Controlled irreversible electroporation

Abstract

Electrical pulses are applied to tissue in a manner which destroys targeted cells such as cancerous cells while sparing non-targeted cells such as nerve cells. The electrical pulses are controlled within ranges for voltage, wattage and duration of application. Multiple pulses or groups of pulses may be applied to obtain a desired result while maintaining any temperature increase below a level which destroys cells.

1 .- 20 . (canceled) 
     
     
         21 . A method comprising the steps of:
 identifying cells to be ablated in a target area, wherein the target area comprises heterogenous tissue comprising nerve tissue surrounded by myelin layers;   selecting a size, shape, or relative position of a first electrode and a second electrode;   placing the first electrode and the second electrode in the target area; and   applying electrical pulses between the first electrode and the second electrode in an amount which compensates for tissue heterogeneity, and is sufficient to irreversibly electroporate the cells in the target area; wherein voltage, wattage and duration of the electrical pulses are maintained within ranges which avoid thermal damage to nerve tissue and the cells in the target area.   
     
     
         22 . The method of  claim 21 , wherein the myelin layers insulate the nerve tissue from thermal damage. 
     
     
         23 . The method of  claim 21 , further comprising:
 monitoring temperature of the heterogeneous tissue and adjusting the electrical pulses to maintain the temperature at 50° C. or less for a period of time that avoids thermal damage to cells of the heterogeneous tissue.   
     
     
         24 . The method of  claim 21 , further comprising:
 infusing a material into the heterogenous tissue prior to applying the electrical pulses.   
     
     
         25 . The method of  claim 24 , wherein the material is a chemotherapeutic agent. 
     
     
         26 . The method of  claim 24 , wherein the material is an imaging agent. 
     
     
         27 . The method of  claim 21 , wherein the first electrode and the second electrode are substantially circular in shape; and
 wherein the first and second electrodes are positioned within less than 2 cm of each other.   
     
     
         28 . A method comprising the steps of:
 identifying a target ablation area, wherein the target ablation area is heterogenous tissue comprising cells and mammary ducts, wherein the mammary ducts are surrounded by myoepithelial cells;   placing a first electrode and a second electrode in the target ablation area; and   applying electrical pulses between the first electrode and the second electrode in an amount which compensates for tissue heterogeneity, and is sufficient to irreversibly electroporate the cells in the target ablation area; wherein voltage, wattage and duration of the electrical pulses are maintained within ranges which avoid damage to the mammary ducts and the cells in the target ablation area.   
     
     
         29 . The method of  claim 28 , wherein the myoepithelial cells insulate the mammary ducts from thermal damage. 
     
     
         30 . The method of  claim 28 , further comprising:
 monitoring temperature of the heterogeneous tissue and adjusting the electrical pulses to maintain the temperature at 50° C. or less for a period of time that avoids thermal damage to the cells of the heterogeneous tissue.   
     
     
         31 . The method of  claim 28 , further comprising:
 infusing a material into the heterogenous tissue prior to applying the electrical pulses.   
     
     
         32 . The method of  claim 28 , wherein the material is a chemotherapeutic agent. 
     
     
         33 . The method of  claim 31 , wherein the material is an imaging agent. 
     
     
         34 . The method of  claim 31 , wherein the first electrode and the second electrode are substantially circular in shape; and
 wherein the first and second electrodes are positioned within less than 2 cm of each other.   
     
     
         35 . A method comprising the steps of:
 identifying a target ablation area, wherein the target ablation area is comprised of heterogenous tissue comprising cancer cells and nerve tissue, wherein the nerve tissue is surrounded by myelin layers;   placing a first electrode and a second electrode in the target ablation area; and   applying electrical pulses between the first electrode and the second electrode in an amount which compensates for tissue heterogeneity, and is sufficient to irreversibly electroporate the cancer cells in the target ablation area; wherein voltage, wattage and duration of the electrical pulses are maintained within ranges which avoid damage to the nerve tissue.   
     
     
         36 . The method of  claim 35 , wherein the myelin layers insulate the nerve tissue from thermal damage. 
     
     
         37 . The method of  claim 35 , further comprising:
 monitoring temperature of the heterogeneous tissue and adjusting the electrical pulses to maintain the temperature at 50° C. or less for a period of time that avoids thermal damage to cells of the heterogeneous tissue.   
     
     
         38 . The method of  claim 35 , further comprising:
 infusing a material into the heterogenous tissue prior to applying the electrical pulses.   
     
     
         39 . The method of  claim 38 , wherein the material is a chemotherapeutic agent. 
     
     
         40 . The method of  claim 38 , wherein the material is an imaging agent. 
     
     
         41 . The method of  claim 35 , wherein the first electrode and second electrode are substantially circular in shape; and
 wherein the first and second electrodes are positioned within less than 2 cm of each other.