positioning a plurality of elongated electrodes disposed lengthwise and circumferentially spaced a selected distance from one another at the target lesion;

selecting any combination of electrodes among the plurality of electrodes for administering a plurality of electrical pulses; and

activating a generator to administer the plurality of electrical pulses through only the selected electrodes to the target lesion in an amount which is sufficient to induce irreversible electroporation of cells of the target lesion, wherein at least one of the electrical pulses is applied with a pulse duration of from 1 μs to 1 ms, wherein at least one of the electrical pulses is applied to a first pair of electrodes comprising a first electrode and a second electrode separated by at least one unenergized electrode, wherein the administration of the plurality of electrical pulses through only the selected electrodes treats tissue proximate the energized electrodes while tissue proximate the un-energized electrodes is substantially untreated.