1. A method for motion correction in time-of-flight positron emission tomography, the method comprising: acquiring, from a memory, a motion vector field for motion of tissue of a patient over a plurality of phases of a physiological cycle; acquiring, with a positron emission tomography (PET) scanner having a plurality of detectors, time of flight data along lines-of-response from emissions, the time of flight data being in a plurality of sets for the respective plurality of phases; forward projecting the motion vector field along at least one dimension; combining the time of flight data for the plurality of phases as a function of the forward projection of the motion vector field; reconstructing an image from the combined time of flight data from the plurality of phases; and displaying the image.