公开(公告)号：EP0120927A4

公开(公告)日：1986-07-08

申请号：EP83903331

申请日：1983-09-23

申请人： NEW ENGLAND NUCLEAR CORP

发明人： LEE DENNY L Y ,  HAY ROBERT DUNCAN

IPC分类号： G01R33/48 ,  A61B5/055 ,  G01R33/383 ,  G01R33/387 ,  H01F7/02 ,  G01R33/08

CPC分类号： G01R33/383 ,  Y10S505/844

摘要： An NMR imaging apparatus (10) having a desired imaging volume for imaging of biological tissue, said apparatus comprising bias means (20) for generating a bias field, means for generating gradient fields, and radio frequency means for applying a pulse of electromagnetic radiation to the biological tissue and for detecting the resultant signals emitted from said tissue; wherein said bias means comprises a plurality of dipole ring magnets, (20) each dipole ring magnet comprising a plurality of segments, (22) each segment comprising an oriented, anisotropic permanent magnet material (23) arranged in a ring so that there is a substantially continuous ring of permanent magnet material; wherein the inner radius of at least one dipole ring magnet is different from the inner radius of an adjacent dipole ring magnet.