Shimming method and device, electronic device, and storage medium

Patent metadata

Field	Value
Publication number	US-2023152400-A1
Application number	US-202217992868-A
Country	US
Kind code	A1
Filing date	Nov 22, 2022
Priority date	Nov 16, 2021
Publication date	May 18, 2023
Grant date	—

Abstract

A shimming method and device, an electronic device, and a storage medium are disclosed. The shimming method includes: obtaining object static magnetic field distribution information corresponding to a target object, the object static magnetic field distribution information including the static magnetic field distribution information of the target object under the action of a main magnet of a magnetic resonance system; determining a target static magnetic field based on the object static magnetic field distribution information and a preset shim coil magnetic field distribution model; and adjusting at least one shim coil parameter in the shim coil magnetic field distribution model until a magnetic field uniformity of the target static magnetic field satisfies a preset condition, and accordingly obtaining at least one target shim coil parameter.

First claim

What is claimed is:

1 . A shimming method, comprising:
obtaining object static magnetic field distribution information corresponding to a target object, wherein the object static magnetic field distribution information comprises static magnetic field distribution information of the target object under the action of a main magnet of a magnetic resonance system; determining a target static magnetic field based on the object static magnetic field distribution information and a preset shim coil magnetic field distribution model; and adjusting at least one shim coil parameter in the preset shim coil magnetic field distribution model until a magnetic field uniformity of the target static magnetic field satisfies a preset condition, and accordingly obtaining at least one target shim coil parameter.

2 . The shimming method as recited in claim 1 , wherein the at least one shim coil parameter comprises one or more selected from the group consisting of: a number of channel, a size, a spatial position, a current magnitude, and a number of turns of at least one shim coil.

3 . The shimming method as recited in claim 1 , further comprising the following operation prior to obtaining the object static magnetic field distribution information corresponding to the target object:
determining the magnetic field distribution information of the shim coil magnetic field distribution model according to Bio-Savart law.

4 . The shimming method as recited in claim 1 , wherein obtaining the object static magnetic field distribution information corresponding to the target object comprises:
obtaining object static magnetic field distribution information corresponding to each of a number of n target objects, n being a positive integer greater than 1; and wherein accordingly, determining the target static magnetic field based on the object static magnetic field distribution information and the preset shim coil magnetic field distribution model comprises: determining the target static magnetic field based on the respective object static magnetic field distribution information corresponding to each of the n target objects and the preset shim coil magnetic field distribution model.

5 . The shimming method as recited in claim 4 , wherein the shim coil magnetic field distribution model comprises shim coil units of a number of in channels, m being a positive integer greater than 1, wherein determining the target static magnetic field based on the respective object static magnetic field distribution information corresponding to each of the n target objects and the preset shim coil magnetic field distribution model comprises:
determining the target static magnetic field using an objective function

F
=

∑

i
=
1

n

∑

j
=
1

m

(

C
j

⁢

b
j

+

B
i

)

;

where F represents the magnetic field distribution information of the target static magnetic field, C j represents a current magnitude of a shim coil unit of a j-th channel in the shim coil magnetic field distribution model, b j represents the magnetic field distribution information of a shim coil unit of a j-th channel in the shim coil magnetic field distribution model, and B i represents the object static magnetic field distribution information of an i-th target object.

6 . The shimming method as recited in claim 5 , wherein adjusting the at least one shim coil parameter in the shim coil magnetic field distribution model until the magnetic field uniformity of the target static magnetic field satisfies the preset condition, and accordingly obtaining the at least one target shim coil parameter comprises:
adjusting the at least one shim coil parameter in the shim coil magnetic field distribution model according to a particle swarm algorithm and the objective function, until a standard deviation of a magnetic field distribution of the target static magnetic field is less than a preset threshold or until a number of iterations of the particle swarm algorithm reaches a preset number, thus obtain the at least one target shim coil parameter.

7 . The shimming method as recited in claim 6 ; wherein adjusting the at least one shim coil parameter in the shim coil magnetic field distribution model according to the particle swarm algorithm and the objective function until the standard deviation of the magnetic field distribution of the target static magnetic field is less than the preset threshold or until the number of iterations of the particle swarm algorithm reaches the preset number thus obtaining the at least one target shim coil parameter comprises:
for each of a plurality of shim coil magnetic field distribution models with different numbers of channels, adjusting at least one sub-shim coil parameter in the shim coil magnetic field distribution model according to the particle swarm algorithm and the objective function, until the number of iterations of the particle swarm algorithm reaches the preset number of times to obtain at least one sub-target shim coil parameter corresponding to each of the plurality of shim coil magnetic field distribution models; determining a standard deviation of a magnetic field distribution of the target static magnetic field corresponding to each of the plurality of shim coil magnetic field distribution models based on the respective at least one sub-target shim coil parameter corresponding to each of the plurality of shim coil magnetic field distribution models and the objective function; and taking the shim coil magnetic field distribution model with a minimum standard deviation of the magnetic field distribution of the target static magnetic field as the target shim coil magnetic field distribution model, and using the number of channels and the at least one sub-target shim coil parameter of the target shim coil magnetic field distribution model as the at least one target shim coil parameter.

8 . An electronic device; comprising a memory, a processor, and a computer program stored in the memory and executable by the processor; wherein when the processor executes the computer program, the electronic device is caused to perform a shimming method comprising the following operations:
obtaining object static magnetic field distribution information corresponding to a target object, wherein the object static magnetic field distribution information comprises static magnetic field distribution information of the target object under the action of a main magnet of a magnetic resonance system; determining a target static magnetic field based on the object static magnetic field distribution

Assignees

• Shenzhen Inst Of Adv Tech Cas

Inventors

• Zheng Hairong
• Chen Qiaoyan
• Li Ye
• Luo Chao
• Liu Xin

Classifications

• G01R33/3875 Primary

  using correction coil assemblies, e.g. active shimming · CPC title

• G01R33/56536

  due to magnetic susceptibility variations · CPC title

• A61B5/055

  involving electronic [EMR] or nuclear [NMR] magnetic resonance, e.g. magnetic resonance imaging · CPC title

• A61B5/0042

  for the brain · CPC title

• A61B2503/40

  Animals · CPC title