Design method of cylindrical shim coil

Abstract

The invention discloses a design method of a cylindrical shim coil. The method comprises the following steps: firstly, carrying out grid division on the cylindrical shim coil to obtain grid nodes; selecting a target point on the target spherical surface; establishing a finite difference relationship between a grid node current density flow function and grid node current density; setting the magnetic field intensity of a target point; establishing and solving an equation set between a grid node current density stream function and a target point magnetic field intensity z-axis direction component; and arranging equipotential lines distributed on the corresponding cylindrical surface of the coil at equal difference values to obtain a winding mode of the shim coil. The method is simple and effective, a new thought is provided for designing the cylindrical shimming coil, the designed cylindrical shim coil can effectively eliminate uneven magnetic field components of all orders of a main magnetic field of a cylindrical magnet system due to production and manufacturing errors, and then the uniformity of the main magnetic field of the cylindrical magnet system is improved.

Description

technical field [0001] The invention belongs to the technical field of magnetic resonance imaging coils, and in particular relates to a design method of a cylindrical shim coil. 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. [00...

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Problems solved by technology

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

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