Patent ID: 8009796

Claim:
An x-ray CT system comprising: a source/detector system that generates tomographical phase contrast or dark field exposures, said source/detector system being mounted on a gantry rotatable around a system axis, said source/detector system comprising an x-ray source having a grating structure that emits bands of emission maxima and emission minima of a generated x-ray radiation arranged like a grating, with a grating period (p 0 ), that emits a beam fan of x-rays widening in two places with a max fan angle (2xφ max ) in the rotation plane of the gantry and a Z-angle (2xξ max ) perpendicular to the rotation plane of the gantry; said source/detector system comprising a detector arrangement with a plurality of grating/detector modules arranged in parallel, each module comprising, one after another in the beam direction, at least one phase grating (G 1i ) that generates an interference pattern, an analysis grating (G 2i ) with a directly connected detector with a plurality of detector elements to determine phase (x 0 ), average radiation intensity (I med ) and amplitude (I amp ) of the average intensity of the radiation per detector element given relative displacement of one of the upstream grating structures, the grating lines of all grating structures (G 0 , G 1i , G 2i ) being aligned parallel to one another and parallel to the system axis; and a distance (I) between the grating structure (G 0 ) of the x-ray source and the phase grating (G 1,i ) of the respective grating/detector modules being adapted depending on the fan angle corresponding to a period (p 0i ') of the grating structure (G 0 ) of the x-ray source that is projected onto the grating/detector module at the respective fan angle (φ i ).