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WO2010150136A1 - Grating-based phase contrast x-ray imaging apparatus and methods - Google Patents

Grating-based phase contrast x-ray imaging apparatus and methods Download PDF

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Publication number
WO2010150136A1
WO2010150136A1 PCT/IB2010/052656 IB2010052656W WO2010150136A1 WO 2010150136 A1 WO2010150136 A1 WO 2010150136A1 IB 2010052656 W IB2010052656 W IB 2010052656W WO 2010150136 A1 WO2010150136 A1 WO 2010150136A1
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Prior art keywords
grating
ray
phase
anode
contrast
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PCT/IB2010/052656
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French (fr)
Inventor
Gereon Vogtmeier
Klaus J. Engel
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Koninklijke Philips Electronics N. V.
Philips Intellectual Property & Standards Gmbh
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Publication of WO2010150136A1 publication Critical patent/WO2010150136A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/046—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material using tomography, e.g. computed tomography [CT]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/02—Arrangements for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computed tomography [CT]
    • A61B6/032—Transmission computed tomography [CT]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/40—Arrangements for generating radiation specially adapted for radiation diagnosis
    • A61B6/4021—Arrangements for generating radiation specially adapted for radiation diagnosis involving movement of the focal spot
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4208—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4291—Arrangements for detecting radiation specially adapted for radiation diagnosis the detector being combined with a grid or grating
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/48—Diagnostic techniques
    • A61B6/484—Diagnostic techniques involving phase contrast X-ray imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N2223/00—Investigating materials by wave or particle radiation
    • G01N2223/40—Imaging
    • G01N2223/419—Imaging computed tomograph
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K2201/00—Arrangements for handling radiation or particles
    • G21K2201/06—Arrangements for handling radiation or particles using diffractive, refractive or reflecting elements
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K2207/00—Particular details of imaging devices or methods using ionizing electromagnetic radiation such as X-rays or gamma rays
    • G21K2207/005—Methods and devices obtaining contrast from non-absorbing interaction of the radiation with matter, e.g. phase contrast

Definitions

  • the invention relates to grating-based phase-contrast X-ray imaging apparatus and methods.
  • X-ray phase-contrast imaging or differential phase-contrast imaging (DPCI) visualizes the phase information of X-rays passing through a scanned object.
  • PCI X-ray phase-contrast imaging
  • DPCI differential phase-contrast imaging
  • phase-contrast imaging provides a tool for medical diagnostics and is increasingly used in other research areas such as environmental and materials science.
  • Major applications concern classes of samples such as biological tissues, polymers and fibre composites for which the use of conventional X-ray radiography is limited because these objects show only little absorption. Recording the X-ray phase-shift rather than only the absorption has the potential of substantially increased contrast.
  • Reference (1) discloses an apparatus and method to obtain phase-contrast X- ray images.
  • Reference (1) discloses a standard (i.e. incoherent) X-ray tube, a first beam splitter grating (diffraction grating), a second beam recombiner grating, a third analyzer grating (absorption grating) and an image detector.
  • a sample to be analyzed is arranged between the second beam recombiner grating and the third analyzer grating.
  • the arrangement including the analyzer grating and the image detector may be replaced be a special image detector having a strip-type sensitivity.
  • Reference (2) discloses an interferometer comprising a standard X-ray tube, a phase-grating, an analyzer grating, and an image detector.
  • a standard X-ray tube a phase-grating, an analyzer grating, and an image detector.
  • the X-ray tube X-ray source
  • some degree of spatial coherence at least in the direction perpendicular to the optical axis is required.
  • Reference (2) discloses three methods for extracting phase information from the signal intensity variation detected by the detector.
  • a first method involves obtaining a phase-contrast image by integration of the differential phase-contrast image obtained by the detector.
  • a second method involves Moire interferometry, by providing a small rotation angle between the phase-grating and the analyzer grating, such said these gratings are not perfectly parallel in respect of the lines.
  • a third method involves phase-stepping, by scanning one of the gratings along the transverse direction perpendicular to the grating lines over one period of the grating. Phase-stepping may be performed by moving the phase-grating or the analyser grating, by rotating the phase-grating and the analyzer grating, or by moving the X- ray source.
  • the X-ray source Due to the requirement of spatial coherency a line source can be used having a size of 0.1 mm along the direction perpendicular to the grating lines. Such source geometry is limited to relatively narrow line sources placed at large distances from the sample, resulting in a low X-ray flux density and therefore long exposure times. According to an improvement which provides a much higher flux density, the X-ray source consists of an arrow of N line sources oriented along the grating lines, wherein the width of each source line is sufficiently narrow to provide sufficient spatial coherence in the direction perpendicular to the grating lines; due to this measure, the flux density is increased by the factor N.
  • Such a source array may be obtained, for example, by generating an array of electron line foci on an anode surface, by using an anode surface which is structured; by generating a single line focus or spot focus that is scanned across the anode surface to produce, averaged over time, an array of lines; or by putting an array of slits, i.e. an amplitude grating, in front of a large X-ray source to generate an array of virtual line sources.
  • Reference (3) has as objects to expand the opportunities for data interpretation beyond the existing status, and to abolish the need for discontinuous movement of the object and intensity acquisition, when applying the phase- scanning approach.
  • the apparatus described in Reference (3) includes an amplitude grating (GO) in front of an X-ray source, a phase-grating (Gl), and an analyzer grating (G2).
  • GO amplitude grating
  • Gl phase-grating
  • G2 analyzer grating
  • grating G2 is scanned in the transverse direction.
  • a nested scan may be performed if each of sub-gratings G2 n in grating G2 are slightly shifted in their position perpendicular to the grating lines.
  • References (4) to (8) relate to further publications which are based on the research performed at the Paul Scherrer Institut in Switzerland.
  • Reference (9) discloses phase-contrast X-ray imaging system and methods with an application of a field emission X-ray source in phase-contrast imaging, and a multi- source arrangement to acquire phase and phase-contrast images.
  • a partially coherent X-ray beam propagates through an object, and from the image signals of a detector an attenuation-map and a phase-map are retrieved.
  • Intensity measurements are acquired by the detector at two different positions, either by moving a single detector, or by providing two detectors, one detector reading for determining attenuation, and the other detector reading for determining phase-contrast.
  • the X-ray source employed in Reference (9) may be constituted as a field emission device (FED) with a field emission cathode having an array of sharp points or tips.
