Radiation Applicator and Method of Radiating Tissue

Abstract

A dipole microwave applicator emits microwave radiation into tissue to be treated. The applicator is formed from a thin coax cable having an inner conductor surrounded by an insulator, which is surrounded by an outer conductor. A portion of the inner conductor extends beyond the insulator and the outer conductor. A ferrule at the end of the outer conductor has a step and a sleeve that surrounds a portion of the extended inner conductor. A tuning washer is attached to the end of the extended inner conductor. A dielectric tip encloses the tuning washer, the extended inner conductor, and the sleeve of the ferrule. The sleeve of the ferrule and the extended inner conductor operate as the two arms of the dipole microwave antenna. The tuning washer faces the step in the ferrule, and is sized and shaped to cooperate with the step in balancing and tuning the applicator.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]The present application is related to commonly owned copending International patent application no. WO 2006 / 002943, concerning a Radiation Applicator and Method of Radiating Tissue and which is hereby incorporated by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates generally to medical technology, and more specifically to microwave radiation applicators and methods of thermal ablative treatment of tissue using radiated microwaves.[0004]2. Background Information[0005]Thermal ablative therapies may be defined as techniques that intentionally decrease body tissue temperature (hypothermia) or intentionally increase body tissue temperature (hyperthermia) to temperatures required for cytotoxic effect, or to other therapeutic temperatures depending on the particular treatment. Microwave thermal ablation relies on the fact that microwaves form part of the electromagnetic spectr...

AI Technical Summary

Benefits of technology

"The present invention is a dipole microwave applicator for ablating tissue. It consists of an outer conductor, an inner conductor, a ferrule, and a dielectric tip. The microwave energy is emitted from the tip and the ferrule, which surrounds a portion of the inner conductor. A cooling fluid is introduced to absorb heat from the coaxial cable and prevent overheating. The microwave applicator can be inserted directly into tissue, such as a tumor, and the method includes supplying electromagnetic energy to the applicator to radiate electromagnetic energy into the tumor. The technical effects of this invention include higher power levels, distributed emission of microwave radiation, and improved cooling efficiency."

Problems solved by technology

According to the method, there can be performed an operation on liver cancer, which has been conventionally regarded as very difficult.

However, a drawback with the existing techniques include the fact that they are not optimally mechanically configured for insertion into, and perforation of, the human skin, for delivery to a zone of soft tissue to be treated.

Typically, known radiation applicator systems do not have the heightened physical rigidity that is desirable when employing such techniques.

In addition, some radiation applicators made available heretofore do not have radiation emitting elements for creating a microwave field pattern optimized for the treatment of soft tissue tumors.

Also, given the power levels employed in some applicators and treatments, there can be problems of unwanted burning of non-target, healthy tissue due to the very high temperatures reached by the applicator or the components attached thereto.

Further, although small diameter applicators are known, and liquid cooling techniques have been used, there has been difficulty in designing a small diameter device with sufficient cooling in applications employing power levels required to deal with soft tissue tumors.

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