Tissue ablation apparatus and method

Abstract

A method and apparatus for carrying our thermal ablation of target tissue is disclosed. The apparatus includes an RF ablation device having a multi-electrode electrode assembly designed to be deployed in target tissue, defining a selected-volume tissue region to be ablated, and having infusion channels for infusing a liquid into the target tissue during the ablation process. A control unit in the apparatus is operably connected to an RF energy source, for controlling the RF power level supplied to the electrodes, and to an infusion device, for controlling the rate of infusion of a liquid through the device into the tissue. During both electrode deployment and tissue ablation, impedance and or temperature measurements made within the tissue are used to control the RF source and infusion device, for optimizing the time and extent of tissue ablation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a continuation application claiming the benefit of U.S. application Ser. No. 10 / 260,187 filed Sep. 28, 2002, which claims the benefit of U.S. Provisional Application No. 60 / 326,043 filed Sep. 28, 2001; all related applications are incorporated herewith by reference in their entirety.FIELD OF THE INVENTION[0002]This invention relates generally to a method for treating tissue using minimally invasive methods. More particularly, the invention relates to an apparatus and method for ablatively treating tumorous and diseased tissue. Still more particularly, the invention relates to an apparatus and method for ablatively treating tumorous tissue using impedance values to control and optimize the delivery of electromagnetic ablative energy to a target tissue site.BACKGROUND OF THE INVENTION[0003]Various ablative therapies such as radio-frequency, microwave and laser ablation can be used to treat benign and cancerous tumors. In theory, suc...

AI Technical Summary

Benefits of technology

The invention provides an impedance controlled tissue ablation apparatus and method that uses localized impedance determination to optimize the delivery of radio-frequency or other electromagnetic energy to a target tissue site and create larger ablation volumes using lower power levels and faster ablation times than conventional methods. The apparatus includes an elongated delivery device with a plurality of resilient members that can be positioned at a selected tissue site and the impedance array can be used to control the delivery of ablative energy or therapy to the tumor volume. The method can also include detecting and treating tumors using multi-path impedance determination to monitor the progress of the ablation and control the delivery of energy or other therapy. The apparatus and method can provide greater sensitivity, predictive power, and faster ablation times than conventional methods.

Problems solved by technology

However in practice, there are numerous difficulties in the use of ablative procedures to treat cancerous tissue, these include (i) locating the target tissue, (ii) identifying or biopsying the disease state of the tumorous tissue (iii) distinguishing between diseased tissue versus healthy tissue, (iii) placing and maintaining the position of the ablation apparatus within the target tissue site, (iv) monitoring the progress of ablation including the developing ablation volume, (v) minimizing injury to adjacent critical structures (vi) assuring complete ablation of the tumor mass including assurance of a sufficient healthy tissue margin and (vii) assessing degree of the completed ablation.

Current ablative therapies have not considered nor provided solutions to these problems.

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