Optimal electric conditions in electrical impulse chemotherapy.

The relationship was examined between the tumoricidal effect and the electrical variables of in vivo electrical impulse chemotherapy. Donryu rats subcutaneously inoculated with AH-109AY hepatocellular carcinomas were given a single high-voltage electrical impulse of varying voltage and duration, 30 min after an intramuscular injection of 4 mg/kg bleomycin. As the voltage (V) was increased from 0 to 5 kV, the tumoricidal effect (E) increased in proportion to the square of the voltage. As the pulse duration (D) was increased from 2.5 to 5.8 ms, the tumoricidal effect increased in direct proportion to it. Combining these results yielded the formula, E = gamma V2D, which indicates that tumoricidal efficacy was proportional to the applied electrical energy. When the electrical energy was kept constant while varying the voltage and duration of pulse, the anticancer effect was the same, confirming this relationship for lower energy levels.