1. A CT system for phase-contrast and absorption imaging, comprising: a gantry, rotatable about a system axis; at least two emitter-detector systems, attached to the gantry with an angular offset to scan a measurement field, a specified distance existing between a radiation focus in a respective emitter and a respective detector with its detector elements in each of the at least two emitter-detector systems, measurement beams being defined by a geometric connection between respective a radiation focus and detector element, and at least two of the at least two emitter-detector systems including different distances between respective radiation focus and detectors; and a computational and control unit configured to control the CT system, the computational and control unit including a computational element configured to solve a transport intensity equation on the basis of at least two projections recorded at the same projection angle at different distances, which outputs phase and intensity values of the measurement beams for a multiplicity of projection angles, and including a computational element configured to reconstruct tomographic image data from at least one of the calculated phase values and intensity values.