US 7,002,347 B2Granted

Local coil unit for a magnetic resonance apparatus

AssigneeSiemens Aktiengesellschaft

InventorsThorsten Feiweier, Razvan Lazar, Wolfgang Renz, Lothar Schön

Life of this patent

Estimating the term…

Loading patent…

Abstract

A local coil unit for a magnetic resonance apparatus, which radiates a radio-frequency field into an examination subject, has a housing and at least a part of the housing is formed of an insulating dielectric material that passively compensates for an inhomogeneity in the high-frequency field in the subject. The material has a relative dielectric value εr of greater than 50, preferably greater than 100, and a dielectric loss factor tan δ of less than 2.5×10−2, preferably less than 1×10−3. In the dielectric material displacement currents are generated which create an additional magnetic field that compensates for the minima in the B1 field as a result of the eddy currents arising in the patient due to the radio-frequency radiation.

Claims14

Dependent claims

A local coil unit for a magnetic resonance apparatus comprising:

a resonator for generating a radio frequency electromagnetic field, said resonator being adapted to radiate said radio frequency electromagnetic field into an examination subject that causes an inhomogeneity in said radio frequency electromagnetic field in the examination subject by eddy current generation;
and
a housing in which said resonator is disposed, at least a part of said housing being comprised of an insulating, dielectric material having a high relative dielectric value εr greater than 50, for compensating said inhomogeneity, said part of said housing encompassing a surface area in a range between 100 cm2 to 300 cm2 corresponding to an extent of said eddy current, said part of said housing being disposed in a region of said housing adapted for contact with said examination subject.

Dependencies are inferred from the claim text.