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US 7,611,508 B2Granted
Floating sleeve microwave antenna for tumor ablation
AssigneeWisconsin Alumni Research Foundation
InventorsDeshan Yang, John Michael Bertram, Mark Christopher Converse, John Goodwin Webster, David Mahvi
Life of this patent
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Abstract
An antenna for microwave tumor ablation provides coaxial antenna conductors surrounded by an insulated sleeve of length and size promoting destructive interference of axial microwave energy passing inside and outside of the sleeve to limit the tail of SAR power toward the skin.
Claims16
A microwave ablation antenna comprising:
- a substantially non-helical coaxial antenna having a center conductor and an outer conductor extending along an axis to allow positioning of a proximal end of the coaxial antenna within a patient at a site of a tumor and a distal end of the coaxial antenna outside of a patient to be connected to a microwave source having a microwave frequency;
- and
- a sleeve outside and electrically insulated from the outer conductor and the center conductor, the sleeve extending along the axis to provide a relative phase shift between microwave energy traveling axially outside the outer conductor and within the sleeve, and microwave energy traveling axially outside the sleeve, the relative phase shift equal substantially to an odd multiple of one half a wavelength of the microwave frequency;
- whereby microwave energy distal to the sleeve is suppressed by destructive cancellation of the microwave energy at an exit of the sleeve.
1 more element
A method of treating a tumor comprising the steps of:
- (a) positioning a substantially non-helical coaxial antenna having a center conductor and an outer conductor extending along an axis with a proximal end of the coaxial antenna within a patient at a site of a tumor and a distal end of the coaxial antenna outside the patient;
- and
- (b) connecting the coaxial antenna to a microwave source having a microwave frequency;
- wherein the coaxial antenna includes a sleeve outside and electrically insulated from the outer conductor and the center conductor, the sleeve extending along the axis to provide a phase shift between microwave energy traveling axially outside the outer conductor and within the sleeve, and microwave energy traveling axially outside the sleeve of substantially an odd multiple of pi radians so as to cause destructive cancellation of the microwave energy at an axial exit of the sleeve between the energy traveling axially within the sleeve and energy traveling axially outside the sleeve.
1 more element
Dependencies are inferred from the claim text.