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MAGNETIC RESONANCE GRADIENT COIL DESIGN FOR IMPROVED THERMAL MANAGEMENT

IP.com Disclosure Number: IPCOM000212765D
Publication Date: 2011-Nov-28
Document File: 4 page(s) / 42K

Publishing Venue

The IP.com Prior Art Database

Abstract

An MR gradient coil design that efficiently removes excessive heat is provided. The MR gradient coil design, described herein uses highly thermally conductive substrate such as Aluminum Nitride. The highly thermally conductive substrate is placed underneath the primary and/or secondary coils of the MR gradient coil system. Use of highly thermally conductive substrate lowers cooling requirements resulting in a thinner gradient coil former and improved gradient coil performance.

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MAGNETIC RESONANCE GRADIENT COIL DESIGN FOR IMPROVED THERMAL MANAGEMENT

FIELD OF INVENTION

The invention generally relates to magnetic resonance (MR) gradient coils and more particularly to an MR gradient coil design that provides efficient heat removal.

BACKGROUND OF THE INVENTION

Generally, magnetic resonance (MR) imaging systems use current carrying coils to produce magnetic field gradient. However, considerable amount of heat is produced inside the gradient coils (GC) assembly due to electrical losses in the gradient coils, such as x, y and z coils (primary and secondary), when the GC is pulsing. Extended pulsing of the GC may lead to highly elevated temperatures under the individual coils comprising the GC system. The heat generated by the GC needs to be dissipated essentially, as it can cause multiple issues in the operation of the MR imaging system.

The heat may cause impermissible stress on the patient and melting of casting resin molding material used in the gradient coil system leading to dangerous changes in the mechanical and electrical characteristics of the  MRI system.

Conventionally, heat dissipation systems include hollow electrical lines, through which a cooling agent flows or two layers of two tightly wound cooling conduits made of metal or polyamide. However, often poor conductivity of conduit material used causes less than optimal cooling and loss of pressure in the lines and leakages. Further, due to the sealed structure of the GC systems, leaking sections can be removed only with great difficulty or not at all, which is disadvantageous.

Hence there exists a need for a means of thermal management of MR gradient coils that allows efficient removal of heat.

BRIEF DESCRIPTION OF THE INVENTION

An MR gradient coil design that provides efficient heat removal is provided. The MR gradient coil design uses highly thermally conductive substrate to remove the excessive heat. According to the MR gradient coil design described herein, the highly thermally conductive substrate is placed underneath the primary and/or secondary coils.

DETAILED DESCRIPTION OF THE INVENTION

An MR gradient coil (GC) design that efficiently removes heat generated by the current flowing through various GC components is provided. The GC design helps dissipate heat from regions of the GC that may be damaged due to excessive heat.  Heat is removed by using a highly thermally conductive, to the order of ~200 W/m/K, polished substrate (HTCS) underneath GC components. HTCS removes heat very efficiently from the heat sources keeping the GC surface relatively cool. The HTCS used, ideally, has high electrical resistivity, to the order of >1014 ohm-cm, and high diele...