The research of the antenna system to superimpose electric fields for cancer treatment by an ultra-short pulse high electric field

纳秒和亚纳秒的高压脉冲可以提供新的应用。超短脉冲强电场治疗癌症就是其中之一。高功率脉冲电磁波已被提出应用于高压电场治疗。本工作的重点是设计一种紧凑型高功率脉冲电磁波发生器，采用纳秒脉冲功率发生器用于癌症治疗。在本研究中，L-C逆变电路被用于脉冲功率发生器，以获得用于施加天线的单频电压波形。针对L-C逆变电路中水隙开关电感小、回路电感小的特点，采用水隙开关和水电容作为逆变电路的介质，使电路的环路电感变小。L-C逆变电路采用水隙开关和水电容，脉冲电压的频率元素为250 MHz。在本实验中，电磁波通过环形天线辐射到水下。水被用来制作最简单的组织模型，因为组织里面有很多水。测量了辐射天线在10KV电压作用下的电场强度。将测量天线放置在距辐射天线0.15的位置，捕捉到112kV/m的电场强度，在辐射天线上安装聚焦杯，以获得较高的电场。焦点处的峰值电场强度为11.3kV/cm。电场强度大于10.8kV/cm的区域在焦点周围辐射轴方向、另一水平轴方向和深度方向上分别为5 mm、5 mm和3 mm。

Nanosecond and sub-nanosecond high voltage pulses can provide new applications. A cancer treatment by an ultra-short pulse high electric field is one of them. High power pulsed electromagnetic wave has been proposed to apply the high electric field for that treatment. This work focuses on the design of a compact high power pulsed electromagnetic wave generator using a nanosecond pulse power generator for the cancer treatment. In this study, a L-C inversion circuit was employed for the pulsed power generator to obtain a voltage waveform with a single frequency for applying an antenna. A water gap switch and a water capacitor were used for L-C inversion circuit to obtain the frequency of hundreds MHz, because the water gap switch has a low inductance property and the loop inductance of the circuit can be made small using the same medium for the capacitor and the switch. By using the water gap switch and the water capacitor for the L-C inversion circuit, the pulsed voltage had the frequency element of 250 MHz. The electromagnetic wave was radiated underwater by the loop antenna in this experiment. Water was used for a simplest phantom of tissues because tissues have much water inside. The intensity of electric field was measured at 10 kV of applying voltage to the radiating antenna. Ameasuring antenna put at 0.15 from the radiating antenna caught the electric field intensity of 112 kV/m A focusing bowl was equipped on the radiating antenna to obtain higher electric field. The peak electric field intensity is 11.3 kV/cm at a focal point. The area of the electric field intensity over 10.8 kV/cm is 5 mm, 5 mm and 3 mm on the direction of the radiating axis, the other horizontal axis and the axis in depth direction around the focal point, respectively.