Patent ID: 6191584
Filing Date: 2001-02-20
Classification: G01R

Abstract:
A permanent magnet for nuclear magnetic resonance image detection, which magnet comprises:a magnetic structure having a yoke and magnetic poles, so shaped as to delimit or enclose a cavity, at least a part of a volume of the cavity forms a compartment for receiving at least a part of a body under examination, and at least a part of the volume of the cavity is permeated by a static magnetic field having specific intensity and homogeneity characteristics;the magnetic structure has at least one open side, parallel to the static magnetic field;the magnetic structure has at least two opposite main poles, lying face to face, transverse to the open side, the static magnetic field being generated therebetween;in the vicinity of the open side, the magnet has means for correcting the static magnetic field generated between the main poles, the correction means including means for increasing the magnetic potential near the open side, and over a predetermined depth therefrom, transverse to the open side, without reducing the span of the opening;the correcting means including, at the open side, a pair of opposite auxiliary poles, inwardly penetrating over a predetermined distance towards their respective main poles, which auxiliary poles are provided with magnetized material;wherein the main poles and the auxiliary poles have parallel magnetization vectors, oriented in the same direction.