Patent ID: 8403821

Claim:
A radiotherapy apparatus controller comprising: an imperfect three-dimensional data calculating unit configured to calculate an imperfect three-dimensional data based on a plurality of imperfect transmission images which are respectively imaged from a plurality of imperfect directions except a predetermined direction among a plurality of directions different from each other; an imaging unit configured to image an additional transmission image from said predetermined direction by using an imager system; a perfect three-dimensional data calculating unit configured to calculate a perfect three-dimensional data based on said additional transmission image and said imperfect three-dimensional data; a position calculating unit configured to calculate a position of a part of a subject based on said perfect three-dimensional data; and a shift amount calculating unit configured to calculate a shift amount based on said additional transmission image and said imperfect three-dimensional data, wherein said perfect three-dimensional data calculating unit calculates said perfect three-dimensional data based on a post-shift transmission image in which an image shown in said additional transmission image is shifted by said shift amount and shown.