Focus detector arrangement and method for generating contrast x-ray images

An x-ray system comprising:

• a radiation source located at a first side of an examination subject, that generates a beam of coherent x-ray radiation with a grid-like origin;
• a phase grid located in a path of said beam at an opposite, second side of the examination subject, said phase grid comprising spaced-apart grid lines that diffract adjacent coherent rays in said beam to generate an interference pattern of the x-ray radiation in a predetermined energy range of the x-ray radiation dependent on a phase shift of the x-ray beam produced by tissue of the examination subject;
• an analysis-detector system that detects at least said interference pattern generated by said phase grid relative to a local intensity distribution thereof, to determine a local phase shift;
• said radiation source comprising an anode from which said beam of coherent x-ray radiation with a grid-like origin is emitted, said anode comprising regions with respectively different radiation emission characteristics proceeding in spaced-apart bands that are parallel to the grid lines of the phase grid;
• a radiation detector that detects said x-ray radiation after attenuation thereof by said examination subject, said radiation detector emitting detector output signals representing said attenuation;
• and
• an image reconstruction computer supplied with said detector output signals, configured to reconstruct a projection phase-contrast image of the examination subject therefrom.

An x-ray computed tomography system comprising:

• a radiation source located at a first side of an examination subject, that generates a beam of coherent x-ray radiation with a grid-like origin;
• a phase grid located in a path of said beam at an opposite, second side of the examination subject, said phase grid comprising spaced-apart grid lines that diffract adjacent coherent rays in said beam to generate an interference pattern of the x-ray radiation in a predetermined energy range of the x-ray radiation dependent on a phase shift of the x-ray beam produced by tissue of the examination subject;
• an analysis-detector system that detects at least said interference pattern generated by said phase grid relative to a local intensity distribution thereof, to determine a local phase shift;
• said radiation source comprising an anode from which said beam of coherent x-ray radiation with a grid-like origin is emitted, said anode comprising regions with respectively different radiation emission characteristics proceeding in spaced-apart bands that are parallel to the grid lines of the phase grid;
• a radiation detector that detects said x-ray radiation after attenuation thereof by said examination subject, said radiation detector emitting detector output signals representing said attenuation;
• a rotation unit selected from the group consisting of a C-arm and a gantry, at which said x-ray source and said radiation detector are mounted, that rotates said x-ray source and said radiation detector around the examination subject while irradiating the examination subject with said x-ray radiation and while detecting attenuation of the x-ray radiation by said subject with said radiation detector;
• and
• an image computer supplied with said detector output signals configured to reconstruct an image of the examination subject therefrom, selected from the group consisting of projection phase-contrast images and tomographic phase contrast images.

A method for generating projection or tomographic phase contrast exposures of an examination subject using an x-ray apparatus, comprising the steps of:

• emitting a beam of coherent x-ray radiation with a grid-like origin from an anode in a radiation source and irradiating a subject with said x-ray radiation from a first side of the examination subject;
• generating an interference pattern with a phase grid located in a path of said beam at an opposite, second side of the examination subject, said phase grid comprising spaced-apart grid lines that diffract adjacent coherent rays in said beam to generate said interference pattern of the x-ray radiation in a predetermined energy range of the x-ray radiation dependent on a phase shift of the x-ray beam produced by tissue of the examination subject;
• automatically detecting at least said interference pattern generated by said phase grid relative to a local intensity distribution thereof, to determine a local phase shift;
• and
• emitting said beam of coherent x-ray radiation with a grid-like origin from said anode by producing regions on said anode with respectively different radiation emission characteristics proceeding in spaced-apart bands that are parallel to the grid lines of the phase grid.