高频纳秒脉冲串作用下皮肤肿瘤热效应的多参数有限元仿真与实验

为综合传统微秒脉冲电场和纳秒脉冲电场治疗肿瘤的优点,提出一种高频纳秒脉冲串的脉冲形式来治疗肿瘤。研究此高频纳秒脉冲串在生物组织中产生的热效应,并通过多参数有限元方法对施加镊子电极的皮肤黑色素肿瘤的温度以及热损伤进行仿真。施加的电场强度范围为1~10k V/cm,脉宽范围为50~500ns,脉冲串内重复频率介于100k Hz和1MHz之间,一串脉冲的长度为100μs,脉冲串重复频率为1Hz。对于皮肤肿瘤,施加电场强度5k V/cm、脉宽500ns、脉冲串内重复频率1MHz的脉冲,1s后肿瘤的最高温度仅为37.4℃,热损伤可以忽略不计。对不同电场强度、脉宽、重复频率下皮肤黑色素肿瘤的温度和热损伤进行仿真计算,研究肿瘤温度以及热损伤与脉冲参数的关系,并确定使肿瘤不发生热损伤的脉冲参数范围。对裸鼠在体黑色素肿瘤的温度进行实测,肿瘤的温升结果与仿真中的平均温度变化较为一致。

Thermal Effects in Skin Tumor Exposed to High-Frequency Nanosecond Pulse Bursts: Multi-Parametric Finite Element Simulation and Experiment

Combined with the advantages of microsecond pulsed electric field and nanosecond pulsed electric field for the treatment of tumors, this work introduces high-frequency nanosecond pulse bursts. To study the thermal effects of the high-electric-field nanosecond pulses in tissue, a multi-parametric analysis is carried out based on a finite element model of skin with a melanoma tumor nipped by splint electrodes. The electric field ranges from 1 to 10kV/cm, the pulse width ranges from 50 to 500ns, and the frequency in the pulse bursts ranges between 100kHz and 1MHz. The total pulse length is 100μs, and the frequency of the pulse bursts is 1Hz. The simulated maximum temperature of the skin tumor is only 37.4℃ after 1s, and the thermal damage is negligible, where the pulse parameters are 5kV/cm, 500ns and 1MHz. The temperature and thermal damage of the melanoma tumor in the skin are simulated and calculated with different electric fields, different pulse widths and different frequencies. The relationship between the thermal effects on the tumor and the pulse parameters is researched, and pulse parameters for a tumor without thermal damage are ascertained. By measuring the temperature of melanoma tumors in nude mice in vivo, it shows that the change in experimental temperature of the tumors is consistent with the simulated average temperature.