A grating with a large aspect ratio is disclosed, in particular to be used as an X-ray optical grating in a CT system and in particular produced by a lithography method. In at least one embodiment, the grating includes a multiplicity of recurring alternating grating webs and grating gaps with a height, and a multiplicity of filler beams, respectively arranged in the grating gaps with a spacing from one another in the direction of the gaps, which beams connect respectively adjacent grating webs over their height. In at least one embodiment, the grating webs and the grating gaps run from a first to a second side of the grating, and a filler beam has a width in the direction of the gaps and this width is at most 10% of the spacing between two adjacent filler beams. In at least one embodiment, the spacings between respective adjacent filler beams in a grating gap do not vary by more than 10% in the entire grating. At least one embodiment of the invention furthermore relates to a CT system containing at least one grating according to at least one embodiment of the invention.