Tissue ablation apparatus and method

Abstract

A method and apparatus for controlling the extent of tissue ablation are disclosed. The method utilizes delivering energy from an energy deliver device to a plurality of deployed electrodes and regulating energy delivered to the electrodes based on the temperature sensed by at least one remote elongate sensor element. A control device may be used to supply energy to the electrodes, to produce tissue ablation that advances from individual-electrode ablation regions to fill a combined-electrode ablation volume. Information from the sensor element(s) is used for determining the extent of ablation in the regions of the sensor elements. The supply of energy to the electrodes can thus be regulated to control the level and extent of tissue ablation throughout the combined-electrode volume.

1 . A method of controlling the extent of tissue ablation, comprising: 
 deploying a plurality of electrodes from an elongate delivery device, the electrodes defining a tissue volume;    deploying at least one elongate sensor element in the tissue volume at a position remote from the plurality of electrodes;    delivering energy from an energy delivery device to ablate or necrose at least a portion of the tissue volume;    sensing a temperature of the tissue volume with the sensor element; and    regulating energy delivery based on the temperature sensed by the sensor element.    
     
     
         2 . The method of  claim 1 , wherein the elongate sensor element is deployed between the plurality of electrodes.  
     
     
         3 . The method of  claim 1 , further comprising: 
 determining a treatment endpoint responsive to the temperature of the tissue volume.    
     
     
         4 . The method of  claim 1 , wherein the sensor element measures temperature at two or more locations along the element.  
     
     
         5 . The method of  claim 1 , wherein the sensor element includes a thermal sensor for sensing temperature.  
     
     
         6 . The method of  claim 1 , wherein said electrodes and sensor element are deployed from their retracted to their deployed positions as a unit.  
     
     
         7 . The method of  claim 1 , wherein said electrodes are deployed independent of the deployment of the sensor element.  
     
     
         8 . The method of  claim 1 , wherein said electrodes are hollow-needle electrodes, further comprising: 
 injecting a liquid through said electrodes into the tissue volume.    
     
     
         9 . The method of  claim 8 , further comprising: 
 controlling liquid flow through each electrode individually.    
     
     
         10 . The method of  claim 8 , wherein at least one electrode has a plurality of infusion ports along its distal end region and a sheath, further comprising: 
 moving the sheath axially between deployment and infusion positions at which the infusion ports are covered and exposed, respectively.    
     
     
         11 . The method of  claim 1 , further comprising: 
 applying power between the plurality of electrodes and a body-surface electrode adapted to be applied to the surface of a patient.    
     
     
         12 . The method of  claim 1 , wherein said electrodes are RF electrodes and the energy delivered is RF energy.  
     
     
         13 . The method of  claim 1 , wherein said electrodes are microwave electrodes and the energy delivered is microwave energy.  
     
     
         14 . The method of  claim 1 , wherein said at least one elongate sensor element is deployed from the elongate delivery device.