  • the field emission cathode can be an electron gun made of metallic nanocrystal material with nanocrystals having a size of 1 to 2 nanometres. Since there is necessarily a trade-off between spatial coherence and high X-ray output, the X-ray output may be increased by providing a plurality of X-ray sources. A multi-step exposure process is performed in which only a portion of the X-ray sources generate X-rays during each of the steps of the process.
  • Each of the X-ray sources can be built with a very small focal spot size, resulting in point source operation.
  • the exposure area of each source can have a small size, thus reducing X-ray scatter, and providing improved image contrast and/or reduced object (i.e. patient) radiation.
  • the multi X-ray sources provide a sufficient photo flux.
  • each one of the two known approaches has limitations and/or disadvantages.
  • performing phase-stepping requires the movement of at least one member of the apparatus, whereas according to the second approach either a single detector has to be moved, or two detectors have to be provided.
  • the object of the invention is to provide an apparatus and method for an improved grating-based phase-contrast X-ray imaging.
  • the invention is indicated in the independent claims.
  • Advantageous embodiments of the invention are indicated in the dependent claims.
  • Fig. 1 shows an imaging apparatus according to the present invention
  • Fig. 2 shows details of the distributed X-ray source array of the apparatus according to the invention
  • Fig. 3 shows a prior art imaging system according to references [3-7] with three gratings
  • Fig. 4A shows an experimental DPCI setup, taken from references [3-7], with a source grating GO (for spatial beam coherence), a phase grating Gl
  • FIG. 4B shows cross sections of GO to G2 in Fig. 4A, GO and G2 being filled with gold
  • Fig. 5 shows an interference pattern created between Gl and G2, demonstrating the "self imaging" effect in characteristic distances di, d 2 and d 3 (Talbot effect); the relative position of the minima and maxima depends on the phase-shift of the wave front incident on Gl; in typical DPCI Setups, di is in the order of several cm; and Fig.
  • FIG. 3 A comparison of Fig. 3 (prior art) with an apparatus according to the present invention as depicted in Fig. 1 shows that according to the present invention a novel X-ray source is provided which does not require a source grating GO (Fig. 3) for providing spatial beam coherence.
  • a major advantage of the present invention is that none of the members of the imaging apparatus according to the invention needs to be moved.
  • movement devices have to be built according to very strict standards for providing the accuracy which is required for interferometers, such that movement devices are very complicated and therefore expensive.
  • an Y-ray source array including a plurality of distributed X-ray sources.
  • the X-ray source array allows a "virtual movement" of one or more small focal spots created by one ore more distributed X-ray sources.
  • a switching means is provided for switching the plurality of X-ray sources in a predetermined order.
  • One approach according to the invention is based on a common anode and a thermal electron source (a source for thermal electrons). At least one XY focussing and deflection unit is provided for scanning an electron beam emitted by the electron source on the anode as a target. In this manner, a scanning of the spatial modulated electron beam on the anode target is performed. This replaces the phase stepping of any grating.
  • Several "small" electron beams are focussed to an anode (which may be structured) to have different focus spot positions, each position corresponding to a slit of the grating GO in the prior art.
  • Another approach according to the invention is the realisation of several distributed small X-ray sources by field emitter devices like carbon nanotube based devices (CNT based X-ray source).
  • An advantage of this approach is the fast switching of the X-ray sources, instead of electron beam scanning according to the thermal electron emitter solution, such that no dynamical beam deflection units will be required.
  • the design of the emitters (e.g. CMT based) on a substrate, together with the single beam focussing units, has to be done in a way that resulting focus spot movement on the anode has the same effect in combination with the collimator geometry as the scanning movement of the grating GO (prior art) in front of the X-ray tube. In both ways a coherent pattern of single point sources that move along the x-direction is generated.
  • each focus spot would be chosen such that, if seen from the view point of the detector, the focus spot has a geometrical structure like a trench at the grating GO according to the prior art. This shaping would be supported by a relatively small anode angle, as an almost squared shape on the anode will turn into a small slit in the view projected to the detector. Distances and focussing have to be designed according to the geometry of focal spot and grating GO of a conventional system, to achieve a comparable coherent x-ray pattern. Details of the multi-pixel, multi-line array according to the present invention are shown in Fig. 2. An offset of 1/4 pixel may be provided for higher spatial resolution.
  • the invention provides an imaging apparatus with a switching X- ray source, wherein no mechanical scanning is required, but fast X-ray source switching is employed.
  • the distributed X-ray source array according to the invention generates coherent beams and replaces grating GO (and scanning by grating GO) with scanning/switching of the focal spot points.
  • DPCI differential phase contrast imaging
  • CT computed tomography

