1. A method for motion correction of emission computed tomography data in a combination device for magnetic resonance tomography and emission computed tomography, the method comprising: recording emission computed tomography data over a recording period and storing associated detection events and detection instants; performing seperate magnetic resonance measurements for at least two subregions of an examination region of an examination object to record magnetic resonance data of the at least two subregions at at least two recording instants during the recording period of the emission computed tomography data; storing the recorded magnetic resonance data and the at least two recording instants; determining, for each of the at least two subregions, at least one item of motion information describing a motion of a region of the examination object at a first instant relative to a position at a second instant, from magnetic resonance data recorded at the first instant and the second instant; determining a motion model describing motion of the examination object, for the entire examination object, from the items of motion information for the at least two subregions; and calculating motion-corrected emission tomography data from the detection events, the detection instants and the motion model.