Siemens Aktiengesellschaft

Siemens Akteingesellschaft

Guenter Schnur

Ralf Ladebeck

Georg Goertler

Claude Reymond

Pascal Sommer

A superconducting, actively shielded magnet has a first and second superconducting coil modules that generate a homogeneous magnetic field in a first direction in an operating volume of the magnet and that reduces the scatter magnetic field in an environment of the magnet. A third superconducting coil module is arranged in proximity to the first and second coil modules. The third coil module is fashioned to generate a compensation gradient field given occurrence of an interference gradient field in the environment so that the effect of the interference gradient field in the operating volume is reduced.

Superconducting, actively shielded magnet

A nuclear magnetic resonance tomograph or an imaging magnetic resonance apparatus ( ) has a magnet ( ) which is isolated in terms of vibration from a surrounding structure, in particular a building floor ( ), by an isolation system ( ). The isolation system ( ) has an actively controlled isolation module ( ) which is preferably designed to damp non-acoustic vibrations, in particular vibrations with a frequency of less than 50 Hz. According to a preferred embodiment, moreover, a passive isolation module ( ) with a vibration-damping material (D) is present. A particularly high degree of isolation of the magnet ( ) from the surrounding structure can be achieved with the aid of the isolation system ( ).

Magnetic resonance apparatus isolation system

In an image acquisition method in which there is a sensitivity characteristic over the image space that is non-uniform but that changes only slowly, this characteristic is determined according to the steps of, in the original image, intensity changes are limited to a predetermined maximum value, a low-pass filtering is applied to the auxiliary image acquired in this way, and the sensitivity characteristic of the image acquisition method over the image space is acquired from the low-pass-filtered auxiliary image.

Method for correcting the intensity of an image

Two MR magnetic field probes arranged in a centrally symmetrical fashion in relation to the magnetic field center, are attached in the examination area of the magnet. The output signals of the two MR magnetic field probes are supplied to a multiplying RF mixer, and a sum frequency signal is obtained from the output signal of the RF mixer, and the actual value of the basic field is determined from the frequency of this output signal.

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Hemhofen, Germany

Guenter Schnur