Method for effectively correcting main magnetic field of magnetic resonance imaging system

Abstract

The invention discloses a method for effectively correcting a main magnetic field of a magnetic resonance imaging system. During a scanning process of the magnetic resonance imaging system, imaging space of the magnetic resonance imaging system is divided into two parts by a sickbed, one is the part above the sickbed, involved in the imaging scanning process, of the imaging space, and the other one is the part under the sickbed, separated from the imaging scanning, of the imaging space. When harmonic components shaped like a Chinese character 'tian' which are larger than the target uniformity of the main magnetic field of the system exist in the part, under the sickbed, of the imaging space of the magnetic resonance imaging system, shimming can be only conducted on the part above the sickbed, involved in the imaging scanning process, of the imaging space; shimming is conducted on the whole imaging space of the magnetic resonance imaging system otherwise. According to the method for effectively correcting the main magnetic field of the magnetic resonance imaging system, a standard shimming hardware system is not changed, and the method for effectively correcting the main magnetic field of the magnetic resonance imaging system is applicable to the vast majority of the magnetic resonance imaging systems for human body imaging.

Description

technical field [0001] The invention relates to a method for effectively correcting the main magnetic field of a magnetic resonance imaging system. Background technique [0002] The main magnetic field of the imaging space (also called diameter of the special volume, DSV) of the magnetic resonance imaging (Magnetic Resonance Imaging, MRI) system needs to meet the requirement of near perfect uniformity (a change of a few millionths, parts per million (ppm, 10 -6 ,millionth)). The generation of a highly uniform and strong magnetic field in the imaging space of the magnetic resonance imaging system often requires the use of superconducting (superconducting, SC) technology. A theoretical superconducting magnet design can provide an ideal high-quality magnetic field environment in the imaging space of an MRI system. However, in the manufacturing process of MRI superconducting magnets, some unavoidable production errors will cause the inhomogeneity of the magnetic field (usuall...

AI Technical Summary

Problems solved by technology

Passive shimming itself has a high complexity because the number of sampling points in the shimming film and imaging space reaches as many as hundreds, and it is a pathological problem.

Under the action of the main magnetic field, the shimming sheet is magnetized to generate a magnetic field for shimming, and at the same time, it will also generate eddy current effects, which will affect the result of shimming

In the practice of MRI passive shimming, in order to find an acceptable result, the shimming process usually has to be repeated many times, which makes shimming a very time-consuming task in the MRI engineering process

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