Design method of the coil pattern gradient magnetic field coil, and nuclear magnetic resonance imaging apparatus

摘要

It is represented by current potential vector was assigned to the contact of the finite surface elements, the initial value of the current distribution of the current on the surface of the shield coil and primary coil, the magnetic field evaluation of the plurality of the set in at least one of the static magnetic field coil unit and the imaging region It is represented by the magnetic field vector, the point target magnetic field, and the response matrix to the magnetic field vector, in the singular value decomposition of the response matrix, get the singular values, and eigenvalues ​​group of the magnetic field distribution, the eigenvector group of current potential from current potential vector , expressed by a polynomial of the eigenvectors group of current potential, an approximation of the current potential vector is set as the difference target magnetic field the difference between the initial value of the magnetic field vector and the target magnetic field to generate a difference target magnetic field, the coefficient of each term of the polynomial It is determined based on eigenvectors group of the magnetic field distribution and the singular values. Thus, regardless of the cross-sectional shape of the cylindrical shield coil and primary coil, suppress the generation of eddy current is further error magnetic field, to provide a design method of the coil pattern which can improve the quality of the cross-sectional image.