Patent ID: 8509873

Claim:
A medical device comprising: a transducer configured to generate high intensity focused ultrasound for a treatment of a subject by elevating a temperature of tissue in the subject, said transducer being comprised of material that produces a susceptibility difference between said transducer and an environment of said transducer; a magnetic resonance apparatus configured to generate magnetic resonance exposures that represent the temperature of said tissue during said treatment, said magnetic resonance apparatus being configured to generate a magnetic field that participates in generation of said magnetic resonance exposures, and said susceptibility difference causing a disruption of said magnetic field that produces an error in the temperature representation in magnetic resonance exposures; and a shim element having a material composition that gives the shim element a shimming effect, with said shim effect being located at a location relative to said transducer that causes said shimming effect of said shim element to counteract said susceptibility difference and reduce said disruption of said magnetic field and said error in said temperature representation in said magnetic resonance exposures.