FULL FIELD DIGITAL TOMOSYNTHESIS METHOD AND APPARATUS

• US 20040109529A1
• Filed: 12/10/2002
• Published: 06/10/2004
• Est. Priority Date: 12/10/2002
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Eberhard, Jeffrey Wayne, Claus, Bernhard Erich Hermann, Muller, Serge Louis Wilfrid, Landberg, Cynthia Elizabeth, Morrow, James George, Delmas, Yann, Wirth, Reinhold Franz
• Granted Patent: US 7,110,490 B2
• Time in Patent Office: Days
• US Class Current: 378/23
• CPC Class Codes: A61B 6/025 Tomosynthesis
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4014 arranged in multiple source-detector units
• CPC Class Codes: A61B 6/4028 resulting in acquisition of views from substantially different positions, e.g. EBCT
• CPC Class Codes: A61B 6/4266 characterised by using a plurality of detector units A61B6/4014 takes precedence
• CPC Class Codes: A61B 6/4429 related to the mounting of source units and detector units
• CPC Class Codes: A61B 6/502 for diagnosis of breast, i.e. mammography

Abstract

A tomosynthesis system for forming a three dimensional image of an object is provided. The system includes an X-ray source adapted to irradiate the object with a beam of X-rays from a plurality of positions in a sector, an X-ray detector positioned relative to the X-ray source to detect X-rays transmitted through the object and a processor which is adapted to generate a three dimensional image of the object based on X-rays detected by the detector. The detector is adapted to move relative to the object and/or the X-ray source is adapted to irradiate the object with the beam of X-rays such that the beam of X-rays follows in a non arc shaped path and/or a center of the beam of X-rays impinges substantially on the same location on the detector from different X-ray source positions in the sector.

Claims

1. A tomosynthesis system for forming a three dimensional image of an object, comprising:

an X-ray source adapted to irradiate the object with a beam of X-rays from a plurality of positions along a path in a sector;

an X-ray detector positioned relative to the X-ray source to detect X-rays transmitted through the object; and

a processor which is adapted to generate a three dimensional image of the object based on X-rays detected by the detector;

wherein;

the detector is adapted to move relative to the object;

or

the X-ray source is adapted to irradiate the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path;

or

a center of the beam of X-rays impinges substantially on the same location on the detector from different X-ray source positions in the sector.

2. The system of claim 1, wherein the system comprises a mammography tomosynthesis system and the object comprises a human breast.

3. The system of claim 2, wherein the detector is adapted to move relative to the object.

5. The system of claim 3, wherein:

the X-ray source is adapted to rotate in an arc shaped path in a first direction relative to the object; and

the detector is adapted to move in a path in a plane in a second direction opposite to the first direction during rotation of the X-ray source.

6. The system of claim 3, wherein:

the X-ray source is adapted to rotate along the path in the sector in a first angular direction relative to the object, such that the focal spot of the X-ray beam moves in the first angular direction; and

the detector is adapted to rotate in the direction different from the first angular direction.

7. The system of claim 3, wherein:

the X-ray source is adapted to rotate in an arc shaped path in a first angular direction relative to the object; and

the detector is adapted to move in an arc shaped path in a second angular direction opposite to the first direction.

8. The system of claim 2, wherein the X-ray source is adapted to irradiate the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path relative to the detector.

9. The system of claim 8, wherein the X-ray source is adapted to rotate in a first angular direction along the path and to move in a second direction substantially along a second radial direction.

10. The system of claim 8, wherein the X-ray source is adapted to rotate in a first angular direction and an electron beam focal spot is adapted to change position on an X-ray target in the X-ray source to move the X-ray beam focal spot in a second direction substantially along the second radial direction.

11. The system of claim 8, wherein the X-ray source is adapted to rotate along the path in a first angular direction and move in at least one of a third and fourth directions outside a plane of rotation of the X-ray source.

12. The system of claim 8, wherein the X-ray source is adapted to rotate along the path in a first angular direction and an electron beam focal spot is adapted to change position on an X-ray target in the X-ray source to move the X-ray beam focal spot in at least one of a third and fourth directions outside a plane of rotation of the X-ray source.

13. The system of claim 8, wherein the X-ray source is adapted to rotate along the path in a first angular direction and an X-ray lens is adapted move the X-ray beam focal spot in at least one of a third and fourth directions outside a plane of rotation of the X-ray source.

14. The system of claim 2, wherein the X-ray source is adapted to rotate along the path in a first angular direction and to turn in a fifth direction such that the center of the X-ray beam impinges substantially on the same location on the detector from different X-ray source positions in the sector.

15. The system of claim 2, wherein the X-ray source is adapted to rotate along the path in a first angular direction and a collimator changes a position of the X-ray beam to turn the X-ray beam in a fifth direction such that the center of the X-ray beam impinges substantially on the same location on the detector from different X-ray source positions in the sector.

