SYSTEM AND METHOD FOR CONTROLLED TISSUE HEATING FOR DESTRUCTION OF CANCEROUS CELLS

1 . A method of delivering controlled heating to a tissue of a patient, comprising:

positioning a plurality of electrodes in a target tissue region; and

establishing an electrical current flow radially or in a plurality of different directions through a volume of the tissue so as to preferentially ablate cancerous cells in the volume, wherein electrical current flow is established so as to heat the target tissue to an average temperature of about 40-48 degrees C.

2 . The method of claim 1 , the electrical current flow comprising a alternating current having a frequency of less than about 300 kHz.

3 . A method of delivering controlled heating to a target tissue of a patient for preferential destruction of cancerous cells in the target tissue, comprising:

positioning a plurality of electrodes in the target tissue region, the plurality comprising an array of needle electrodes advanced through the patient's tissue and positioned in the target tissue region; and

differentially activating groups of electrodes of the plurality so as to establish an electrical current flow in a plurality of different directions through a volume of the target tissue and preferentially destroy cancerous cells in the volume, wherein electrical current flow is established so as to heat the target tissue to an average temperature of about 40-48 degrees C.

4 . The method of claim 3 , wherein the positioning comprises advancing electrodes through guides of a template device.

5 . The method of claim 3 , wherein the differentially activating comprises activating different groups of two or more electrodes of the array in seriatim.

6 . The method of claim 3 , wherein the electrical current comprises an alternating current flow comprising a frequency of about 50 to about 250 kHz.

7 . The method of claim 3 , wherein the electrical current comprises an alternating current flow comprising a frequency of about 100 kHz.

8 . A system for preferential destruction of cancerous cells of a target tissue of a patient, comprising:

a plurality of electrodes for advancement and positioning in a target tissue region of the patient;

a control system comprising a power source coupled to the electrodes, and a computer readable storage media comprising instructions that, when executed, cause the control system to:

provide electrical current to the electrodes so as to establish a current flow radially or in a plurality of different directions through a volume of the tissue and to preferentially destroy cancerous or hyperplastic cells in the target tissue region;

maintain an average target tissue temperature of less than about 50 degrees C. during energy delivery.

9 . A system for preferential destruction of cancerous cells of a target tissue of a patient, comprising:

an array of electrodes for advancement and positioning in a target tissue region of the patient;

a control system comprising a power source coupled to the electrodes, and a computer readable storage media comprising instructions that, when executed, cause the control system to differentially activate groups of electrodes of the plurality so as to establish an electrical current flow in a plurality of different directions through a volume of the target tissue and preferentially destroy cancerous cells in the volume, wherein electrical current flow is established so as to heat the target tissue to an average temperature of about 40-48 degrees C.

10 . The system of claim 8 , wherein the differentially activating comprises activating different groups of two or more electrodes of the array in seriatim.

11 . The system of claim 8 , wherein the electrical current comprises an alternating current flow comprising a frequency of less than about 300 kHz and a voltage field of less than about 50 V/cm.

12 . A method of delivering an electric field to a target tissue, comprising:

positioning an ablation probe in a tissue of a patient;

deploying a plurality of outer electrodes from the probe to define an ablation volume having a current flow center, wherein deploying an electrode of the plurality comprises deploying a first microtube from a delivery member of the probe along a guide path curving in at least a first direction, wherein curving of the microtube in the first direction directs advancement of the guide distally and away from the current flow center, deploying a second microtube from the first microtube in a second direction distally and substantially parallel to a long axis of the delivery member; and deploying an electrode from a lumen of the second microtube such that the electrode is advanced along an electrode tissue penetration path advancing distally and substantially parallel to the long axis of the delivery member;

positioning an inner electrode substantially within the ablation volume and at the current flow center;

establishing current flow between the inner electrode and outer electrodes and through the ablation volume to provide one or more electric fields extending through the volume in a plurality of different directions, wherein establishing current flow comprises applying an alternating current so as to preferentially destroy cancerous cells within the ablation volume compared to non-cancerous cells within the ablation volume.