X-ray imaging apparatus and X-ray imaging method

• US 8,588,366 B2
• Filed: 10/19/2009
• Issued: 11/19/2013
• Est. Priority Date: 10/24/2008
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Mukaide, Taihei, Takada, Kazuhiro, Fukuda, Kazunori, Watanabe, Masatoshi
• Primary Examiner(s): THOMAS, COURTNEY D
• Application Number:
  US13/060,739
• Publication Number:
  US 20110158389A1
• Time in Patent Office: 1,492 Days
• Field of Search: 378/62, 378/154
• US Class Current: 378/62
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/484 involving phase contrast X-ray 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: G01T 1/00 Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation G01T3/00, G01T5/00 take precedence
• CPC Class Codes: G21K 2207/005 Methods and devices obtaining contrast from non-absorbing interaction of the radiation with matter, e.g. phase contrast

Abstract

An X-ray imaging apparatus for obtaining information on a phase shift of an X-ray caused by an object comprises: an splitting element for splitting spatially an X-ray emitted from an X-ray generator unit into X-ray beams; an attenuator unit having an arrangement of attenuating elements for receiving the X-ray beams split by the splitting element; and an intensity detector unit for detecting intensities of X-ray beams attenuated by the attenuator unit; and the attenuating element changing continuously the transmission amount of the X-ray depending on the X-ray incident position on the element.

Claims

1. An X-ray imaging apparatus for obtaining information on a phase shift of X-rays caused by an object, comprising:

a splitting element for splitting spatially X-rays emitted from an X-ray generator unit into X-ray beams;

an attenuator unit having an arrangement of attenuating elements for receiving the X-ray beams split by said splitting element; and

an intensity detector unit for detecting intensities of X-ray beams attenuated by said attenuator unit,

said attenuating element changing continuously the transmission amount of the X-rays depending on the X-ray incident position on said attenuating element.

2. The X-ray imaging apparatus according to claim 1, further comprising a calculation unit for calculating a differential phase contrast image or a phase contrast image of the object from the X-ray intensity information detected by said intensity detector unit.

3. The X-ray imaging apparatus according to claim 1, wherein said attenuating element has a thickness changing continuously in a direction perpendicular to incident X-rays.

4. The X-ray imaging apparatus according to claim 3, wherein said attenuating element is in a shape of a triangular prism.

5. The X-ray imaging apparatus according to claim 1, wherein said attenuating element has a density varying continuously in a direction perpendicular to the incident X-rays.

6. The X-ray imaging apparatus according to claim 1, wherein said attenuating element is in a shape which makes positive a second-order differential value of the optical path length in said attenuating element with respect to the X-ray incident position.

7. The X-ray imaging apparatus according to claim 1, further comprising a movement mechanism for moving synchronously said X-ray generator unit, said splitting element, said attenuator unit, and said intensity detector unit.

8. A method for X-ray imaging with an X-ray imaging apparatus, comprising the steps of:

splitting X-rays spatially; and

collecting information on an X-ray phase shift caused by an object, by use of an attenuator unit having an arrangement of attenuating elements, from the intensity of X-rays which have been transmitted through the attenuating elements,

the attenuating element changing continuously the transmission amount of the X-rays corresponding to the X-ray incident position in the attenuating element.

9. An X-ray imaging apparatus, comprising:

an X-ray generator unit for generating X-rays;

an attenuator unit having an arrangement of a plurality of attenuating elements having each an absorptive power gradient changing continuously the transmission amount of the X-rays in accordance with an intensity distribution of the X-rays which have been transmitted through an object; and

an X-ray intensity detector for detecting the intensity of the X-rays which have been attenuated by said attenuator unit.

10. A method for X-ray imaging with an X-ray imaging apparatus, which employs an attenuator unit having an arrangement of a plurality of attenuating elements having each an absorptive power gradient changing continuously the transmission amount of the X-rays in accordance with an intensity distribution of the X-rays which have been transmitted through an object to detect a change in intensity distribution of the X-rays that have passed through the attenuating element, said method comprising the steps of:

generating the X-rays; and

collecting information on an X-ray phase shift caused by the object.

11. An X-ray imaging apparatus comprising:

an attenuator unit having an arrangement of attenuating elements for receiving X-ray beams which have been transmitted through an object; and

an intensity detector unit for detecting intensities of X-ray beams attenuated by said attenuator unit,

wherein said intensity detector unit has a plurality of pixels, and

wherein said attenuating elements are configured such that transmission amounts of the X-ray beams change continuously or stepwise in accordance with incident positions of the X-ray beams.

12. The X-ray imaging apparatus according to claim 11, further comprising:

a splitting element for splitting spatially an X-ray emitted from an X-ray generator unit into the X-ray beams,

wherein said attenuating elements are configured to receive the X-ray beams split by said splitting element.

13. The X-ray imaging apparatus according to claim 12, wherein said attenuating elements are configured to receive the X-ray beams after the split X-ray beams have been transmitted through the object.

14. The X-ray imaging apparatus according to claim 11, further comprising a calculation unit for calculating a differential phase contrast image or a phase contrast image of the object from the X-ray intensity information detected by said intensity detector unit.

15. The X-ray imaging apparatus according to claim 11, wherein said attenuating elements have a thickness changing in a direction perpendicular to an incident X-ray.

16. The X-ray imaging apparatus according to claim 11, wherein said attenuating elements have a density varying in a direction perpendicular to the incident X-ray.

17. The X-ray imaging apparatus according to claim 11, wherein said attenuating elements each are in a shape which gives a positive d²t(x)/dx² value when the incident position of the X-ray is taken as x and an optical path length of the attenuating element is taken as t(x).

18. The X-ray imaging apparatus according to claim 11, further comprising a movement mechanism for moving said attenuator unit and said intensity detector unit synchronously.

19. An X-ray imaging method comprising:

detecting, by a detector unit which has an arrangement of pixels, an intensity of X-ray beams which have been transmitted through an attenuator unit having an arrangement of attenuating elements for receiving X-ray beams which have been transmitted through an object,

wherein the attenuator unit is configured such that transmission amount of the X-ray changes continuously or stepwise in accordance with an incident position of the X-ray.

20. The X-ray imaging method according to claim 19, further comprising

splitting an X-ray spatially,

wherein the attenuator unit is configured to receive split X-ray beams.