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Abstract

The invention relates to a grating-based phase-contrast X-ray imaging apparatus and corresponding method comprising an X-ray source array including a plurality of distributed X-ray sources which are switchable, a phase grating, an analyzer grating, and an image detector.

Description

GRATING-BASED PHASE CONTRAST X-RAY IMAGING APPARATUS AND METHODS
The invention relates to grating-based phase-contrast X-ray imaging apparatus and methods.
X-ray phase-contrast imaging (PCI) or differential phase-contrast imaging (DPCI) visualizes the phase information of X-rays passing through a scanned object. In addition to classical X-ray transmission imaging, (D)PCI determines not only the absorption properties of a scanned object along a projection line, but also the phase-shift of the transmitted X-rays, and thus provides valuable additional information useable for contrast enhancement, material composition or dose reduction. In particular, phase-contrast imaging provides a tool for medical diagnostics and is increasingly used in other research areas such as environmental and materials science. Major applications concern classes of samples such as biological tissues, polymers and fibre composites for which the use of conventional X-ray radiography is limited because these objects show only little absorption. Recording the X-ray phase-shift rather than only the absorption has the potential of substantially increased contrast.
Prior approaches for phase-contrast X-ray imaging used hard radiation provided by synchrotron radiation sources. Recently, a group at the Paul Scherrer Institut, Villingen, Switzerland, has shown a simple realization of PCI which can also be employed for medical imaging. The general outline of the field to which the present application relates is given in References (1) through (9) indicated below.
(I)WO 2004/071209 Al
(2)EP 1 731 099 Al (3)EP 1 879 020 Al
(4)F. Pfeiffer et al, Nature Physics 2, 258 (2006)
(5)F. Pfeiffer et al., Phys. Rev. Lett. 98, 108105 (2007)
(6)F. Pfeiffer et al., Europhysics News 37(5), 13 (2006)
(7)F. Pfeiffer et al., Phys. Rev. Lett. 94, 164801 (2005) (8)T. Weitkamp et al., Optics Express 13(16), 6296 (2005)
(9)US 7,412,026 Bl Reference (1) discloses an apparatus and method to obtain phase-contrast X- ray images. Reference (1) discloses a standard (i.e. incoherent) X-ray tube, a first beam splitter grating (diffraction grating), a second beam recombiner grating, a third analyzer grating (absorption grating) and an image detector. A sample to be analyzed is arranged between the second beam recombiner grating and the third analyzer grating. The arrangement including the analyzer grating and the image detector may be replaced be a special image detector having a strip-type sensitivity.
Reference (2) discloses an interferometer comprising a standard X-ray tube, a phase-grating, an analyzer grating, and an image detector. For the X-ray tube (X-ray source) some degree of spatial coherence at least in the direction perpendicular to the optical axis is required.
Reference (2) discloses three methods for extracting phase information from the signal intensity variation detected by the detector. A first method involves obtaining a phase-contrast image by integration of the differential phase-contrast image obtained by the detector. A second method involves Moire interferometry, by providing a small rotation angle between the phase-grating and the analyzer grating, such said these gratings are not perfectly parallel in respect of the lines. A third method involves phase-stepping, by scanning one of the gratings along the transverse direction perpendicular to the grating lines over one period of the grating. Phase-stepping may be performed by moving the phase-grating or the analyser grating, by rotating the phase-grating and the analyzer grating, or by moving the X- ray source. Due to the requirement of spatial coherency a line source can be used having a size of 0.1 mm along the direction perpendicular to the grating lines. Such source geometry is limited to relatively narrow line sources placed at large distances from the sample, resulting in a low X-ray flux density and therefore long exposure times. According to an improvement which provides a much higher flux density, the X-ray source consists of an arrow of N line sources oriented along the grating lines, wherein the width of each source line is sufficiently narrow to provide sufficient spatial coherence in the direction perpendicular to the grating lines; due to this measure, the flux density is increased by the factor N.
Such a source array may be obtained, for example, by generating an array of electron line foci on an anode surface, by using an anode surface which is structured; by generating a single line focus or spot focus that is scanned across the anode surface to produce, averaged over time, an array of lines; or by putting an array of slits, i.e. an amplitude grating, in front of a large X-ray source to generate an array of virtual line sources. As compared to Reference (2), Reference (3) has as objects to expand the opportunities for data interpretation beyond the existing status, and to abolish the need for discontinuous movement of the object and intensity acquisition, when applying the phase- scanning approach. The apparatus described in Reference (3) includes an amplitude grating (GO) in front of an X-ray source, a phase-grating (Gl), and an analyzer grating (G2). For the phase-stepping approach, grating G2 is scanned in the transverse direction. A nested scan may be performed if each of sub-gratings G2n in grating G2 are slightly shifted in their position perpendicular to the grating lines.
References (4) to (8) relate to further publications which are based on the research performed at the Paul Scherrer Institut in Switzerland.
As compared to the grating-based phase-contrast X-ray imaging described in References (1) to (8), a different approach in which no grating is required was suggested recently in Reference (9). Reference (9) discloses phase-contrast X-ray imaging system and methods with an application of a field emission X-ray source in phase-contrast imaging, and a multi- source arrangement to acquire phase and phase-contrast images. A partially coherent X-ray beam propagates through an object, and from the image signals of a detector an attenuation-map and a phase-map are retrieved.
Intensity measurements are acquired by the detector at two different positions, either by moving a single detector, or by providing two detectors, one detector reading for determining attenuation, and the other detector reading for determining phase-contrast.
