For irreversible-electroporation (IRE)-based therapies, the underlying electric field distribution in the target tissue is influenced by the electroporation-induced conductivity changes and is important for predicting the treatment zone. Objective: In this study, we characterized the liver tissue conductivity changes during high-frequency irreversible electroporation (H-FIRE) treatments of widths 5 and 10 μs and proposed a method for predicting the ablation zones. Methods: To achieve this, we created a finite-element model of the tissue treated with H-FIRE and IRE pulses based on experiments conducted in an in-vivo rabbit liver study. We performed a parametric sweep on a Heaviside function that captured the tissue conductivity versus electric field behavior to yield a model current close to the experimental current during the first burst/pulse. A temperature module was added to account for the current increase in subsequent bursts/pulses. The evolution of the electric field at the end of the treatment was overlaid on the experimental ablation zones determined from hematoxylin and eosin staining to find the field thresholds of ablation. Results: Dynamic conductivity curves that provided a statistically significant relation between the model and experimental results were determined for H-FIRE. In addition, the field thresholds of ablation were obtained for the tested H-FIRE parameters. Conclusion: The proposed numerical model can simulate the electroporation process during H-FIRE. Significance: The treatment planning method developed in this study can be translated to H-FIRE treatments of different widths and for different tissue types.

High-frequency bipolar high-voltage pulsed electric field can be used in tumor ablation to uniform the electric field distribution in the ablated region and inhibit muscle contraction effectively. Developing a high-frequency bipolar pulsed power generator (HBPPG) with wide range of specifications such as voltage magnitude, waveform, repetition rate and pulse width, is of great significance for promoting the clinical application of irreversible electroporation. Hence, in this study, a novel modular high-voltage HBPPG circuit topology is proposed for such application. Each module consists of an H-bridge and an isolated inductor. Theoretical analysis, simulation and experimental results show that this generator perfectly combines the advantages of solid-state Marx and bridge circuit, with high stability and redundancy. The pulse frequency, pulse duration and waveform can be flexibly adjusted by controller software algorithm according to load parameters. The viability of the proposed HBPPG is demonstrated by PSpice simulation and equal-scale prototype. The key parameters of the developed HBPPG show as following: voltage amplitude up to ±10 kV with 500 ns-5 μs pulse widths, 500 kHz within the burst and 10 kHz within the continuation limited by the input high-voltage DC power supply. All the pulse parameters can be programmed arbitrarily.

In order to solve problems, such as the nonadjustable drive pulsewidth of semiconductor lasers, in this article, an all-solid-state modular pulse current generator (PCG) topology based on a coupling inductor is proposed. Each stage of the PCG consists of one inductor, two switches, and a diode. The inductors are charged in series and discharged parallel to the load by controlling the timing. The design of the coupling inductor makes it possible to increase the energy storage density of the system. To reduce the requirement for a high-voltage power supply, the capacitor is first charged by the dc power supply, and then charge the energy storage inductor. Theoretical analysis, simulation, and prototype development verify the correctness and feasibility of the PCG. A seven-stage PCG prototype is developed: at a charging voltage of 0–500 V, an adjustable output of 0–200 A is achieved. The maximum pulsewidth can reach 5 μ s with a rise time and fall time of 100 ns at resistive–capacitive load. The repetition frequency can reach 100 Hz. Finally, the PCG is successfully applied to laser arrays.

Pulsed electric fields have recently been the focus of considerable attention because of their potential application in biomedicine. However, their practical clinical applications are limited by poor understanding of the interaction mechanism between pulsed electric fields and cells, particularly in the process of electroporation and its effect on parameter selection. This paper established a multishelled dielectric model based on finite elements to simulate and analyze the processes involved in electroporation. In particular, the processes include the dynamic development of the pore radius and electroporation region: the distribution of recoverable, nonrecoverable, and nonelectroporation areas on the cell; and the influence of pulse parameters on varying degrees of electroporation. Results showed that membrane conductivity, pore density, transmembrane potential, and distribution of pore radii are functions of time and position on the cell. The electroporation areas were divided into recoverable, nonrecoverable, and no-electroporation pores. For 10 μs, 1.5-kV/cm pulse was observed in the regions exposed to sufficiently high transmembrane voltage (1 V), electroporation occurred, membrane conductivity and pore density (up to 10 ¹⁶ /m ² rapidly increased with time, and electroporation areas increased gradually and were mainly distributed in the range 0°-70° (recoverable pore [0°, 35°], nonrecoverable pore [35°, 70°], and no-electroporation pore [70°, 90°]). Electric field strength was the major factor that induced electroporation, particularly in the recoverable pore, but it had minimal effect on pore expansion. However, pulse duration affects the nonrecoverable pore, such that the high-intensity wide pulse is more useful in the field of irreversible electroporation. The high-intensity short pulse can increase permeability and maintain cell viability.

In recent years, pulsed magnetic field (PMF) have attracted significant attention as a non-invasive electroporation method in the biomedical field. To further explore the biomedical effects generated by oscillating PMF, we designed a novel PMF generator for biomedical research. Based on resonance principles, the designed generator outputs sinusoidal oscillating PMF. To validate the feasibility and application value of the designed topology, a miniaturized platform was constructed using a selected multi-turn solenoid coil. The output performance of the generator was tested under different discharge voltage levels. The results revealed that the current multiplication factor remained consistently around 2 times, with the energy efficiency and circuit quality factor maintained at 82% and above 4.5, respectively. In addition, the generator’s ability to flexibly modulate the number of pulse oscillations was demonstrated. The compatibility of the designed coil parameters and generator circuit parameters was analyzed, with tests on the effects of coil resistance and switch action time on the generator’s output performance. Based on the magnetic field action platform, a simulation model of the actual scale coil was established. The spatial and temporal distribution of the magnetic field, induced electric field, and power transmission in the target area were described from multiple angles. Finally, biological experiments conducted using the constructed generator revealed the synergistic effect of sinusoidal oscillating PMF combined with drugs in tumor cell killing.

This article presents a new type of all solid state boost Marx pulse generator. On the basis of the classic pulse forming Marx circuit, without changing the voltage level of each voltage module, a new switch is added for the isolated inductor energy storage and recovery, so as to realize the output of high-voltage nanosecond pulses. At the same time, in order to improve the voltage level of the semiconductor switch and break the limitation of the voltage of the single-stage pulse forming circuit, a series-connected silicon carbide (SiC) metal-oxide-semiconductor field effect transistor ( mosfet s) with a single external driver is designed. The series switch has a simple structure with few components and is extremely easy to use in a modular high voltage pulse generator. Its theoretical feasibility is verified by mathematical model and circuit simulation, and the ten-stage prototype is built in this article. Under the condition of input dc voltage of 500 V, it can output 18 kV high voltage pulses of 200–1200 ns, and the gain multiple has reached 36 times.