Method and apparatus for determining probe location
First Claim
1. A method for determining a position of a surgical instrument, the method comprising the steps of:
- placing an electron spin resonance sample in a known position with respect to the surgical instrument;
placing the sample in the imaging region of a magnetic resonance imaging apparatus having a main magnetic field;
applying at least a first gradient magnetic field in the imaging region;
determining the resonant frequency of the sample in the presence of the at least a first gradient magnetic field; and
based on the resonant frequency of the sample, determining the position of the surgical instrument with respect to the at least a first gradient magnetic field.
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Accused Products
Abstract
A magnetic probe (1) for use with a magnetic resonance imaging apparatus comprises an electron spin resonance (ESR) magnetometer. The position of the probe (1) tracked by measuring the resonant frequency of an ESR sample (32) in the probe. The resonant frequency is measured in the presence of a gradient sequence which employs three orthogonal, linear gradients. By determining the resonant frequency of the ESR sample in the presence of each of the gradients, the position of the probe can be determined. The probe may be placed on or in an object, and the position of the probe may be displayed on a desired magnetic resonance image of the object.
198 Citations
27 Claims
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1. A method for determining a position of a surgical instrument, the method comprising the steps of:
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placing an electron spin resonance sample in a known position with respect to the surgical instrument; placing the sample in the imaging region of a magnetic resonance imaging apparatus having a main magnetic field; applying at least a first gradient magnetic field in the imaging region; determining the resonant frequency of the sample in the presence of the at least a first gradient magnetic field; and based on the resonant frequency of the sample, determining the position of the surgical instrument with respect to the at least a first gradient magnetic field. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A magnetic resonance apparatus comprising:
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means for producing a homogeneous magnetic field in an imaging region; a probe containing an electron spin resonance sample; means for producing gradient magnetic fields in the imaging region; means for determining the electron spin resonance frequency of the sample in the presence of at least one magnetic field gradient; and means for determining the position of the probe in relation to the at least one magnetic field gradient. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A device for determining a position of an instrument within the imaging region of a magnetic resonance imaging apparatus having a main magnetic field and capable of generating three orthogonal time varying gradient magnetic fields within the imaging region, the device comprising:
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a probe comprising an electron spin resonance sample, the probe capable of being placed in a known position in relation to the instrument; means for determining the resonant frequency of the sample in the presence of the gradient magnetic fields; and means for determining the position of the instrument when the sample is placed in the known position in relation to the instrument. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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24. A method for utilizing a surgical instrument having an electron spin resonance sample placed in a known position with respect thereto, the method comprising the steps of:
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placing the instrument at three locations within the imaging region of an MR imaging apparatus; while the instrument is placed at each of the three locations, applying at least a first gradient magnetic field in the imaging region and determining the resonant frequency of the sample in the presence of the at least a first gradient magnetic field; based on the resonant frequency of the sample at each of the three locations, determining the positions of the three locations; acquiring MR image data indicative of an object placed within the imaging region; and based on the determined positions, producing a desired image. - View Dependent Claims (25, 26, 27)
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Specification