristic second kilovolt peak, and said second kilovolt peak is different from said first kilovolt peak.

12. A method as set forth in claim 11, wherein said anode includes a single rotating target upon which said first plurality of electrons and said second plurality of electrons impinge, and steps (c) and (d) are performed in an alternating manner.

13. A method of scanning a patient, said method comprising the steps of:

(a) establishing a first electron-accelerating voltage potential between a first cathode and an anode;

(b) establishing a second electron-accelerating voltage potential between a second cathode and said anode;

(c) emitting a first plurality of electrons from said first cathode and toward said anode so that said first plurality of electrons impinge on said anode and thereby generate a first x-ray beam;

(d) emitting a second plurality of electrons from said second cathode and toward said anode so that said second plurality of electrons impinge on said anode and thereby generate a second x-ray beam;

(e) directing said first x-ray beam and said second x-ray beam through a filter device so as to form a composite x-ray beam having a plurality of x-ray quantity-versus-energy peaks;

(f) directing said composite x-ray beam through said patient and thereafter receiving said composite x-ray beam with an energy-differentiating detector so as to accordingly generate x-ray signals according to the energy intensity of said composite x-ray beam; and

(g) generating an x-ray image in response to said x-ray signals so that said x-ray image has differentiable energy-density characteristics on a display;

wherein said first electron-accelerating voltage potential has a characteristic first kilovolt peak, said second electron-accelerating voltage potential has a characteristic second kilovolt peak, and said second kilovolt peak is different from said first kilovolt peak;

wherein said anode includes a first rotating target upon which said first plurality of electrons impinge, said anode includes a second rotating target upon which said second plurality of electrons impinge, and steps (c) and (d) are performed simultaneously.

14. A method of scanning a patient, said method comprising the steps of:

emitting a first plurality of electrons from a first cathode and toward an anode so that said first plurality of electrons impinge on said anode and thereby generate a first x-ray beam;

emitting a second plurality of electrons from a second cathode and toward said anode so that said second plurality of electrons impinge on said anode and thereby generate a second x-ray beam;

directing said first x-ray beam and said second x-ray beam alternately through a filter device so as to form an x-ray beam with alternating characteristics;

directing said alternating characteristic x-ray beam through said patient and thereafter receiving said alternating characteristic x-ray beam with a detector so as to accordingly generate x-ray signals; and

generating an x-ray image in response to said x-ray signals;

wherein said filter device includes a first filter and a second filter that respectively have different energy-absorbing characteristics; and

wherein said filter device is operable to rotatably interchange the respective positions of said first filter and said second filter as said first x-ray beam and said second x-ray beam are respectively directed through said filter device.

15. A method of scanning a patient, said method comprising the steps of:

emitting a first plurality of electrons from a first cathode and toward an anode so that said first plurality of electrons impinge on said anode and thereby generate a first x-ray beam;

emitting a second plurality of electrons from a second cathode and toward said anode so that said second plurality of electrons impinge on said anode and thereby generate a second x-ray beam;

directing said first x-ray beam and said second x-ray beam in an alternating fashion through a filter device so as to form a alternating pulse composite x-ray beam having a plurality of x-ray quantity-versus-energy peaks;

directing said alternating pulse composite x-ray beam through said patient and thereafter receiving said alternating pulse composite x-ray beam with an energy-differentiating detector so as to accordingly generate x-ray signals according to the energy intensity of said alternating pulse composite x-ray beam; and

generating an x-ray image in response to said x-ray signals so that said x-ray image has differentiable energy-density characteristics on a display;

wherein said filter device includes a first filter and a second filter that respectively have different energy-absorbing characteristics, and said filter device is operable to rotatably interchange the respective positions of said first filter and said second filter as said first x-ray beam and said second x-ray beam are respectively directed through said filter device.

16. A system for scanning a patient, said system comprising:

a first cathode operable to emit a first plurality of electrons;

a second cathode operable to emit a second plurality of electrons;

an anode for thereon impinging said first plurality of electrons and said second plurality of electrons in an alternating fashion so as to respectively generate a first x-ray beam alternating with a second x-ray beam;

a filter device operable to filter said first x-ray beam and said second x-ray beam so as to form an alternating pulse composite x-ray beam;

a detector operable to receive said composite x-ray beam after being directed through said patient and accordingly generate x-ray signals;

a display operable to generate an x-ray image in response to said x-ray signals; and

at least one controller electrically coupled to said first cathode, said second cathode, said anode, said filter device, said detector, and said display;

wherein said filter device includes a first filter and a second filter that respectively have different energy-absorbing characteristics; and

wherein said controller is operable to control said filter device so as to rotatably interchange the respective positions of said first filter and said second filter as said first x-ray beam and said second x-ray beam are respectively directed through said filter device.

17. A system as set forth in claim 16, wherein said anode is rotatable.

18. A system as set forth in claim 16, wherein said anode includes a single rotatable target upon which said first plurality of electrons and said second plurality of electrons can impinge.

19. A system as set forth in claim 16, wherein said anode includes a first rotatable target upon which said first plurality of electrons can impinge, and said anode includes a second rotatable target upon which said second plurality of electrons can impinge.

20. A system as set forth in claim 16, wherein said detector includes at least one array of multiple detector elements for generating said x-ray signals according to the energy intensity of said composite x-ray beam.