Magnetic resonance apparatus
First Claim
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1. A magnetic resonance apparatus for examining a patient, comprising:
- a magnet means for producing a magnetic field in a region in which the patient is positioned during an examination, and for generating noise heard by the patient during the examination as a result of operation of said magnet means; and
an active noise reduction means for reducing the noise heard by the patient, including at least one first transducer in said region, and a source of electrical signals including at least one second transducer in said region, for supplying to said at least one first transducer an electrical signal to cause said at least one first transducer to produce in said region sound waves which reduce the noise heard by the patient during the examination as a result of the operation of said magnet means, said transducers being non-magnetic transducers, said at least one first transducer being a piezoelectric loudspeaker including a film of piezoelectric plastics material having two main surfaces, and carrying an electrode on each main surface, and being supported within an enclosure in a domed shape.
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Abstract
In a magnetic resonance apparatus including an active noise reduction arrangement (9, 49, 51, 53) for use by a patient (5) undergoing examination in the apparatus the transducers (25, 31) of the arrangement are non-magnetic, e.g. are of the electret, piezoelectric or condenser type, and have no parts of ferromagnetic material.
42 Citations
12 Claims
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1. A magnetic resonance apparatus for examining a patient, comprising:
- a magnet means for producing a magnetic field in a region in which the patient is positioned during an examination, and for generating noise heard by the patient during the examination as a result of operation of said magnet means; and
an active noise reduction means for reducing the noise heard by the patient, including at least one first transducer in said region, and a source of electrical signals including at least one second transducer in said region, for supplying to said at least one first transducer an electrical signal to cause said at least one first transducer to produce in said region sound waves which reduce the noise heard by the patient during the examination as a result of the operation of said magnet means, said transducers being non-magnetic transducers, said at least one first transducer being a piezoelectric loudspeaker including a film of piezoelectric plastics material having two main surfaces, and carrying an electrode on each main surface, and being supported within an enclosure in a domed shape. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
- a magnet means for producing a magnetic field in a region in which the patient is positioned during an examination, and for generating noise heard by the patient during the examination as a result of operation of said magnet means; and
Specification