Grating for phase-contrast imaging

Patent metadata

Field	Value
Publication number	US-9805834-B2
Application number	US-201013266692-A
Country	US
Kind code	B2
Filing date	May 17, 2010
Priority date	May 19, 2009
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

The invention relates to gratings for X-ray differential phase-contrast imaging, a focus detector arrangement and X-ray system for generating phase-contrast images of an object and a method of phase-contrast imaging for examining an object of interest. In order to provide gratings with a high aspect ratio but low costs, a grating for X-ray differential phase-contrast imaging is proposed, comprising a first sub-grating ( 112 ), and at least a second sub-grating ( 114; 116; 118 ), wherein the sub-gratings each comprise a body structure ( 120 ) with bars ( 122 ) and gaps ( 124 ) being arranged periodically with a pitch (a), wherein the sub-gratings ( 112; 114; 116; 118 ) are arranged consecutively in the direction of the X-ray beam, and wherein the sub-gratings ( 112; 114; 116; 118 ) are positioned displaced to each other perpendicularly to the X-ray beam.

First claim

The invention claimed is:

1. A grating for X-ray differential phase-contrast imaging, comprising:
a first sub-grating; and
at least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,
said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, said grating being configured as one of a phase grating, an analyzer grating, and an absorption grating.

2. The grating of claim 1 , projections of said sub-gratings resulting in an effective grating with a smaller effective pitch than the pitches of said sub-gratings.

3. The grating of claim 1 , said sub-gratings having the same pitch.

4. The grating of claim 3 , wherein the displacement of one of said sub-gratings from another one of said sub-gratings is an offset amounting to a fraction of half the pitch.

5. The grating of claim 1 , wherein the sub-gratings have an equal bars/gap ratio.

6. A grating for X-ray differential phase-contrast imaging, comprising:
a first sub-grating; and
at least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,
said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, wherein the pitch of one of said sub-gratings is a multiple of the pitch of another one of said sub-gratings.

7. A grating for X-ray differential phase-contrast imaging, comprising:
a first sub-grating; and
at least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,
said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, wherein said sub-gratings each has a height that creates a π-phase shift at a design wavelength.

8. A grating for X-ray differential phase-contrast imaging, comprising:
a first sub-grating; and
at least a second sub-grating, the sub-gratings each comprising a body structure with bars, and gaps, arranged periodically with a pitch,
said sub-gratings being arranged consecutively for receiving an X-ray beam and being positioned laterally displaced from each other, said sub-gratings being arranged on a single wafer.

9. A detector arrangement of an X-ray system for generating phase-contrast images of an object, said arrangement comprising:
an X-ray source;
a source grating;
a phase grating;
an analyzer grating; and
a detector,
wherein the X-ray source is adapted to generate polychromatic spectrum of X-rays; and
wherein at least one of the phase and analyzer gratings is a grating according to claim 1 .

10. An X-ray system for generating phase-contrast data of an object, said system comprising the detector arrangement of claim 9 .

11. A method of phase-contrast imaging for examining an object of interest, comprising:
applying X-ray radiation beams of an X-ray source to a source-grating splitting the beams;
applying the splitted beams to a phase grating recombining the splitted beams in an analyzer plane;
applying the recombined beams to an analyzer grating; and
recording raw image data with a sensor while stepping the analyzer grating transversely over one period of the analyzer grating,
wherein at least one of the phase and analyzer gratings is a grating according to claim 1 .

12. A non-transitory computer-readable medium embodying a computer program for examination of an object of interest via phase-contrast imaging, said program having instructions executable by a processor of an X-ray system for causing the system to carry out a plurality of acts, among said plurality there being the acts of:
applying ( 52 ) X-ray radiation beams of an X-ray source to a source-grating splitting the beams;
applying the splitted beams to a phase grating recombining the splitted beams in an analyzer plane;
applying the recombined beams to an analyzer grating; and
recording raw image data with a sensor while stepping the analyzer grating transversely over one period of the analyzer grating;
wherein at least one of the phase and analyzer gratings is a grating according to claim 1 .

13. The grating of claim 1 , said sub-gratings having respective front surfaces and being arranged so that said surfaces are disposed normal to said beam and face in a direction of arrival of said beam.

14. The grating of claim 1 , a given sub-grating from among said sub-gratings comprising silicon, and an additional gold layer covering said bars, and said gaps, of the body structure of said given sub-grating.

15. The grating of claim 2 , said effective grating being defined by sidewalls in a propagation direction of an X-ray beam, in which direction said sub-gratings face.

16. The grating of claim 15 , a given sub-grating from among said sub-gratings comprising silicon, and an additional gold layer covering said bars, and said gaps, of the body structure of said given sub-grating.

17. The computer readable medium of claim 12 , among said plurality of acts there being a further act of computing the recorded raw image data into display data.

18. The grating of claim 1 , said sub-gratings facing in a same direction.

19. The grating of claim 18 , the displacement being normal to said direction.

20. The grating of claim 18 , the respective displacements of each of said sub-gratings from the other one or more of said sub-gratings being normal to said direction.

Assignees

• Koehler Thomas
• Roessl Ewald
• Koninklijke Philips Nv

Inventors

• Koehler Thomas
• Roessl Ewald

Classifications

• G21K1/06 Primary

  using diffraction, refraction or reflection, e.g. monochromators (G21K1/10, G21K7/00 take precedence) · CPC title

• G21K2207/005

  Methods and devices obtaining contrast from non-absorbing interaction of the radiation with matter, e.g. phase contrast · CPC title