PROBLEM TO BE SOLVED: To provide an MRI system including a magnetic field gradient generation unit that can suppress deterioration of tomographic images while reducing a leakage magnetic field, is thinned, and has a minor axis thereof extended for use in a horizontal magnetic field type or has a radial direction dimension thereof reduced for use in a vertical magnetic field type.SOLUTION: A magnetic field gradient generation unit 3 of an MRI system includes at least a pair of conducting rings 5 disposed within an arrangement area outside magnetic field gradient generation sources 3a and 3b in a radial direction of a static magnetic field generation source on the sides of the ends of the magnetic field gradient generation unit 3 in a homogenous magnetic field direction inside the magnetic field gradient generation unit 3. A coil pattern 341b of at least one turn is located in the vicinity of the conducting rings 5 in a radial direction. On a section cut with a plane containing the radial direction and homogenous magnetic field direction (z-axis direction), a dimension in the radial direction of the coil pattern 341b is smaller than that of a coil pattern 342b of turns of the same coil other than the at least one turn, and a dimension in the homogeneous magnetic field direction is larger.COPYRIGHT: (C)2015,JPO&INPIT【課題】漏れ磁場を低減しつつ断層画像の劣化を抑制でき、且つ、薄肉化、並びに、水平磁場型の場合には短軸長化、垂直磁場型の場合には径方向寸法が縮小化された傾斜磁場発生装置を有するMRI装置を提供する。【解決手段】MRI装置の傾斜磁場発生装置3は、該傾斜磁場発生装置3の内部かつ均一磁場方向における傾斜磁場発生装置3の端部側かつ静磁場発生源の径方向における傾斜磁場発生源3a,3bの外側である配置領域に設けられた少なくとも一対の導体リング5を有する。また、導体リング5の径方向に近接して位置される少なくとも一ターンのコイルパターン341bが、径方向と均一磁場方向(z軸方向)とを含む平面で切断される断面内において、前記少なくとも一ターンと同一コイルの他のターンのコイルパターン342bよりも、径方向の寸法が小さく、均一磁場方向の寸法が大きい。【選択図】図3
