Classifications

• • 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
• • 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
  • A61B6/405—Source units specially adapted to modify characteristics of the beam during the data acquisition process
• • 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
  • A61B6/4241—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector using energy resolving detectors, e.g. photon counting
• • 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
  • A61B6/482—Diagnostic techniques involving multiple energy imaging
• • 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 concerns an X-ray imaging system for imaging an object of interest, a method for X-ray imaging, a computer program element, a computer-readable medium, and a kit of parts for retrofitting a legacy X-ray scanner.
• an X-ray source illuminates a phase grating, which establishes an interferometric pattern of X-ray maxima and minima beyond the phase grating, detected at an X-ray detector.
• a change in the phase in a portion of an X- ray beam incident on the phase grating will cause a related portion of an interferometric pattern to be displaced in the plane of the X-ray detector.
• a resolution of an X-ray detector is often not good enough to sample the interference pattern directly. Therefore, a movable analyzer grating is provided.
• a phase contrast imager samples the interference pattern by moving the analyzer grating a fixed number of steps across the plane of the X-ray detector, thus deriving information on the phase shift.
• WO 2014/206841 concerns a phase-contrast imaging system. Such systems can, however, be further improved.
• a first aspect of the invention provides an X-ray imaging system for imaging an object of interest.
• the system comprises an X-ray source, a phase grating, an analyzer grating, an X-ray detector, and a processing unit.
• the X-ray source, the phase grating, the analyzer grating, and the X-ray detector are arranged in an optical path.
• the X-ray source is configured to apply X-rays to an object of interest positionable in the optical path.
• the analyzer grating is provided in proximity to, or formed integrally with, the X-ray detector.
• the phase grating is configured to generate an interference pattern in the X- ray radiation comprising an intensity profile having an intensity peak with a full-width half- maximum distance which is narrow in comparison to a width of a transparent section of the analyzer grating, wherein the intensity peak of the interference pattern is incident on the X- ray detector through the transparent section of the analyzer grating.
• the X-ray detector is configured to generate a first X-ray signal by measuring a first interference pattern and a second X-ray signal by independently measuring a second interference pattern.
• the interference patterns which are generated by means of the phase grating, are indicative of an interaction of the X-ray radiation with an object of interest in the optical path. In generating the first and second X-ray signals, a difference in physical characteristics of the X-ray radiation used is being exploited.
• the processing unit is configured to calculate an attenuation component and a dark-field component of the first and second interference patterns using the first and second X-ray signals.
• phase grating configured to generate an interference pattern in the X-ray radiation comprising an intensity profile having an intensity peak with a full- width half-maximum distance which is narrow in comparison to a width of a transparent section of the analyzer grating, wherein the intensity peak of the interference pattern is incident on the X-ray detector through the transparent section of the analyzer grating;
• a computer program element for controlling a system as described above, which, when being executed by a processing unit, is adapted to perform the method steps as described above.
• the kit of parts comprises an X-ray detector having an analyzer grating in proximity to, or formed integrally with, the X-ray detector, a phase grating configured to generate an interference pattern in X-ray radiation, comprising an intensity profile having an intensity peak with a full- width half-maximum distance which is narrow in comparison to a width of a transparent section of the analyzer grating, wherein the intensity peak of the interference pattern is incident on the installed X-ray detector through a transparent section of the analyzer grating, and a computer-readable medium according to the description above.
• the present invention allows for useful application in a clinical environment such as a hospital. More specifically, the present invention is very suitable for application in imaging modalities such as mammography, diagnostic radiology, interventional radiology and computed tomography (CT) for the medical examination of patients.
• CT computed tomography
• the presentation invention allows for useful application in an industrial environment. More specifically, the present invention is very suitable for application in non-destructive testing (e.g. analysis as to composition, structure and/or qualities of biological as well non-biological samples) as well as security scanning (e.g. scanning of luggage on airports).
• non-destructive testing e.g. analysis as to composition, structure and/or qualities of biological as well non-biological samples
• security scanning e.g. scanning of luggage on airports.
• the physical characteristic being different is an energy level of the X-ray radiation.
• the X-ray detector may be an energy sensitive detector configured to generate the first X-ray signal by detecting a first photon energy, and to generate the second X-ray signal by detecting a second photon energy, wherein the first and second photon energies are mutually different.
• use is made of a difference in a coherence of the X-ray radiation.
• the X-ray imaging system is configured to generate each of the first X-ray signal and the second X-ray signal as composite signals, wherein with the first X-ray signal is based on a first measurement made with coherent X-rays, and a second measurement made with incoherent X-rays, and wherein the second X-ray signal is based on a third measurement made with coherent X-rays, and a fourth measurement made with incoherent X-rays.
• the phase grating 14 is configured to generate an interference pattern in the X- ray radiation comprising an intensity profile having a maximum with a full-width half- maximum distance which is narrow in comparison to a width of a transparent section of the analyzer grating.
• the intensity maximum is incident on the X-ray detector 18 through the transparent section of the analyzer grating.
