An apparatus for generating X-ray imaging data, comprising: - an X-ray source ; - a first grating ; - a second grating ; - a third grating ; and - an X-ray detector ; wherein, the X-ray source is configured to produce X-rays; wherein, the first grating is positioned between the X-ray source and the second grating; wherein, the second grating is positioned between the first grating and the third grating; wherein, the third grating is positioned between the second grating and the X-ray detector; wherein, at least part of the region between the first grating and the third grating forms an examination region for accommodating an object; wherein, either the first grating or the third grating has a pitch attribute of having a constant grating pitch; wherein, both gratings of an adjacent pair of gratings have a pitch attribute of having a varying grating pitch; wherein, both gratings of an adjacent pair of gratings are bent such that a distance between the two adjacent gratings is constant as a function of fan angle; and wherein, the X-ray detector is configured to detect at least some of the X-rays transmitted by the three gratings. - an X-ray source ; - a first grating ; - a second grating ; - a third grating ; and - an X-ray detector ; wherein, the X-ray source is configured to produce X-rays; wherein, the first grating is positioned between the X-ray source and the second grating; wherein, the second grating is positioned between the first grating and the third grating; wherein, the third grating is positioned between the second grating and the X-ray detector; wherein, at least part of the region between the first grating and the third grating forms an examination region for accommodating an object; wherein, either the first grating or the third grating has a pitch attribute of having a constant grating pitch; wherein, both gratings of an adjacent pair of gratings have a pitch attribute of having a varying grating pitch; wherein, both gratings of an adjacent pair of gratings are bent such that a distance between the two adjacent gratings is constant as a function of fan angle; and wherein, the X-ray detector is configured to detect at least some of the X-rays transmitted by the three gratings. wherein, the X-ray source is configured to produce X-rays; wherein, the first grating is positioned between the X-ray source and the second grating; wherein, the second grating is positioned between the first grating and the third grating; wherein, the third grating is positioned between the second grating and the X-ray detector; wherein, at least part of the region between the first grating and the third grating forms an examination region for accommodating an object; wherein, either the first grating or the third grating has a pitch attribute of having a constant grating pitch; wherein, both gratings of an adjacent pair of gratings have a pitch attribute of having a varying grating pitch; wherein, both gratings of an adjacent pair of gratings are bent such that a distance between the two adjacent gratings is constant as a function of fan angle; and wherein, the X-ray detector is configured to detect at least some of the X-rays transmitted by the three gratings. <EOS>