Image processing apparatus and X-ray computer tomography apparatus

An X-ray computer tomography apparatus comprising:

• an X-ray tube which generates X-rays;
• an X-ray detector which generates projection data by detecting X-rays transmitted through an object;
• a reconstruction processing unit which reconstructs a plurality of images based on the projection data;
• and
• an image processing unit which processes the images, the image processing unit including
• a storage unit which stores data of the plurality of images,
• a reference point determining unit which determines, from each of the images, a reference point which is located in or near a region of the examination target organ and undergoes a relatively small displacement accompanying respiratory motion, and
• a moving amount calculation unit which determines a position of each of a plurality of points of interest included in the region of the examination target organ relative to the reference point for each of the images, and calculates, directly based on the determined positions and the reference point, moving amounts for the corresponding points of interest between the images accompanying the respiratory motion.

An image processing apparatus comprising:

• a storage unit configured to store data of at least 3-dimensional X-ray CT images which include an examination target organ of an object and which are taken in different phases of respiration;
• a reference point determining unit configured to determine a reference point located in or near the examination target organ, from the 3-dimensional X-ray CT images;
• and
• a moving amount calculation unit configured to determine a plurality of points of interest on the 3-dimensional X-ray CT images of the examination target organ, and to calculate a moving amount by which each of the points of interest moves as a result of a phase change of respiration, relative to the reference point.