STEREOTAKTISCHES GERAET

摘要

A stereotactics apparatus comprises a frame fixed on a head of a patient and a marker member fixed on the frame. The frame has a frame coordinate system within which the head and the marker member are located. The marker member is tomographically imaged together with the head by a tomographic imaging apparatus (e.g. MRI apparatus), and is displayed as marker image together with the tomographic image of the head. The coordinate system is reconstructed on the basis of the displayed marker image, so that coordinates of the surgical target are calculated on the basis of the reconstructed coordinate system. The marker member is located on an imaginary curved surface having a concave shape toward the head and located on the frame. Thus, the marker member is located at angular position such that all portions of the marker member are equidistantly away from a center of magnetic field. Therefore the marker member can be located comparatively near the center. Since the nonuniformity ofthe magnetic field intensity is minimized at a position closer to the center, the marker image distortion is suppressed, thus reducing the positional deviation of the marker image. Therefore, the coordinate system can be accurately reconstructed on the image, and hence the coordinates of the surgical target can be accurately calculated.