Devices and methods for remote temperature monitoring in fluid enhanced ablation therapy

Abstract

Devices and methods for monitoring the temperature of tissue at various locations in a treatment volume during fluid enhanced ablation therapy are provided. In one embodiment, an ablation device is provided having an elongate body, at least one ablation element, and at least one temperature sensor. The elongate body includes a proximal and distal end, an inner lumen, and at least one outlet port to allow fluid to be delivered to tissue surrounding the elongate body. The at least one ablation element is configured to heat tissue surrounding the at least one ablation element. The at least one temperature sensor can be positioned a distance away from the at least one ablation element and can be effective to output a measured temperature of tissue spaced a distance apart from the at least one ablation element such that the measured temperature indicates whether tissue is being heating to a therapeutic level.

What is claimed is: 
     
         1 . An ablation device, comprising:
 a elongate body having a proximal end, a distal end, an inner lumen extending therethrough, and at least one outlet port configured to allow fluid flowing through the inner lumen to be delivered to tissue surrounding the elongate body when the elongate body is introduced into a tissue mass;   at least one ablation element disposed along the elongate body adjacent to the at least one outlet port, the at least one ablation element being configured to heat tissue within a treatment zone surrounding the at least one ablation element when the distal end of the elongate body is introduced into a tissue mass; and   at least one temperature sensor coupled to the elongate member and positioned a distance apart from the at least one ablation element, the at least one temperature sensor being effective to output a measured temperature of tissue spaced a distance apart from tissue adjacent to the at least one ablation element such that the measured temperature indicates whether tissue is being heating to a therapeutic level.   
     
     
         2 . The ablation device of  claim 1 , wherein the at least one temperature sensor is positioned on the elongate body at a location proximal to the at least one ablation element. 
     
     
         3 . The ablation device of  claim 1 , wherein the at least one temperature sensor is positioned on the elongate body at a location distal to the at least one ablation element. 
     
     
         4 . The ablation device of  claim 1 , wherein the at least one temperature sensor comprises a plurality of temperature sensors spaced apart from one another and positioned axially along the elongate body. 
     
     
         5 . The ablation device of  claim 1 , wherein the elongate body includes a plurality of tines configured to extend outward from the elongate body, and wherein the at least one temperature sensor comprises a plurality of temperature sensors, each of the plurality of tines having one of the plurality of temperature sensors located at a distal tip thereof. 
     
     
         6 . The ablation device of  claim 5 , wherein each of the plurality of tines has two or more of the plurality of temperature sensors disposed along a length thereof. 
     
     
         7 . The ablation device of  claim 1 , wherein the at least one temperature sensor comprises a first temperature sensor positioned distal of the at least one ablation element, and a second temperature sensor positioned proximal of the at least one ablation element. 
     
     
         8 . The ablation device of  claim 1 , wherein the at least one temperature sensor is located on an outer surface of the elongate body. 
     
     
         9 . The ablation device of  claim 1 , wherein the at least one temperature sensor is located in the inner lumen and contacts an outer wall of the elongate body. 
     
     
         10 . The ablation device of  claim 1 , wherein the at least one temperature sensor is located in a recess formed in the elongate body. 
     
     
         11 . The ablation device of  claim 1 , wherein the at least one temperature sensor is thermally isolated from the elongate body. 
     
     
         12 . The ablation device of  claim 1 , wherein a position of the at least one temperature sensor is adjustable along a length of the elongate member. 
     
     
         13 . The ablation device of  claim 1 , wherein the at least one temperature sensor comprises a thermocouple. 
     
     
         14 . A system for delivering saline enhanced ablation, comprising:
 an elongate body having
 proximal and distal ends, 
 an inner lumen extending through the elongate body, 
 at least one outlet port formed in the elongate body, and 
 at least one ablation element positioned along the length of a distal portion of the elongate body; 
   a fluid source in communication with the inner lumen of the elongate body and configured to deliver fluid through the inner lumen such that fluid can flow through the at least one outlet port and be delivered to tissue surrounding the at least one ablation element;   at least one temperature sensor coupled to the elongate body and positioned a distance apart from the at least one ablation element such that the at least one temperature sensor is effective to measure a temperature of tissue spaced a distance apart from tissue adjacent to the at least one ablation element; and   a control unit configured to obtain a temperature of the ablation element and a temperature measured by the at least one temperature sensor;   wherein a temperature measured by the at least one temperature sensor indicates whether tissue within a treatment zone is being heated to a therapeutic level.   
     
     
         15 . The system of  claim 14 , wherein the control unit is configured to adjust at least one of a flow rate of the fluid flowing through the elongate body, an ablative energy level of the ablation element, and a temperature of the fluid being delivered in response to a temperature measured by the at least one temperature sensor. 
     
     
         16 . A method for ablating tissue, comprising:
 inserting a needle body into a tissue mass, the needle body having an ablation element disposed thereon and at least one temperature sensor coupled thereto and effective to measure a temperature of the tissue mass at a distance away from tissue immediately adjacent to the ablation element; and   simultaneously delivering fluid through the needle body and into the tissue mass surrounding the needle body and delivering therapeutic energy to the ablation element on the needle body to heat the tissue mass surrounding the needle body;   wherein the at least one temperature sensor measures a temperature of the tissue mass at a distance away from the tissue immediately adjacent to the ablation element.   
     
     
         17 . The method of  claim 16 , further comprising adjusting at least one of a flow rate of the fluid flowing through the needle body, an ablative energy level of the ablation element, and a temperature of the fluid being delivered. 
     
     
         18 . The method of  claim 16 , wherein the tissue located the distance away from the tissue immediately adjacent to the ablation source is at the periphery of a desired treatment zone. 
     
     
         19 . The method of  claim 16 , further comprising ceasing delivery of therapeutic energy once the temperature measured by the at least one temperature sensor reaches a predetermined level. 
     
     
         20 . The method of  claim 16 , determining a therapeutic dose delivered to the tissue mass based on measurements from the at least one temperature sensor; and
 ceasing delivery of therapeutic energy once the thermal dose delivered to the tissue mass reaches a predetermined level.   
     
     
         21 .- 22 . (canceled)