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. 2020 Jul 30;26(11):1168–1177. doi: 10.1111/cns.13441

FIGURE 2.

FIGURE 2

Tumor Electric Field Treatment System and Operation. A, Tumor Electric Field Treatment System (TEFTS, ASCLU‐300). B, Instrument operation during experiments. C, Main components of TEFTS. a, Battery and charger; b, Junction box and connecting cables; c, the electric field generator; d, Electrodes. D, Electrodes and accessories. a, On the back of electrode; b, Thermistor and circuit; c, after installing thermistor and circuit; d, Two pairs of ceramic disk electrodes. Thermistors on the back of electrodes are connected to a temperature‐controlling device. The diameter of the disk electrode is 8 mm (dielectric constant ε ≈ 10 000, capacitance c ≈ 10 nF). Four electrodes are used as one treatment unit. The wire is coated with metal to prevent from gnawing; e, two positive‐negative pairs of electrodes connected by a flexible circuit board are arranged perpendicularly to each other. The surface of the electrode is covered with hydrogel, and the back is fixed on medical adhesive tapes (1. Thermistor; 2. Disk ceramic electrode; 3. Metal piping coated wires; 4. Flexible circuit board; 5. Medical adhesive tape). E, Installation of electrodes and measurement of electric fields. a, the red dots indicate the locations of four electrodes on the head of a rat; b, the electrodes are fixed on head by tapes; c, a head cover protects the electrode from being scratched by the rat with its forelegs; d, the electrodes and a head cover are fixed; e, f, the voltage measured from the scalp; g, h, the intracranial voltage measured. F, Schematic diagram showing the generation of alternating electric field. Waveform generator built in the field programmable gate array (FPGA) generates the digital signal of sine wave according to the preset parameters. The digital signal is converted into analog signal by a high‐speed discretionary access control (DAC) module, and then filtered. The analog signal is amplified by a power amplifier, outputs to the electrode plate affixed to the therapeutic target, and generates an alternating electric field inside the target