Methods for enhancing and modulating reversible and irreversible electroporation lesions by manipulating pulse waveforms

A method for electroporation, the method comprising:

• selecting a desired treatment size for an ablation therapy treatment zone;
• inserting one or more therapeutic source electrodes into a target tissue;
• placing one or more sink electrodes in contact with the target tissue;
• selecting automatically by a computer an asymmetric bipolar pulse waveform that has positive pulses and negative pulses with different durations, wherein the computer computes a ratio of durations of the positive pulses and the negative pulses from the desired treatment size such that the ratio varies with the desired treatment size;
• delivering to the target tissue a series of electrical pulses having the selected asymmetric bipolar pulse waveform;
• whereby the desired treatment size for the ablation treatment zone may be controlled to either minimize or enhance ablation of cells in the target tissue.