A study of re-entrant type cavity applicator hyperthermia system for deep seated tumor

报道了一种对深层肿瘤具有有效加热特性的热疗系统的研究。该系统有一个独特的施加器，由一个可再入腔谐振器组成。采用FD-TD方法对再入腔施加器的能量分布进行了计算机模拟。根据模拟的结果，我们估计加热特性随被加热材料的电常数而变化。对于优化设计计算，直径大小、谐振器高度和折返器高度的改变不会影响能量分布。在模拟数据的基础上，设计并组装了可再入腔式喷射器，并对其加热特性进行了实验研究。设计了一种适用于不同形状、大小被加热材料的频率变化的宽带大功率电源。采用脉冲电机驱动电容和体模温度计算机控制系统对匹配部分进行了改进。为了获得集中加热模式，进行了改变折返器直径的实验。电浓缩装置对于集中供热是非常有效的。对体模电常数变化的测量表明，肌肉的电常数是该系统集中加热的临界点。关于临床使用的电常数，进一步开发是必要的。

A study is reported of a hyperthermia system having effective heating characteristics for deep seated tumor. This system has a unique applicator consisting of a re-entrant cavity resonator.1. Computer simulation with FD-TD method was carried out to estimate energy distribution of the re-entrant cavity applicator. We estimate from the results of this simulation the heating characteristics vary with electric constants of heated materials.2. For optimum design computation change of the size of diameter, hight of resonator and re-entrant does not affect the energy distribution.3. On the basis of the simulation data we designed and composed a re-entrant cavity applicator and examined experimentaly the heating characteristics.4. We also designed a wide band high power generator which available for frequency change of various shapes and sizes of the heated materials.5. Improvement of matching section with pulse motor driven capacitors and computer control system of a phantom temperature was performed.6. To obtain concentrated heated pattern, experiment of changing the diameter of re-entrant was done. An electric concentration apparatus was very effective for concent rated heating.7. Measurements of heated pattern varing electric constants of phantoms revealed that the electric constants of the muscle is critical point for concentrated heating in this system. Further development is necessary concering electric constants for clinical use.