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SELF SHIMMING MRI MAGNET

IP.com Disclosure Number: IPCOM000201283D
Publication Date: 2010-Nov-10
Document File: 9 page(s) / 391K

Publishing Venue

The IP.com Prior Art Database

Abstract

A superconducting magnet in an MRI or NMR system having self-shimming capability is disclosed. An embodiment of the proposed invention utilizes the existing main coil assembly to provide shimming capability with high sensitivity to correct or compensate unwanted axial harmonics of magnetic field. The invention eliminates the need of axial superconducting shim coils, thereby reducing the overall complexity, cost of material, manufacturing, and labor.

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SELF SHIMMING MRI MAGNET

FIELD OF INVENTION

The invention generally relates to a superconducting magnet in an MRI or NMR system and more particularly to a superconducting magnet in an MRI or NMR system with self- shimming capability.

BACKGROUND OF THE INVENTION

A conventional superconducting MRI magnet system comprises two parts to generate uniform magnetic field. One part of the superconducting MRI magnet is a main coil system that generates a main magnetic field. Another part of the superconducting MRI magnet is a superconducting shim coil system which is either a superconducting shim coil system or a passive shim system that corrects undesired field in-homogeneity. FIG. 1 illustrates the main coil system of a typical superconducting MRI magnet. FIG. 2 illustrates the superconducting shim coil system. FIG. 3 illustrates the superconducting main coils and shim coils assembly.

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FIG. 1

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FIG. 2

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FIG. 3

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Generally, assembly of superconducting shim coils incurs high cost. Further, main field low level drift remains a challenge in the conventional assembly. The main field low level drift is caused by defects in the magnet, for example, an imperfect superconducting joint, or a damaged superconducting wire. In the conventional superconducting magnet configuration as shown in figure 3, all the main coils are connected in series. As a result, same current flows through all the main coils and affects the main coil low level fields drift.

Therefore, there is...