Shimming method and device for a magnetic resonance system
A magnetic resonance and magnetic field technology, applied in measuring devices, measuring magnetic variables, instruments, etc., can solve the problems of low precision, poor magnetic field uniformity, large errors, etc., to reduce labor costs, reduce errors, and improve the shimming effect. Effect
Active Publication Date: 2021-12-28
上海尚磁机电科技有限公司
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It can be seen that the essence of the existing active shimming method is to obtain the harmonic components of each order of the main magnetic field through the uniform region magnetic field, and solving the magnetic field regression equation is an electromagnetic field inverse problem, and the harmonic components of each order of the shimming current obtained by solving The error is large and the accuracy is low, resulting in poor uniformity of the magnetic field after shimming
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[0049] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings but not all structures.
[0050] An embodiment of the present invention provides a shimming method for a magnetic resonance system. The method can be applied to magnetic resonance systems with shim coils. In the magnetic resonance system, by applying a shim current to the shim coil, the harmonic component magnetic fields of each order generated by the shim coil are superimposed on the main magnetic field, thereby canceling the harmonic components of each order in the uniform region. The method can be executed by a shimming device of the m...
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The invention discloses a shimming method for a magnetic resonance system. The shimming method includes: collecting the magnetic field strength before shimming at multiple sampling points in the uniform area; obtaining the unit current magnetic field contribution of shim coils at each order; The magnetic field intensity before the field and the unit current magnetic field contribution of each order shim coil determine the theoretical shim magnetic field distribution; construct a linear programming model and obtain the shim current of each order shim coil. The invention adopts a linear programming model for shimming, without constructing a magnetic field regression equation, and solves the problems of large shimming current error and poor magnetic field uniformity obtained by the existing active shimming method of constructing a magnetic field regression equation, and achieves shimming current The effect of smaller deviation and better uniformity of the magnetic resonance system.
Description
technical field [0001] Embodiments of the present invention relate to the technical field of magnetic field processing, and in particular to a method and device for shimming a magnetic resonance system. Background technique [0002] In the magnetic resonance system, the uniformity of the magnetic field is an important index. During the manufacturing process of magnetic resonance equipment, it will inevitably be affected by factors such as assembly errors and temperature, making the actual magnetic field uniformity of the magnetic resonance system 1 to 2 orders of magnitude worse than the designed uniformity. Therefore, in the actual application of the magnetic resonance equipment, in order to make the magnetic field of the magnetic resonance system meet the requirements of use, it is necessary to use an additional shimming method to correct the magnetic field in the homogeneous region. [0003] In the prior art, shimming methods for magnetic resonance systems include active...
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IPC IPC(8): G01R33/387
CPCG01R33/387
Inventor 汤洪明
Owner 上海尚磁机电科技有限公司