Method for making a permanent magnet particularly for MRI scanners and a permanent magnet, particularly for MRI scanners made by said method

摘要

Method for making magnets for use in MRI scanners, which magnets are three-dimensional and have a tubular wall made of magnetized material, the tubular wall being composed of individual elements made of magnetized material.The invention provides the following steps:determining the modulus and direction of the magnetization of elements necessary for generating a predetermined magnetic field in the cavity inside said tubular wall in a theoretical two-dimensional magnet model,extruding the two-dimensional model to a three-dimensional model and at least partially compensating aberrations, distortions or inhomogeneites of the magnetic field generated in the three-dimensional model by modifying the magnetization orientation in the individual elements and in the plane of the two-dimensional model such to minimize differences between the magnetic field in the two-dimensional model and the magnetic field in the three-dimensional model.