16. The system of claim 2, wherein:

the detector is adapted to move relative to the object; and

the X-ray source is adapted to irradiate the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path relative to the detector.

4. The system of 3, further comprising:

a detector housing; and

a piezoelectric actuator adapted to move the detector in the detector housing.

17. A tomosynthesis system for forming a three dimensional image of an object, comprising:

a first means for irradiating the object with a beam of X-rays from a plurality of positions along a path in a sector, a second means for detecting X-rays transmitted through the object; and

a third means for generating a three dimensional image of the object based on X-rays detected by the second means;

wherein;

the second means is a means for detecting X-rays transmitted through the object and also for moving relative to the object;

or

the first means is a means for irradiating the object with the beam of X-rays such that a focal spot of the beam of X-rays follows a non arc shaped path relative to the object;

or

the first means is a means for irradiating the object with the beam of X-rays such that a center of the beam of X-rays impinges substantially on the same location on the second means from different first means positions in the sector.

18. The system of claim 17, wherein the system comprises a mammography tomosynthesis system and the object comprises a human breast.

19. The system of claim 18, wherein the second means is a means for detecting X-rays transmitted through the object and also for moving relative to the object.

21. The system of claim 19, wherein:

the first means is a means for irradiating the object with the beam of X-rays and also for rotating in an arc shaped path in a first direction relative to the object; and

the second means is a means for detecting X-rays transmitted through the object and also for moving in a path in a second direction opposite to the first direction during rotation of the first means.

22. The system of claim 19, wherein:

the first means is a means for irradiating the object with the beam of X-rays and also for rotating in an arc shaped path in a first direction relative to the object; and

the second means is a means for detecting X-rays transmitted through the object and also for moving in an arc shaped path in a second direction opposite to the first direction.

23. The system of claim 19, wherein:

the first means is a means for irradiating the object with the beam of X-rays and also for rotating in the sector in a first direction relative to the object and for moving the X-ray beam focal spot in a y-direction; and

the second means is a means for detecting X-rays transmitted through the object and also for rotating in a direction different from the first direction.

24. The system of claim 18, wherein the first means is a means for irradiating the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path relative to the object.

25. The system of claim 24, wherein the first means is a means for irradiating the object with the beam of X-rays and also for rotating in a first angular direction and for moving the focal spot of the X-ray beam in a second direction substantially along a second radial direction.

26. The system of claim 24, wherein the first means is a means for irradiating the object with the beam of X-rays and also for rotating in a first angular direction for moving the focal spot of the X-ray beam in at least one of a third and fourth directions outside a plane of rotation of the first means.

27. The system of claim 18, wherein the first means is a means for irradiating the object with the beam of X-rays and also for rotating in the first angular direction and for directing a center of the X-ray beam to impinge substantially on the same location on the second means from different first means positions in the sector.

28. The system of claim 18, wherein:

the second means is a means for detecting X-rays transmitted through the object and also for moving relative to the object; and

the first means is a means for irradiating the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path relative to the object.

20. The system of 19, further comprising:

an actuator adapted to move the second means, wherein the second means comprises a detector; and

at least one of a movable arm and combination of a rail and a motor which is adapted to move the first means, wherein the first means comprises an X-ray source.

29. A tomosynthesis method of forming a three dimensional image of an object, comprising:

(a) acquiring a set of tomosynthesis projections, comprising moving an X-ray source along a path through a sector;

irradiating the object with a beam of X-rays from the X-ray source at a plurality of positions in the sector; and

detecting X-rays transmitted through the object with a detector; and

(b) generating a three dimensional image of the object based on the detected X-rays;

wherein;

the detector moves relative to the object during the acquisition of a set of tomosynthesis projections;

or

the X-ray source irradiates the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path;

or

a center of the beam of X-rays impinges substantially on the same location on the detector from different X-ray source positions in the sector.

30. The method of claim 29, wherein the method comprises a mammography tomosynthesis method and the object comprises a human breast.

31. The method of claim 30, wherein the detector moves relative to the object during the acquisition of a set of tomosynthesis projections.

32. The method of claim 31, wherein:

the X-ray source rotates in an arc shaped path in a first direction relative to the object and periodically emits a beam of X-rays at given positions on the arc shaped path; and

the detector moves in a path in a plane in a second direction opposite to the first direction while the X-ray source rotates in the first direction.

33. The method of claim 32, wherein the detector moves in the second direction while the X-ray source emits the beam of X-rays and the X-ray source moves in the first direction.

34. The method of claim 33, wherein the detector moves in the second direction while the X-ray source does not emit the beam of X-rays and the X-ray source moves in the first direction.

35. The method of claim 32, wherein the detector moves along the path in the second direction while the X-ray source does not emit the beam of X-rays and the X-ray source moves in the first direction.

