Design method of flat-plate shimming coil

Abstract

The invention discloses a design method of a flat-plate shimming coil. The design method comprises the following steps: firstly, carrying out grid division on a circular plane of the coil; selecting a target point on the target spherical surface; establishing a finite difference relationship between a grid node current density flow function and the grid node current density; setting the magnetic field intensity of a target point; establishing an equation set between a grid node current density flow function and a target point magnetic field intensity axial direction component; constructing a power consumption and local uniform distribution combined constraint function, solving a constraint matrix, and solving a specific numerical value of a grid node current density stream function by using a Tikhonov regularization method; according to the equipotential lines distributed on the corresponding coil circular plane of the grid node current density flow function, carrying out equipotential value arrangement, and then obtaining the winding mode of the shimming coil. According to the invention, non-uniform magnetic field components of all orders of the main magnetic field of the flat-plate magnet system due to production and manufacturing errors can be effectively eliminated, so that the uniformity of the main magnetic field of the flat-plate magnet system is improved.

Description

technical field [0001] The invention relates to a design method of a planar shim coil applied to a planar magnet. Background technique [0002] According to different working principles and application fields, magnetic resonance instrument systems can be divided into nuclear magnetic resonance (NMR) instruments, magnetic resonance imaging (MRI) instruments, and electron paramagnetic resonance (EPR) instruments. Magnets are the most important components of magnetic resonance instrument systems. One of the components of the magnetic resonance instrument, the performance of the magnetic resonance instrument depends largely on the main magnetic field B of the magnet 0 The higher the uniformity of the main magnetic field of the magnet, the higher the signal-to-noise ratio and resolution of the NMR signal obtained by the NMR instrument, and the higher the quality of the MRI image obtained by the MRI instrument. [0003] Ideally, the main magnetic field strength of the MRI equipme...

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Problems solved by technology

[0004] In order to solve the problem of the inhomogeneity of the main magnetic field of the flat magnet system (such as: permanent magnet, conventional electromagnet, superconducting magnet, etc.), the patent of the present invention proposes a design method of a flat shim coil for magnetic resonance imaging. The shimming coil designed by this method can eliminate the inhomogeneous magnetic field components of each order of the main magnetic field of the flat-plate MRI magnet system, and improve the uniformity of the main magnetic field (such as figure 1 shown)

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