Koninklijke Philips Corporation N.v.

Martijn Krelis Termeer

Jan Konijn

Johannes Adrianus Overweg

Cornelis Leonardus Gerardus Ham

Gerardus Bernardus Jozef Mulder

Theo Jenneskens

Guus Van Hest

Augustinus Bertus Petrus Van Hest

A shielded gradient coil assembly () to generate a gradient magnetic field, the assembly comprises on a plurality of radially inner and outer coaxial cylindrical surfaces a gradient field coil arrangement on the radially inner cylindrical surfaces including a longitudinal gradient field coil system () having one or more axial circumferential electrically conducting hollow z-field windings having a smaller transverse cross-section and a transverse gradient field coil system () having hollow (x,y)—field electrical conductors having a smaller transverse cross-section and arranged as saddle coils on the surfaces of the inner cylindrical surfaces. A gradient shield coil arrangement is provided on the radially outer cylindrical surfaces including a longitudinal gradient shield coil system () having one or more axial circumferential electrically conducting hollow z-shield windings having a larger transverse cross-section and a transverse gradient shield coil system () having solid electrical conductors arranged as saddle coils on the surfaces of the outer cylindrical surfaces. In this way an optimum combination is achieved of efficient direct and indirect cooling of the conductors while keeping eddy current effects at a low level.

Shielded gradient assembly

A gradient coil assembly for a magnetic resonance imaging system () includes at least one gradient coil () and a cooling arangement for cooling the gradient coil (). The gradient coil () includes a solid electrical conductor material forming one or more conductor lines () which are in direct contact with each other. The cooling arrangement includes a cooling channel () for guiding a cooling fluid (). The cooling channel () is arranged outside along the one or more conductor lines () in such a way that in a cross-sectional view one single continuous interface line between the cooling channel () and the one or more conductor lines () is formed. In this way efficient cooling of the gradient coil () may be achieved.

Cooling a gradient coil of a magnetic resonance imaging system

A control unit () operates a gradient coil device of a magnetic resonance imaging system (). At least one first parameter of the gradient coil device () and/or at least one second parameter of the gradient coil device () is provided. A damage calculation of an operation of the gradient coil device () is performed by use of a mathematical model (), which model () is based on the stress-cycle curve or a modified stress-cycle curve and uses the at least one first parameter () and/or the at least one second parameter (). Second parameters for further operation of said gradient coil device () are determined.

Method and control unit for operating a gradient coil device of an MRI system or another periodically stressed device

A magnetic resonance (MR) imaging apparatus comprises an MR imaging device () including a magnet () and heat generating components (). A cooling system () cools the heat generating components using chilled water from an air-cool chiller (). Sensors (TS, VS) are configured to measure thermal parameters of the heat generating components or of the cooling system. An MR controller () controls the MR imaging device to execute an MR imaging examination program ('exam card') () and to adjust the execution of the MR imaging examination program in response to a thermal parameter measured by the one or more sensors indicating the cooling system has insufficient cooling capacity. The MR controller may also adjust the exam card prior to its execution if the cooling system () has insufficient cooling capacity at the current air temperature to dissipate the heat load as estimated by a power dissipation model ().

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Poppel, Belgium

Martijn Krelis Termeer