PROBLEM TO BE SOLVED: To generate a curved cross sectional image suitable to observe a portion of interest from a three-dimensional tomographic image.SOLUTION: An image processor includes a reference portion acquisition part for acquiring a first reference portion and a second reference portion from a three-dimensional image of a subject, a surface of interest calculation part for calculating a curved surface of interest between the first reference portion and the second reference portion by using an absolute distance from the first reference portion or a relative distance to a distance up to the second reference portion, and an image generation part for generating a curved cross sectional image in a curved surface of interest from the three-dimensional image.SELECTED DRAWING: Figure 1
