A multi-channel shim current source for magnetic resonance imaging and its operating method
A technology of magnetic resonance imaging and shimming current, applied in the direction of measuring magnetic variables, measuring devices, instruments, etc., to achieve the effect of improving current output capability, increasing reliability, improving accuracy and reliability
Active Publication Date: 2019-11-26
SHANGHAI JIAOTONG UNIV
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Problems solved by technology
[0005] In view of the above-mentioned defects in the prior art, the technical problem to be solved by the present invention is how to flexibly generate highly complex magnetic field distribution through system-level design
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[0033] A preferred embodiment of the multi-channel shimming current source for magnetic resonance imaging of the present invention includes a constant current source current module, a digital-to-analog conversion module, a current sensor module and a controller module, wherein the single-chip microcomputer passes The SPI bus is connected to the digital-to-analog converter, the digital-to-analog converter is connected to the constant current source current module, the constant current source current module is connected to the current sensor module, and the current sensor module is connected to the I2C bus Connect with the microcontroller. The constant current source current module includes an operational amplifier, a triode and a protection capacitor.
[0034] The circuit structure of the constant current source current module is: the positive input terminal of the operational amplifier is connected with resistor R1 (10KΩ) and resistor R2 (100KΩ), the negative input terminal of...
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The present invention discloses a multi-path shimming current source for magnetic resonance imaging and an operation method thereof, and relates to the magnetic resonance imaging field. The source comprises a constant-current source current module, a digital-to-analogue conversion module, a current sensor module and a controller module, a controller is connected with a digital-to-analogue converter through an SPI bus, the digital-to-analogue converter is connected with the constant-current source current module, the constant-current source current module is connected with the current sensor module, and the current sensor is connected with the controller through an I2C bus. A large-power Darlington tube is employed to extend the output capacity of operation and amplifier, different power sources are used by the output grades of the operation amplifier and the main power to allow the application of the system to be more flexible, and in the condition of facing the inductance load and being equivalent to very low series resistance value, the power-grade power supply voltage is properly reduced to substantially reduce the pressure of the Darlington tube. Each current source module is provided with a current sensor chip for current monitoring so as to perform feedback correction of current errors through PID control and reach the shimming purpose.
Description
technical field [0001] The invention relates to the field of magnetic resonance imaging, in particular to a multi-channel shimming current source for magnetic resonance imaging. Background technique [0002] Magnetic resonance shimming technology aims to eliminate the inhomogeneity of the magnetic field, which is of great significance to improve the imaging quality. Active shimming technology is to install shim coils in the working cavity of the magnet. The shim coils are composed of several copper coil arrays, which are regularly distributed on the surface of the cylindrical shim coil support. These coils have different sizes, shapes, and positions, and need to be powered by corresponding external constant current sources to generate the required correction magnetic field. The power supply mode of the shim coils in the prior art is that a single coil corresponds to a single power supply, so multiple shim coils need multiple independent current sources for power supply. ...
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IPC IPC(8): G01R33/389
CPCG01R33/389
Inventor 杜一平张娄重
Owner SHANGHAI JIAOTONG UNIV