PROBLEM TO BE SOLVED: To project onto a subject a projection image generated based on a three-dimensional image of the subject so as to reflect changes in conditions of the subject during changes.SOLUTION: The image processing apparatus comprises: acquisition means 1511 for acquiring a three-dimensional image showing a predetermined site of a subject； and generation means 1519 for generating a projection image based on the three-dimensional image, the projection image being related to the predetermined site and being projected onto a projection region of the subject containing the predetermined site. The acquisition means reacquires the three-dimensional image after acquisition of the image. The generation means regenerates the projection image based on the reacquired three-dimensional image.SELECTED DRAWING: Figure 2【課題】被検体の状態の変化を反映しながら被検体の３次元画像に基づいて生成される投影画像を被検体に投影する。【解決手段】画像処理装置は、被検体の所定部位を表す３次元画像を取得する取得手段１５１１と、所定部位を含む被検体の投影領域に投影される投影画像であって且つ所定部位に関連する投影画像を、３次元画像に基づいて生成する生成手段１５１９とを備え、取得手段は、３次元画像を一旦取得した後に、３次元画像を再取得し、生成手段は、再取得された３次元画像に基づいて、投影画像を再生成する。【選択図】図２