An optimal phase visibility is achieved with a focal spot size of about 25 μm. The X-ray source employed in Reference (9) may be constituted as a field emission device (FED) with a field emission cathode having an array of sharp points or tips. The field emission cathode can be an electron gun made of metallic nanocrystal material with nanocrystals having a size of 1 to 2 nanometres. Since there is necessarily a trade-off between spatial coherence and high X-ray output, the X-ray output may be increased by providing a plurality of X-ray sources. A multi-step exposure process is performed in which only a portion of the X-ray sources generate X-rays during each of the steps of the process. Each of the X-ray sources can be built with a very small focal spot size, resulting in point source operation. The exposure area of each source can have a small size, thus reducing X-ray scatter, and providing improved image contrast and/or reduced object (i.e. patient) radiation. The multi X-ray sources provide a sufficient photo flux.
In summary, in the prior art there are basically two different approaches, the first one relating to grating-based hard X-ray interferometers for obtaining phase-contrast X- ray images as described in References (1) to (8), and the second one relating to phase- contrast X-ray imaging where no gratings are employed, as described in Reference (9).
The present inventors have recognized that each one of the two known approaches has limitations and/or disadvantages. According to the first approach, performing phase-stepping requires the movement of at least one member of the apparatus, whereas according to the second approach either a single detector has to be moved, or two detectors have to be provided.
The object of the invention is to provide an apparatus and method for an improved grating-based phase-contrast X-ray imaging. The invention is indicated in the independent claims. Advantageous embodiments of the invention are indicated in the dependent claims.
The invention will be discribed in more detail hereinafter based on preferred embodiments thereof with reference to the attached drawings in which:
Fig. 1 shows an imaging apparatus according to the present invention; Fig. 2 shows details of the distributed X-ray source array of the apparatus according to the invention;
Fig. 3 shows a prior art imaging system according to references [3-7] with three gratings;
Fig. 4A shows an experimental DPCI setup, taken from references [3-7], with a source grating GO (for spatial beam coherence), a phase grating Gl
(producing an interference pattern between Gl and G2), and an absorber grating G2; Fig. 4B shows cross sections of GO to G2 in Fig. 4A, GO and G2 being filled with gold; Fig. 5 shows an interference pattern created between Gl and G2, demonstrating the "self imaging" effect in characteristic distances di, d2 and d3 (Talbot effect); the relative position of the minima and maxima depends on the phase-shift of the wave front incident on Gl; in typical DPCI Setups, di is in the order of several cm; and Fig. 6 explains the detection of the "differential phase contrast" by shifting the absorber grating G2 in a direction x parallel to the grating planes; the difference in the wave front phase at two positions "1" and "2" can be expected from the phase-shift Cp2-Cp1 of the measured Moire- pattern, here for four sampling positions X1 to X4.
A comparison of Fig. 3 (prior art) with an apparatus according to the present invention as depicted in Fig. 1 shows that according to the present invention a novel X-ray source is provided which does not require a source grating GO (Fig. 3) for providing spatial beam coherence.
A major advantage of the present invention is that none of the members of the imaging apparatus according to the invention needs to be moved. In the technical field of the present invention, movement devices have to be built according to very strict standards for providing the accuracy which is required for interferometers, such that movement devices are very complicated and therefore expensive.
According to the present invention an Y-ray source array is provided including a plurality of distributed X-ray sources. The X-ray source array allows a "virtual movement" of one or more small focal spots created by one ore more distributed X-ray sources.
Preferably, a switching means is provided for switching the plurality of X-ray sources in a predetermined order.
One approach according to the invention is based on a common anode and a thermal electron source (a source for thermal electrons). At least one XY focussing and deflection unit is provided for scanning an electron beam emitted by the electron source on the anode as a target. In this manner, a scanning of the spatial modulated electron beam on the anode target is performed. This replaces the phase stepping of any grating. Several "small" electron beams are focussed to an anode (which may be structured) to have different focus spot positions, each position corresponding to a slit of the grating GO in the prior art.
Another approach according to the invention is the realisation of several distributed small X-ray sources by field emitter devices like carbon nanotube based devices (CNT based X-ray source). An advantage of this approach is the fast switching of the X-ray sources, instead of electron beam scanning according to the thermal electron emitter solution, such that no dynamical beam deflection units will be required.
The design of the emitters (e.g. CMT based) on a substrate, together with the single beam focussing units, has to be done in a way that resulting focus spot movement on the anode has the same effect in combination with the collimator geometry as the scanning movement of the grating GO (prior art) in front of the X-ray tube. In both ways a coherent pattern of single point sources that move along the x-direction is generated.
The geometrical shape and size of each focus spot would be chosen such that, if seen from the view point of the detector, the focus spot has a geometrical structure like a trench at the grating GO according to the prior art. This shaping would be supported by a relatively small anode angle, as an almost squared shape on the anode will turn into a small slit in the view projected to the detector. Distances and focussing have to be designed according to the geometry of focal spot and grating GO of a conventional system, to achieve a comparable coherent x-ray pattern. Details of the multi-pixel, multi-line array according to the present invention are shown in Fig. 2. An offset of 1/4 pixel may be provided for higher spatial resolution.
In summary, the invention provides an imaging apparatus with a switching X- ray source, wherein no mechanical scanning is required, but fast X-ray source switching is employed. The distributed X-ray source array according to the invention generates coherent beams and replaces grating GO (and scanning by grating GO) with scanning/switching of the focal spot points.
The main application of the invention is found in all modalities related to differential phase contrast imaging (DPCI), i.e. in stationary transmission geometries (i.e. mammography, fluoroscopy, etc.), but also in computed tomography (CT) or related rotational X-ray imaging technologies.

