PROBLEM TO BE SOLVED: To provide a positioning device capable of accurately obtaining a change amount by three-dimensionally collating a lesion reference position when a treatment is planned and a lesion position during the treatment.SOLUTION: During the treatment, a two-dimensional X-ray image of a lesion on a treatment base is imaged from a plurality of directions to acquire two or more pieces of two-dimensional X-ray image data in X-ray image acquisition parts 4 and 5, a two-dimensional silhouette of the lesion is extracted from each of a plurality of two-dimensional X-ray images in a silhouette extraction part 7, a three-dimensional surface shape of the lesion is restored from a visual volume cross part of a plurality of two-dimensional silhouettes in a visual volume cross constitution part 8, and the change amount of the position of the lesion during the treatment to the reference position of the lesion when the treatment is planned is calculated by collating three-dimensional CT data of the lesion acquired when the treatment is planned and the three-dimensional surface shape in a change amount calculation part 9.COPYRIGHT: (C)2013,JPO&INPIT【課題】治療計画時の患部基準位置と、治療時の患部位置とを、3次元照合することによって、正確に変化量を求められる位置決め装置を提供する。【解決手段】治療時に、X線画像取得部4、5にて、治療台上での患部の2次元X線画像を複数の方向から撮像し、複数の2次元X線画像データを取得し、シルエット抽出部7にて、複数の2次元X線画像のそれぞれから患部の2次元シルエットを抽出し、視体積交差構成部8にて、複数の2次元シルエットの視体積交差部分から患部の3次元表面形状を復元し、変化量算出部9にて、治療計画時の患部の基準位置に対する、治療時の患部の位置の変化量を、治療計画時に取得した患部の3次元CTデータと3次元表面形状との照合によって算出する。【選択図】図5