• a Talbot interferometer is applied, using a special grating capable of generating suitable X-ray interferometric patterns with a plurality of fine interference maxima.
• the analyzer grating is provided in proximity to, or formed integrally with, the X-ray detector 18 (fabricated in the silicon wafer 52). Therefore, in the embodiment illustrated in Fig. 3, the analyzer grating line 54 is attached directly to the silicon wafer 52, for example, because it has been deposited in a deposition process. Alternatively, the analyzer grating line 54 may be arranged on another X-ray transparent material, and held proximately to the silicon wafer 52.
• the X-ray imaging system 10 is provided as described previously, wherein the phase grating 14 is configured to provide the interference pattern with a full- width at half-maximum distance smaller than any value selected from the list of 0.7, 0.65, 0.60, 0.55, 0.50, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05, 0.04, 0.03, 0.02, or 0.01 of the period of the analyzer grating.
• an intensity peak which is narrow in comparison to a width of a transparent section of the analyzer grating may be one with dimensions selected according at least to the above definitions.
• the duty cycle of the analyzer grating and/or the phase grating is more than a value selected from the list: 0.5, 0.51, 0.52, 0.53, 0.54, 0.55, 0.56, 0.57, 0.58, 0.59, 0.6, 0.61, 0.62, 0.63, 0.64, 0.65, 0.66, 0.67, 0.68, 0.69, 0.70, 0.71, 0.72, 0.73, 0.74, 0.75, 0.76, 0.77, 0.78, 0.79, 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, 0.95.
• the X-ray detector 18 may be an energy-resolving detector, such as a photon counter employing multiple energy bins.
• the X-ray source emits polychromatic radiation.
• the energy resolving detector is used to detect the attenuation or small angle scatter of incident X-rays for different energy ranges. Therefore, two independent intensity profiles may be detected by using an energy resolving detector.
• the X-ray imaging system 10 as discussed above is provided, wherein the X-ray detector 18 is an energy sensitive detector configured to generate the first X-ray signal by detecting a first detected photon energy, and to generate the second X-ray signal by detecting a second detected photon energy, wherein the first and second detected photon energies are mutually different.
• the X-ray detector 18 is an energy sensitive detector configured to generate the first X-ray signal by detecting a first detected photon energy, and to generate the second X-ray signal by detecting a second detected photon energy, wherein the first and second detected photon energies are mutually different.
• first and second photon energy ranges are applicable, for example, to a mammography system:
• the first detected photon energy is in the range 5-15 keV and the second detected photon energy is in the range 15-40 keV.
• the first detected photon energy is in the range 5-25 keV and the second detected photon energy is in the range 25-40 keV. According to an embodiment of the invention, the first detected photon energy is in the range 5-30 keV and the second detected photon energy is in the range 30-40 keV.
• Such an approach is implemented by providing a model for the energy dependent attenuation, and visibility, and spectral response of the detector.
• the model will depend on the specific form of the intensity profile, for example.
• a lookup table derived by measurement of a phantom comprising different materials.
• TM Delrin
• TM a phantom made of Delrin (TM) (being a material having a water-equivalent spectral attenuation) and a strong scattering material with negligible attenuation
• the photon-counting results are mapped to the effective Delrin (TM) length, and scatter material length, which are then translated into the attenuation and dark- field signal.
• an equivalent approach would be to remove the source-grating 26 from an output port of the X-ray source 12 to enable the incoherent light from the X-ray tube 24 to be applied directly to the object of interest 28. Therefore, according to the above-described embodiments, an intensity measurement is made using the X-ray detector 18 using coherent X-rays, and then incoherent X-rays being applied.
• the X-ray imaging system 10 is configured to generate the first X-ray signal by measuring the second interference pattern when an object of interest is present in the optical path 22.
• the four measured signals per detector pixel can be provided as: siglo, siglVo, sigl and siglV.
• a first set of coherent and incoherent measurements are taken by the CT scanner's detector when no object of interest is present in the optical path
• a second set of coherent and incoherent measurements are taken by the CT scanner's detector when the object of interest is positioned in the optical path.
• a computer program element for controlling a system according to one of the previous descriptions of the X-ray system which, when being executed by a processing unit, is adapted to perform the method steps according to one of the previous methods.
• a computer program element might be stored on a computer unit which could also be an embodiment of the invention.
• the computing unit may be adapted to perform or induce performance of the steps of the method described above. Moreover, it may be adapted to operate the components of the above-described apparatus.
• a medium for making a computer program element available for downloading is provided, which computer program element is arranged to perform a method according to one of the previously described embodiments of the invention.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Medical Informatics (AREA)
• Heart & Thoracic Surgery (AREA)
• Molecular Biology (AREA)
• Biophysics (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Optics & Photonics (AREA)
• Pathology (AREA)
• Radiology & Medical Imaging (AREA)
• Biomedical Technology (AREA)
• Physics & Mathematics (AREA)
• High Energy & Nuclear Physics (AREA)
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• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Pulmonology (AREA)
• Theoretical Computer Science (AREA)
• Analysing Materials By The Use Of Radiation (AREA)
• Measurement Of Radiation (AREA)
• Apparatus For Radiation Diagnosis (AREA)

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• 2016
  • 2016-05-06 CN CN201680026177.6A patent/CN107580473A/zh active Pending
  • 2016-05-06 US US15/569,832 patent/US20180140269A1/en not_active Abandoned
  • 2016-05-06 WO PCT/EP2016/060166 patent/WO2016177875A1/en not_active Ceased
  • 2016-05-06 JP JP2017557043A patent/JP2018519866A/ja active Pending
  • 2016-05-06 EP EP16722619.0A patent/EP3291732A1/en not_active Withdrawn

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