Exploring new instrumentation parameters for electrochemotherapy. Attacking tumors with bursts of biphasic pulses instead of single pulses

Electrochemotherapy using rectangular biphasic stimuli and bursts of stimuli, as compared to using monophasic pulses obtained by capacitor discharge, are at least of the same efficacy. The use of small surface electrodes in dermatological treatment yields electrode-skin impedances in the range of 200-400 ohms, with the impedances being almost entirely resistive. Therefore, generator output resistances can be in the range of 10 to 20 ohms. The use of a single burst of 50+50 μsec biphasic pulses, with an overall duration of about 7 msec, is well tolerated by the patients, causing just one short stimulus sensation instead of a succession of eight stimuli. The treatment results with the above-described instrumentation are comparable to those reported in the literature. Further studies are necessary in order to better understand the process of electropermeabilization in vivo, so as to determine optimal pulse duration, frequency, and waveform, and to eventually lower field intensity.