<；P>；PROBLEM TO BE SOLVED: To provide a medical image processor and a medical image processing method suitable for kinetics observation. <；P>；SOLUTION: This medical image processor includes: a first image generation part for extracting data on a region of interest from a volume data, and performing volume rendering using the extracted data on the region of interest to obtain a three-dimensional image of the region of interest seen from a predetermined line of sight direction on a two-dimensional projection plane； a distance information generating part for calculating a distance from the two-dimensional projection plane to the boundary surface of the region of interest along the direction of line of sight based on the volume data of time phase before and after in point of time, and generating distance information in every time phase； a differential value calculating part for acquiring the distance information of two time phases before and after in point of time and calculating a differential value of the respective distance information pieces； a second image generating part for generating an additional image changing in density according to the magnitude of the calculated differential value； and a composing part for composing an additional image with the three-dimensional image obtained in the first image generating part. <；P>；COPYRIGHT: (C)2008,JPO&INPIT
