公开(公告)号：EP0982598A2

公开(公告)日：2000-03-01

申请号：EP99306173.8

申请日：1999-08-03

申请人： PICKER INTERNATIONAL, INC.

发明人： McGinley, John V. M. ,  Young, Ian R. ,  Demeester, Gordon D. ,  Kinanen, Ilmari

IPC分类号： G01R33/38 ,  G01R33/387

CPC分类号： G01R33/383 ,  G01R33/3873

摘要： A pair of annular magnets (10) generate a vertical magnetic flux field through an imaging volume (12) . The flux is focussed by a pair of Rose rings (26) of high cobalt steel. A high order shim set includes a plurality of permanently magnetized or magnetized iron rings (32a, 32b, 32c, 32d) which cooperatively interact with the magnet assembly to optimize the homogeneity of the magnetic flux through the imaging volume. One of the permanent magnetic rings (32d) , is mounted with an opposite polarity relative to the others. The magnetized rings are mounted in a non-ferrous, electrically insulating support structure (34) such that gradient coils (50) can be positioned behind the permanent magnet rings. A flux return path (14, 16, 18, 20, 22, 24) provides a low flux resistant path from adjacent the Rose ring at one side of the imaging volume remotely around the imaging volume to a position adjacent the Rose ring at the other side of the imaging volume.

摘要翻译： 一对环形磁体（10）通过成像体积（12）产生垂直磁通场。 助焊剂由一对高钴钢的玫瑰环（26）聚焦。 高阶垫片包括多个永久磁化或磁化的铁环（32a，32b，32c，32d），其与磁体组件协作地相互作用以优化通过成像体积的磁通量的均匀性。 永久磁环（32d）中的一个相对于其它永久磁环安装有相反的极性。 磁化环安装在有铁，电绝缘的支撑结构（34）中，使得梯度线圈（50）可以位于永磁体环的后面。 磁通返回路径（14,16,18,20,22,24）在成像体积的远侧围绕成像体积的一侧的玫瑰环附近提供低阻抗路径，使其与另一方的玫瑰环相邻的位置 一侧的成像体积。