Reduction of RF field disturbance in magnetic resonance apparatus
First Claim
1. A magnetic resonance apparatus for examining a subject, comprising:
- a) a region in which the subject is positioned during examination;
b) radio frequency means for applying a radio frequency field having a frequency to the region for producing magnetic resonance in the subject; and
c) a transducer disposed in the region and having a lead which is grounded to signals having the frequency of said radio frequency field at a distance along the lead from the transducer which is equal to a quarter wavelength at said radio frequency field frequency or to an odd multiple thereof.
3 Assignments
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Accused Products
Abstract
In a magnetic resonance apparatus including a transducer (25, 31 ) positioned in the examination region of the apparatus, the transducer is connected with equipment (49) outside the examination region by way of a lead (47) which is grounded (51, 53) to signals of the frequency of the RF field applied to a subject (5) in the examination region to excite magnetic resonance in the subject, at a distance along the lead from the transducer equal to a quarter wavelength at the RF field frequency (or an odd multiple thereof). Distortion of the RF field due to loading by the transducer is thereby reduced. The transducer may, for example, be a microphone or loudspeaker, e.g. incorporated in an intercom or active noise reduction arrangement, or a sensor for sensing a condition of a patient being examined.
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Citations
13 Claims
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1. A magnetic resonance apparatus for examining a subject, comprising:
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a) a region in which the subject is positioned during examination; b) radio frequency means for applying a radio frequency field having a frequency to the region for producing magnetic resonance in the subject; and c) a transducer disposed in the region and having a lead which is grounded to signals having the frequency of said radio frequency field at a distance along the lead from the transducer which is equal to a quarter wavelength at said radio frequency field frequency or to an odd multiple thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification