1. A medical image processing apparatus deforming a plurality of image data, comprising: an image data storage that stores at least two image data of different phases of single target object; a node creating portion that creates nodes, wherein the nodes are related to positions in each of the at least two image data; a local force field calculating portion that calculates local force fields for the nodes, based on positions of the nodes and the at least two image data; a local force calculating portion that calculates local forces, each of which is acted in a corresponding one of the local force fields, from the local force fields; and an image deforming portion that deforms the positions of the nodes based on the local forces.