1. A method for correcting motion in an image reconstructed from raw data, comprising: identifying a plurality of intermediate region of interest images from segments of the raw data for a number of short time frames; adjusting, for each of the plurality of intermediate region of interest images, a voxel value for one or more voxels that reside inside each intermediate region of interest and that intersect a corresponding line of response; computing a characteristic feature for each of the intermediate region of interest images; computing a difference between each characteristic feature and a selected characteristic feature; computing a motion correction vector based on the differences; correcting the raw data motion correction vector; and reconstructing a motion-corrected image corresponding to the region of interest with the corrected raw data.