Method for producing projective and tomographic phase contrast images with the aid of an X-ray system

An X-ray CT system for producing tomographic phase contrast images, comprising:

• at least one focus/detector system arranged on at least one of a gantry and a C arc to rotate about an examination object;
• a set of transirradiated X-ray optical gratings between the focus and detector, including at least one source grating, at least two phase gratings alternately movable into the beam path, and an analyzer grating;
• and
• a control unit that contains program code for,
• measuring a quantitative phase displacement of an X-radiation penetrating an examination object in an energy-specific fashion with reference to at least two different energy ranges, and
• forming recorded values as a function of the energy-specific quantitative phase displacements.

An X-ray CT system for producing tomographic phase contrast images, comprising:

• at least two focus/detector systems arranged on at least one of a gantry and a C arc to rotate about an examination object;
• for each focus/detector system, a set of transirradiated X-ray optical gratings, dimensioned in an energy-specific fashion, between the focus and detector and including a source grating, a phase grating and an analyzer grating;
• and
• a control unit that contains program code for,
• measuring a quantitative phase displacement of an X-radiation penetrating an examination object in an energy-specific fashion with reference to at least two different energy ranges, and
• forming recorded values as a function of the energy-specific quantitative phase displacements.

An X-ray CT system for producing tomographic phase contrast images, comprising:

• at least one focus/detector system arranged on at least one of a gantry and a C arc to rotate about an examination object;
• a set of transirradiated X-ray optical gratings between the focus and detector, including at least one source grating, at least two phase gratings alternately movable into the beam path, and an analyzer grating;
• and
• an arithmetic and control unit that contains program code fort
• measuring a quantitative phase displacement of an X-radiation penetrating the examination object in an energy-specific fashion with reference to at least two different energy ranges, and
• forming recorded values as a function of the energy-specific quantitative phase displacements.

A focus/detector system of an X-ray apparatus, comprising:

• a radiation source with a focus and an opposing planar detector with a multiplicity of detector elements;
• a set of transirradiated X-ray optical gratings of parallel alignment, arranged between the focus and detector and by which a quantitative phase displacement in the radiation upon penetration of the examination object is measureable in a beamwise resolved fashion, the grating set including,
• at least one source grating arranged between the at least one focus and the examination object,
• at least two phase gratings arrangeable between the examination object and the detector and alternately introduceable into the beam path,
• an analyzer grating arranged upstream of the detector, and
• an apparatus for the relative displacement of the analyzer grating with reference to the phase gratings in a fashion perpendicular to the beam direction and perpendicular to the longitudinal direction of the grating lines;
• and
• a control unit that contains program code for,
• measuring the quantitative phase displacement of an X-radiation penetrating an examination object in an energy-specific fashion with reference to at least two different energy ranges, and
• forming recorded values as a function of the energy-specific quantitative phase displacements.

A focus/detector system of an X-ray apparatus, comprising:

• a radiation source with a focus and an opposing planar detector with a multiplicity of detector elements;
• a set of transirradiated X-ray optical gratings of parallel alignment, arranged between the focus and detector and by which a quantitative phase displacement in the radiation upon penetration of the examination object is measureable in a beamwise resolved fashion, the grating set including
• at least one source grating arranged between the at least one focus and the examination object,
• at least two phase gratings arrangeable between the examination object and the detector and alternately introduceable into the beam path,
• an analyzer grating arranged upstream of the detector, and
• an apparatus for the relative displacement of the analyzer grating with reference to the phase gratings in a fashion perpendicular to the beam direction and perpendicular to the longitudinal direction of the grating lines;
• and
• an arithmetic and control unit that contains program code for execution of,
• measuring the quantitative phase displacement of an X-radiation penetrating the examination object in an energy-specific fashion with reference to at least two different energy ranges, and
• forming recorded values as a function of the energy-specific quantitative phase displacements.

A focus/detector system of an X-ray apparatus, comprising:

• a radiation source with a focus and an opposing planar detector with a multiplicity of detector elements;
• a set of transirradiated X-ray optical gratings of parallel alignment, arranged between the focus and detector and by which the phase shift in the radiation upon penetration of the examination object is measureable in a beamwise resolved fashion, the grating set including
• at least one source grating arranged between the at least one focus and the examination object,
• at least two phase gratings arrangeable between the examination object and the detector and alternately introduceable into the beam path,
• an analyzer grating arranged upstream of the detector, and
• an apparatus for the relative displacement of the analyzer grating with reference to the phase gratings in a fashion perpendicular to the beam direction and perpendicular to the longitudinal direction of the grating lines;
• and
• an arithmetic and control unit that contains program code for exeei44 on measuring a phase shift of an X-radiation penetrating the examination object in an energy-specific fashion with reference to at least two different energy ranges, and
• forming recorded values as a function of the energy-specific phase shifts, wherein in order to produce the projective phase contrast images,
• the examination object is transirradiated by a beam emanating from the focus of an X-ray tube,
• the received radiation intensity is measured with a detector, there being arranged between the at least one X-ray tube and the detector a set of X-ray optical gratings comprising at least one source grating, at least two different phase gratings alternately introduced into the beam path, and an analyzer grating,
• for each beam that lies in space between the focus and detector and penetrates the examination object, the phase shift of this beam upon penetrating the object is determined by at least three intensity measurements with the aid of an analyzer grating arranged in each case with a different offset, and
• for each beam the pixel values are calculated as a function of the energy-specific phase shifts from the measured phase shifts for different energy ranges of each beam.

A storage medium for an X-ray system, wherein the storage medium contains program code that, when executed, causes the X-ray system to perform a method comprising:

• measuring a phase shift of an X-radiation penetrating the examination object in an energy-specific fashion with reference to at least two different energy ranges, and
• forming recorded values as a function of the energy-specific phase shifts, wherein in order to produce the projective phase contrast images,
• the examination object is transirradiated by a beam emanating from the focus of an X-ray tube,
• the received radiation intensity is measured with a detector, there being arranged between the at least one X-ray tube and the detector a set of X-ray optical gratings comprising at least one source grating, at least two different phase gratings alternately introduced into the beam path, and an analyzer grating,
• for each beam that lies in space between the focus and detector and penetrates the examination object, the phase shift of this beam upon penetrating the object is determined by at least three intensity measurements with the aid of an analyzer grating arranged in each case with a different offset, and
• for each beam the pixel values are calculated as a function of the energy-specific phase shifts from the measured phase shifts for different energy ranges of each beam.

An X-ray CT system for producing tomographic phase contrast images, comprising:

• at least one focus/detector system arranged on at least one of a gantry and a C arc to rotate about an examination object;
• a set of transirradiated X-ray optical gratings between the focus and detector, including at least one source grating, at least two phase gratings alternately movable into the beam path, and an analyzer grating;
• and
• at least one further focus/detector system, arranged with an angular offset on the at least one of the gantry and the c arc, which is free from X-ray optical gratings and serves exclusively for absorption measurement.