Patent ID: 8873819

Claim:
A method for sorting CT image slices, comprising: determining a breathing feature value and a respiratory phase for each image slice of the CT image slices, wherein the CT image slices comprise a plurality of image slices at each of a plurality of couch positions; and, for a target respiratory phase, sorting an image slice comprising the target respiratory phase from the plurality of image slices at each of the plurality of couch positions for constructing the 3D CT image for the target respiratory phase, wherein, if no image slice comprises the target respiratory phase at a couch position, the method further comprises: determining a target breathing feature value corresponding to the target respiratory phase based on a respiratory motion curve of a scanned patient; searching from the plurality of image slices at the couch position for one or more image slices comprising a breathing feature value close to the target breathing feature value to serve as candidate image slices; and selecting, based on a breathing feature value difference between the breathing feature value of each of the candidate image slices and the target breathing feature value and/or an image difference between each of the candidate image slices and at least one reference image slice, a single image slice from the candidate image slices for constructing the 3D CT image for the target respiratory phase.