A system for delivering a therapeutic agent to a target tissue, the system comprising: a needle having a distal end and a proximal end and a lumen that communicates between the proximal and distal ends; a guidewire with proximal and distal ends and having a diameter less than the diameter of the needle lumen, the guidewire further having anchoring means on its distal end; a source of therapeutic agent; an energy source; and a cannula comprising: a proximal and distal end; two or more electrodes disposed at distance D e from one another on the distal end of the cannula, the electrodes being comprised of a conductive metal and comprising an electrically conductive portion and configured to electrically couple to an energy source; a plurality of pores located between the electrodes; a lumen for the guidewire, wherein the lumen has a diameter greater than the diameter of the guidewire; and a main lumen for the therapeutic agent, the main lumen in communication with the proximal end of the cannula and the plurality of pores; wherein the center of the lumen for the guidewire is separated from the center of the main lumen by a distance D L; wherein the plurality of pores are in communication with the exterior of the cannula and the main lumen of the cannula; wherein an energizing potential can be applied to the electrodes to create an electric field to which target tissue may be exposed. a needle having a distal end and a proximal end and a lumen that communicates between the proximal and distal ends; a guidewire with proximal and distal ends and having a diameter less than the diameter of the needle lumen, the guidewire further having anchoring means on its distal end; a source of therapeutic agent; an energy source; and a cannula comprising: a proximal and distal end; two or more electrodes disposed at distance D e from one another on the distal end of the cannula, the electrodes being comprised of a conductive metal and comprising an electrically conductive portion and configured to electrically couple to an energy source; a plurality of pores located between the electrodes; a lumen for the guidewire, wherein the lumen has a diameter greater than the diameter of the guidewire; and a main lumen for the therapeutic agent, the main lumen in communication with the proximal end of the cannula and the plurality of pores; wherein the center of the lumen for the guidewire is separated from the center of the main lumen by a distance D L; wherein the plurality of pores are in communication with the exterior of the cannula and the main lumen of the cannula; a proximal and distal end; two or more electrodes disposed at distance D e from one another on the distal end of the cannula, the electrodes being comprised of a conductive metal and comprising an electrically conductive portion and configured to electrically couple to an energy source; a plurality of pores located between the electrodes; a lumen for the guidewire, wherein the lumen has a diameter greater than the diameter of the guidewire; and a main lumen for the therapeutic agent, the main lumen in communication with the proximal end of the cannula and the plurality of pores; wherein the center of the lumen for the guidewire is separated from the center of the main lumen by a distance D L; wherein the plurality of pores are in communication with the exterior of the cannula and the main lumen of the cannula; wherein the center of the lumen for the guidewire is separated from the center of the main lumen by a distance D L; wherein the plurality of pores are in communication with the exterior of the cannula and the main lumen of the cannula; wherein an energizing potential can be applied to the electrodes to create an electric field to which target tissue may be exposed.