36. The method of claim 31, wherein:

the X-ray source rotates in an arc shaped path in a first direction relative to the object and periodically emits a beam of X-rays at positions on the arc shaped path; and

the detector moves in an arc shaped path in a second direction opposite to the first direction while the X-ray source rotates in the first direction.

37. The method of claim 31, wherein:

the X-ray source rotates along the path in the sector in a first angular direction relative to the object and periodically emits a beam of X-rays;

the X-ray source moves the X-ray beam focal spot in a y-direction; and

the detector rotates in a direction different from the first direction.

38. The method of claim 30, wherein the X-ray source irradiates the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path relative to the object.

39. The method of claim 38, wherein the X-ray source rotates along the path in a first angular direction and the focal spot of the X-ray beam moves in a second direction substantially along a second radial direction.

40. The method of claim 38, wherein the X-ray source rotates along the path in a first angular direction and the focal spot of the X-ray beam moves in at least one of third and fourth directions outside a plane of rotation of the X-ray source.

41. The method of claim 30, wherein the X-ray source rotates along the path in a first angular direction and a center of the X-ray beam impinges substantially on the same location on the detector from different X-ray source positions along a rotational path of the X-ray source.

42. The method of claim 30, wherein, the detector moves relative to the object during the acquisition of a set of tomosynthesis projections;

and

the X-ray source irradiates the object with the beam of X-rays such that the focal spot of the beam of X-rays follows a non arc shaped path relative to the object.

43. A tomosynthesis system for forming a three dimensional image of an object, comprising:

an X-ray source adapted to periodically irradiate the object with a beam of X-rays, wherein the X-ray source is adapted to emit the beam of X-rays while moving in a first direction along a path in a sector;

an X-ray detector positioned relative to the X-ray source to detect X-rays transmitted through the object, wherein the detector is adapted to move in a second direction opposite to the first direction while the X-ray source moves in the first direction and the X-ray source emits the beam of X-rays; and

a processor which is adapted to generate a three dimensional image of the object based on X-rays detected by the detector.

44. The system of claim 43, wherein:

the X-ray source is adapted to rotate in an arc shaped path and to periodically emit the beam of X-rays from a plurality of positions along the arc shaped path; and

the X-ray source is adapted to rotate at a first speed while the X-ray source emits the beam of X-rays and to rotate at a second speed higher than the first speed while the X-ray source does not emit the beam of X-rays.

45. The system of claim 44, wherein:

the detector is adapted to move in the second direction to minimize maximum image blurring by at least 50% compared to image blurring if the detector does not move; and

the detector is adapted to move in the first direction while the X-ray source does not emit the beam of X-rays.

46. A tomosynthesis method of forming a three dimensional image of an object, comprising:

rotating an X-ray source in a first direction in a path through a sector;

emitting a beam of X-rays from the X-ray source while the X-ray source is moving along the path in the first direction;

periodically irradiating the object with the X-ray beam;

moving a detector in a second direction opposite to the first direction while the X-ray source emits the X-ray beam and the X-ray source moves in the first direction;

detecting X-rays transmitted through the object with the detector; and

generating a three dimensional image of the object based on the detected X-rays.

47. The method of claim 46, wherein:

rotating an X-ray source in a first direction along the path through a sector comprises rotating the X-ray source in an arc shaped path at a first speed while the X-ray source emits the beam of X-rays and at a second speed higher than the first speed while the X-ray source does not emit the beam of X-rays.

48. The system of claim 47, wherein:

the detector moves in the second direction to minimize maximum image blurring by at least 50% compared to image blurring if the detector does not move; and

the detector moves in the first direction while the X-ray source does not emit the beam of X-rays.

49. The method of claim 48, wherein:

the X-ray source rotates through a length of about 10 to 750 microns in the first direction along the path while the X-ray source emits one X-ray beam;

the detector moves about 5 to 60 micros in the second direction while the X-ray source emits one X-ray beam; and

beam magnification is about 1.05 to 8.

50. A tomosynthesis system for forming a three dimensional image of an object, comprising:

at least two X-ray sources adapted to irradiate the object with beams of X-rays from a plurality of positions along a path in a sector;

an X-ray detector positioned relative to the at least two X-ray sources to detect X-rays transmitted through the object; and

a processor which is adapted to generate a three dimensional image of the object based on X-rays detected by the detector.

51. The system of claim 50, wherein the at least two X-ray sources are adapted to rotate in an arc shaped path in respective at least two parallel planes and a first X-ray source is offset from a second X-ray source in a direction perpendicular to the parallel planes.

52. The system of claim 51, wherein the first X-ray source is further offset from the second X-ray source in the first direction during rotation of the first and second X-ray sources in the arc shaped path.

53. The system of claim 50, wherein the at least two X-ray sources comprise at least four stationary X-ray sources which are adapted to sequentially irradiate the object with the X-ray beams.