Design method of non-planar gradient coil
A gradient coil and design method technology, applied in the direction of measuring magnetic variables, measuring devices, instruments, etc., can solve problems such as large eddy currents, and achieve the effect of improving image quality
Inactive Publication Date: 2021-04-20
HUIREN WANGDU MEDICAL EQUIP SCI & TECH CO LTD
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[0003] In order to solve the problem of large eddy current generated by the flat gradient coil on the pole head of the above-mentioned open MRI magnet, the patent of the present invention proposes a design method of a non-planar gradient coil, which can reduce the eddy current generated by the gradient coil on the pole head and improve Image Quality of Open MRI Systems
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[0052] Embodiments of the present invention will be further described below in conjunction with the accompanying drawings.
[0053] Below is a design embodiment of the present invention, and its design flow chart is as follows figure 1 As shown, the design parameters of the non-planar gradient coils are set. The diameter of the non-planar gradient coils is 0.42m, and the distances are 460mm, 480mm and 500mm respectively. The sphere with a diameter of 360mm is divided into 16 layers, and a test is set every 11.6° points, a total of 496 target points, the error is not greater than 5%, the specific design steps are as follows.
[0054] Step 1: According to the design parameters of the non-planar gradient coil set above, use MATLAB software to model the circular surface and divide the triangular mesh, and sort the vertices and surfaces of the triangular mesh to obtain the source point coordinate S (x,y,z) and the face number connected to the vertex.
[0055]Step 2: Bending the p...
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The invention discloses a design method of a non-planar gradient coil, and the non-planar gradient coil designed by the invention is composed of two arc-shaped surfaces formed by bending two circular surfaces at a certain angle, and the method comprises the following steps of: firstly, dividing a target point on a sphere, and respectively calculating magnetic field values of the gradient coil on the target point by adopting a spherical harmonic function; then reading each vertex and each surface of a triangular mesh, optimizing the arrangement sequence of the vertexes and the surfaces, setting the sizes of wires according to a boundary element method, calculating contribution values of electrified wires in a source point region to field points, constraining the minimum power consumption and the minimum energy storage of the non-planar gradient coil, and solving the minimum power consumption and the minimum energy storage of the non-planar gradient coil; solving the current density distribution on the non-planar gradient coil, and finally acquiring the winding shape of the non-planar gradient coil through a flow function method. By the adoption of the design method of the non-planar gradient coil, the distance between the gradient coil and a pole head can be increased, vortexes generated by the gradient coil on the pole head are reduced, and the image quality of an open type MRI system is improved.
Description
technical field [0001] The invention relates to the field of designing magnetic resonance imaging system components, in particular to a method for designing non-planar gradient coils. Background technique [0002] Magnetic resonance imaging (Manetic Resonance Imaging MRI) technology is a technology that crosses multiple technologies, including electromagnetics, digital signal processing, biomedicine, and atomic physics. Compared with other medical imaging technologies, MRI has radiation-free, high-resolution Therefore, MRI technology has important clinical application value in medical examination. Due to the rapid shear of the gradient coil, eddy currents will be generated on the poles of the magnet, and the electromagnetic field generated by the eddy currents will be superimposed on the main magnetic field. The uniformity of the magnetic field reduces the image quality of MRI. Increasing the distance between the gradient coil and the pole head can effectively reduce the edd...
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IPC IPC(8): G01R33/385G01R33/421
Inventor 李良安田焕霞安学亮陈琳鑫
Owner HUIREN WANGDU MEDICAL EQUIP SCI & TECH CO LTD