Claims

CLAIMS:
1. A grating-based phase-contrast X-ray imaging apparatus comprising an X-ray source array including a plurality of distributed X-ray sources; a phase grating (Gl); an analyzer grating (G2); and an image detector.
2. An imaging system according to claim 1, wherein a switching means is provided for switching the plurality of X-ray sources in a predetermined order.
3. An imaging system according to claim 1 or 2, wherein the X-ray source array comprises a common anode; a thermal electron source; and at least one XY focussing and deflection unit for scanning an electron beam emitted by the electron source on the anode as a target.
4. An imaging system according to claim 3, wherein the anode is a structured anode.
5. An imaging system according to claim 1 or 2, wherein each X-ray source is a field emitter device.
6. An imaging system according to claim 5, wherein the field emitter device is a carbon nanotube (CNT) field emitter device.
7. A method for grating-based X-ray imaging comprising providing a phase grating (Gl), an analyzer grating (G2), and an image detector; providing an X-ray source array including a plurality of distributed Y-ray sources; switching the plurality of X-ray sources in a predetermined order.
8. A method according to claim 7, wherein an electron beam emitted by a thermal electron source on an anode as a target is XY focussed and deflected.
9. A method according to claim 7, wherein each one of the plurality of Y-ray sources is a field emitter device.
10. A method according to claim 9, wherein the field emitter device is a carbon nanotube (CNT) field emitter device.
PCT/IB2010/052656 2009-06-22 2010-06-15 Grating-based phase contrast x-ray imaging apparatus and methods WO2010150136A1 (en)

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EP09163392.5 2009-06-22
EP09163392 2009-06-22

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015037685A1 (en) * 2013-09-11 2015-03-19 Canon Kabushiki Kaisha X-ray imaging system
US8989347B2 (en) 2012-12-19 2015-03-24 General Electric Company Image reconstruction method for differential phase contrast X-ray imaging
US9014333B2 (en) 2012-12-31 2015-04-21 General Electric Company Image reconstruction methods for differential phase contrast X-ray imaging
CN105606633A (en) * 2014-11-04 2016-05-25 清华大学 X-ray phase contrast imaging system and X-ray imaging method
WO2017019782A1 (en) * 2015-07-27 2017-02-02 Rensselaer Polytechnic Institute Combination of an x-ray tube and a source grating with electron beam manipulation
EP3171163A1 (en) * 2015-11-18 2017-05-24 FEI Company Novel x-ray imaging technique
EP3443904A1 (en) * 2017-08-14 2019-02-20 Koninklijke Philips N.V. Multi-spot x-ray imaging
US10485492B2 (en) 2014-11-11 2019-11-26 Koninklijke Philips N.V. Source-detector arrangement
US10660595B2 (en) 2016-06-16 2020-05-26 Koninklijke Philips N.V. Apparatus for x-ray imaging an object
CN111575653A (en) * 2020-05-10 2020-08-25 兰州大学 A kind of X-ray absorption grating and its manufacturing method
US20220328277A1 (en) * 2020-07-06 2022-10-13 Michael Keith Fuller Method and device for producing and using multiple origins of x-radiation
US20230104855A1 (en) * 2021-10-06 2023-04-06 Houxun Miao Interferometer for x-ray phase contrast imaging

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004071209A1 (en) 2003-01-14 2004-08-26 Ajinomoto Co., Inc. Silage additive and process for producing silage using the same
EP1731099A1 (en) 2005-06-06 2006-12-13 Paul Scherrer Institut Interferometer for quantitative phase contrast imaging and tomography with an incoherent polychromatic x-ray source
EP1803398A1 (en) * 2005-12-27 2007-07-04 Siemens Aktiengesellschaft Source-detector arrangement for X-ray phase contrast imaging and method therefor
EP1879020A1 (en) 2006-07-12 2008-01-16 Paul Scherrer Institut X-ray interferometer for phase contrast imaging
JP2008145111A (en) * 2006-12-06 2008-06-26 Univ Of Tokyo X-ray imaging apparatus, X-ray source used therefor, and X-ray imaging method
US7412026B2 (en) 2004-07-02 2008-08-12 The Board Of Regents Of The University Of Oklahoma Phase-contrast x-ray imaging systems and methods
WO2009115966A1 (en) * 2008-03-19 2009-09-24 Koninklijke Philips Electronics N.V. Rotational x ray device for phase contrast imaging

