Patent US 5,285,787

A method of calculating coordinate data of a desired point in a subject to be examined is disclosed. A phantom image is obtained by integrally photographing a second frame, a frame coordinate phantom, and a second indicator phantom by using a computed tomographic apparatus. A subject image is then obtained by integrally photographing a first frame, the subject, and a first indicator phantom at the same position assumed when the phantom image is photographed. Coordinate data is obtained by correcting the deviation between the coordinates of the subject on the real space and the coordinates of the subject on the image photographed by the computed tomographic apparatus.