FOCAL SPOT SENSING DEVICE AND METHOD IN AN IMAGING SYSTEM

• US 20050129175A1
• Filed: 12/12/2003
• Published: 06/16/2005
• Est. Priority Date: 12/12/2003
• 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: Shen, Bing, Toth, Thomas Louis, Hoffman, David Michael
• Granted Patent: US 7,286,639 B2
• Time in Patent Office: Days
• US Class Current: 378/62
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4021 involving movement of the focal spot
• CPC Class Codes: A61B 6/583 using calibration phantoms

Abstract

A focal spot sensing device includes: a housing that resists x-ray beams; an opening disposed in a wall of the housing that allows an x-ray beam to enter the housing; and a sensor device disposed in the housing that interprets a position of the x-ray beam for calculating a position of a focal spot. An imaging system includes: an x-ray source that produces an x-ray beam and has a focal spot; a detector array that receives the x-ray beam and includes a focal spot sensing device, the focal spot sensing device includes: a housing that resists x-ray beams; an opening disposed in a wall of the housing that allows the x-ray beam to enter the housing; and a sensor device disposed in the housing that interprets a position of the x-ray beam for calculating a position of the focal spot. A method for sensing a focal spot, the method includes: receiving an x-ray beam into an opening of a focal spot sensing device; interpreting a position of the x-ray beam; and calculating or measuring a position of a focal spot.

Claims

1. A focal spot sensing device comprising:

a housing that resists x-ray beams;

an opening disposed in a wall of the housing that allows an x-ray beam to enter the housing; and

a sensor device disposed in the housing that interprets a position of the x-ray beam for calculating a position of a focal spot.

2. The device of claim 1, wherein the opening is sized so that the x-ray beam strikes the sensor device.

3. The device of claim 1, wherein the opening is sized such that the x-ray beam at a surface of the sensor device is less than a total sensitive area of the sensor device.

4. The device of claim 1, wherein the sensor device includes at least two detector elements arranged next to each other.

5. The device of claim 4, wherein the at least two detector elements include a scintillator and a photodiode.

6. The device of claim 1, wherein the sensor device includes a fluorescent screen, which faces the opening so that the x-ray beam strikes the fluorescent screen, and a position sensitive photodiode that is arranged between the fluorescent screen and a back wall of the housing.

7. The device of claim 6, wherein the opening is dimensioned to be approximately a pinhole.

8. The device of claim 6, wherein the fluorescent screen is optically coupled to the position sensitive photodiode.

9. The device of claim 8, wherein the fluorescent screen is optically coupled to the position sensitive photodiode by a transparent epoxy layer.

10. The device of claim 1, further comprising a control mechanism in electronic communication with the sensor device.

11. The device of claim 10, wherein the control mechanism calculates the focal spot movement and compensates for detector response error induced by focal spot movement.

12. A focal spot sensing device comprising:

a housing that resists x-ray beams;

an opening disposed in the housing that allows an x-ray beam to enter the housing; and

means for calculating a position of a focal spot.

13. The device of claim 12, wherein the opening is sized so that the x-ray beam strikes the means for calculating.

14. The device of claim 12, wherein the opening is sized such that the x-ray beam at a surface of the means for calculating is less than a total sensitive area of the means for calculating.

15. The device of claim 12, wherein the means for calculating includes at least two detector elements arranged next to each other and the opening is sized so that the x-ray beam strikes the at least two detector elements.

16. The device of claim 12, wherein the means for calculating includes a fluorescent screen, which faces the opening so that the x-ray beam strikes the fluorescent screen, and a position sensitive photodiode that is arranged between the fluorescent screen and a back wall of the housing;

and the opening is dimensioned to be approximately a pinhole.

17. The device of claim 16, wherein the fluorescent screen is optically coupled to the position sensitive photodiode by a transparent epoxy layer.

18. The device of claim 12, further comprising a control mechanism in electronic communication with the means for calculating a position of a focal spot.

19. The device of claim 18, wherein the control mechanism calculates the focal spot movement and compensates for detector response error induced by focal spot movement.

20. An imaging system comprising:

an x-ray source that produces an x-ray beam and has a focal spot;

a detector array that receives the x-ray beam and includes a focal spot sensing device, the focal spot sensing device includes;

a housing that resists x-ray beams;

an opening disposed in a wall of the housing that allows the x-ray beam to enter the housing; and

a sensor device disposed in the housing that interprets a position of the x-ray beam for calculating a position of the focal spot.

21. The device of claim 20, wherein the opening is sized so that the x-ray beam strikes the sensor device.

22. The device of claim 20, wherein the opening is sized such that the x-ray beam at a surface of the sensor device is less than a total sensitive area of the sensor device.

23. The device of claim 20, wherein the sensor device includes at least two detector elements arranged next to each other and the opening is sized so that the x-ray beam strikes the at least two detector elements.

24. The device of claim 20, wherein the sensor device includes a fluorescent screen, which faces the opening so that the x-ray beam strikes the fluorescent screen, and a position sensitive photodiode that is arranged between the fluorescent screen and a back wall of the housing;

and the opening is dimensioned to be approximately a pinhole.

25. The device of claim 24, wherein the fluorescent screen is optically coupled to the position sensitive photodiode by a transparent epoxy layer.

26. The system of claim 20, further comprising a control mechanism in electronic communication with the detector array and the x-ray source.

27. A method for sensing a focal spot, the method comprising:

receiving an x-ray beam into an opening of a focal spot sensing device;

interpreting a position of the x-ray beam; and

calculating a position of a focal spot.

28. The method of claim 27, further comprising calibrating a CT system detector response to the position of a focal spot.

29. The method of claim 27, further comprising receiving the x-ray beam at a sensor device disposed in the focal spot sensing device, the sensor device includes at least two detector elements arranged next to each other.

30. The method of claim 27, further comprising receiving the x-ray beam at a sensor device disposed in the focal spot sensing device, the sensor device includes a fluorescent screen, which faces the opening so that the x-ray beam strikes the fluorescent screen, and a position sensitive photodiode that is arranged between the fluorescent screen and a back wall of the focal spot sensing device.