Magnetic flux density measurement in magnetic resonance electrical impedance tomography using a low-noise current source

The independent directional magnetic field measurement is a new technique for magnetic flux density measurement with high accuracy. This technique can reduce the limitation in term of angle that magnetic flux lines interact with Hall sensors. However, the original system limits the uniformity and symmetry of magnetic field patterns, which can cause an error for measurement system. Therefore, the aim of this research is to present the method to increase measurement accuracy of system, by improve magnetic field uniformity which can be done by using electromagnet instead of permanent magnet. The system is also improved the mechanical circle motion by using stepping motor, it is used to rotate Hall sensors in magnetic field which is generated by electromagnet. The result from experiment has shown of this method that can reduce the error percentage as 5% compare with original system. This method is shown 0.99997 of coefficient of determination, which represents to accuracy in magnetic flux density measurement range 0-1350 Gauss.

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Current Density Imaging Using Directly Measured HarmonicBzData in MREIT

Computational and Mathematical Methods in Medicine ◽

10.1155/2013/381507 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Chunjae Park ◽

Oh In Kwon

Keyword(s):

Magnetic Resonance ◽

Magnetic Flux ◽

Flux Density ◽

Current Density ◽

Background Field ◽

Magnetic Flux Density ◽

Reconstruction Procedure ◽

Phantom Experiment ◽

Impedance Tomography ◽

Space Data

Magnetic resonance electrical impedance tomography (MREIT) measures magnetic flux density signals through the use of a magnetic resonance imaging (MRI) in order to visualize the internal conductivity and/or current density. Understanding the reconstruction procedure for the internal current density, we directly measure the second derivative ofBzdata from the measuredk-space data, from which we can avoid a tedious phase unwrapping to obtain the phase signal ofBz. We determine optimal weighting factors to combine the derivatives of magnetic flux density data,∇2Bz, measured using the multi-echo train. The proposed method reconstructs the internal current density using the relationships between the induced internal current and the measured∇2Bzdata. Results from a phantom experiment demonstrate that the proposed method reduces the scanning time and provides the internal current density, while suppressing the background field inhomogeneity. To implement the real experiment, we use a phantom with a saline solution including a balloon, which excludes other artifacts by any concentration gradient in the phantom.

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Estimation of electrical conductivity distribution within the human head from magnetic flux density measurement

Physics in Medicine and Biology ◽

10.1088/0031-9155/50/11/016 ◽

2005 ◽

Vol 50 (11) ◽

pp. 2675-2687 ◽

Cited By ~ 44

Author(s):

Nuo Gao ◽

S A Zhu ◽

Bin He

Keyword(s):

Electrical Conductivity ◽

Magnetic Flux ◽

Flux Density ◽

Density Measurement ◽

Human Head ◽

Magnetic Flux Density ◽

Conductivity Distribution ◽

Flux Density Measurement

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Magnetic Flux Density Measurement Platform for an Inductive Wireless Power Transmitter Coil Design

Sensors ◽

10.3390/s22020479 ◽

2022 ◽

Vol 22 (2) ◽

pp. 479

Author(s):

Nataša Prosen ◽

Miro Milanovič ◽

Jure Domajnko

Keyword(s):

Magnetic Flux ◽

Flux Density ◽

Density Measurement ◽

Wireless Power Transfer ◽

Magnetic Flux Density ◽

Power Transfer ◽

Wireless Power ◽

Search Coil ◽

Transmitter Coil ◽

Flux Density Measurement

This paper presents a platform developed for automated magnetic flux density measurement. The platform was designed to be used to measure the magnetic flux density of the transmitter/receiver coil of an inductive wireless power transfer system. The magnetic flux density of a transmitter was measured using a small, 3-axis search coil. The search coil was positioned in the 3D space above the transmitter coil using a 3D positioning mechanism and used to measure the magnetic flux density at a specific point. The data was then sent to a computer application to visualize the magnetic flux density. The measured magnetic field could be used in combination with electromagnetic field solvers to design and optimize transmitter coils for inductive wireless power transfer systems.

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