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004071209A1 (en) 2003-01-14 2004-08-26 Ajinomoto Co., Inc. Silage additive and process for producing silage using the same
US7412026B2 (en) 2004-07-02 2008-08-12 The Board Of Regents Of The University Of Oklahoma Phase-contrast x-ray imaging systems and methods
EP1731099A1 (en) 2005-06-06 2006-12-13 Paul Scherrer Institut Interferometer for quantitative phase contrast imaging and tomography with an incoherent polychromatic x-ray source
EP1803398A1 (en) * 2005-12-27 2007-07-04 Siemens Aktiengesellschaft Source-detector arrangement for X-ray phase contrast imaging and method therefor
EP1879020A1 (en) 2006-07-12 2008-01-16 Paul Scherrer Institut X-ray interferometer for phase contrast imaging
JP2008145111A (en) * 2006-12-06 2008-06-26 Univ Of Tokyo X-ray imaging apparatus, X-ray source used therefor, and X-ray imaging method
WO2009115966A1 (en) * 2008-03-19 2009-09-24 Koninklijke Philips Electronics N.V. Rotational x ray device for phase contrast imaging

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
F. PFEIFFER ET AL., EUROPHYSICS NEWS, vol. 37, no. 5, 2006, pages 13
F. PFEIFFER ET AL., NATURE PHYSICS, vol. 2, 2006, pages 258
F. PFEIFFER ET AL., PHYS. REV. LETT., vol. 94, 2005, pages 164801
F. PFEIFFER ET AL., PHYS. REV. LETT., vol. 98, 2007, pages 108105
T. WEITKAMP ET AL., OPTICS EXPRESS, vol. 13, no. 16, 2005, pages 6296

Cited By (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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US9014333B2 (en) 2012-12-31 2015-04-21 General Electric Company Image reconstruction methods for differential phase contrast X-ray imaging
WO2015037685A1 (en) * 2013-09-11 2015-03-19 Canon Kabushiki Kaisha X-ray imaging system
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US10267752B2 (en) 2014-11-04 2019-04-23 Tsinghua University X-ray phase-contrast imaging system and imaging method
EP3048441A4 (en) * 2014-11-04 2017-06-21 Tsinghua University X-ray phase-contrast imaging system and imaging method
US10485492B2 (en) 2014-11-11 2019-11-26 Koninklijke Philips N.V. Source-detector arrangement
US10722201B2 (en) 2015-07-27 2020-07-28 Rensselaer Polytechnic Institute Combination of an X-ray tube and a source grating with electron beam manipulation
WO2017019782A1 (en) * 2015-07-27 2017-02-02 Rensselaer Polytechnic Institute Combination of an x-ray tube and a source grating with electron beam manipulation
EP3171163A1 (en) * 2015-11-18 2017-05-24 FEI Company Novel x-ray imaging technique
JP2017096923A (en) * 2015-11-18 2017-06-01 エフ イー アイ カンパニＦｅｉ Ｃｏｍｐａｎｙ New X-ray imaging technique
US10545100B2 (en) 2015-11-18 2020-01-28 Fei Company X-ray imaging technique
CN106940323A (en) * 2015-11-18 2017-07-11 Fei 公司 New X-ray imaging technology
JP2021139911A (en) * 2015-11-18 2021-09-16 エフ イー アイ カンパニFei Company Novel x-ray imaging technique
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CN111575653A (en) * 2020-05-10 2020-08-25 兰州大学 A kind of X-ray absorption grating and its manufacturing method
US20220328277A1 (en) * 2020-07-06 2022-10-13 Michael Keith Fuller Method and device for producing and using multiple origins of x-radiation
US11844641B2 (en) * 2020-07-06 2023-12-19 Michael Keith Fuller Method and device for producing and using multiple origins of x-radiation
US20230104855A1 (en) * 2021-10-06 2023-04-06 Houxun Miao Interferometer for x-ray phase contrast imaging
US11813102B2 (en) * 2021-10-06 2023-11-14 Houxun Miao Interferometer for x-ray phase contrast imaging

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