1. A method of generating an image of an organ, the method comprising: generating a three-dimensional (3D) model of an organ of a patient based on a first medical image of the organ; generating a plurality of matched images by matching the 3D model of the organ to a plurality of images indicating a change in a shape of the organ based on movement of the organ; and selecting and outputting a matched image from among the plurality of matched images based on a region of a second medical image of the organ, wherein the selecting and outputting comprises setting a plurality of candidate regions in the second medical image; selecting a candidate region from among the plurality of candidate regions, wherein the candidate region is selected based on a result obtained by combining a noise level of each of the plurality of candidate regions with a motion distance of the organ between inspiration and expiration of the organ in each of the plurality of candidate regions; and selecting and outputting the matched image from among the plurality of matched images based on the selected candidate region.