Nikita K S, Maratos N G, Uzunoglu N K
Department of Electrical and Computer Engineering, National Technical University of Athens, Greece.
IEEE Trans Biomed Eng. 1998 Jul;45(7):909-20. doi: 10.1109/10.686799.
A method is proposed for controlling the deposited power distribution in a layered cylindrical lossy model, irradiated by a phased-array hyperthermia system consisting of four waveguide applicators. A rigorous electromagnetic model of the heated tissue, which takes into account coupling phenomena between system elements, is used for predicting the electric field at any point inside tissue. The relative amplitudes and relative phases of the array elements are optimized in order to attain desired specific absorption rate (SAR) distributions inside and outside malignant tissues. A constrained nonlinear optimization problem is solved by using the penalty function method and the resulting unconstrained minimization of the penalty function is carried out by the downhill simplex method. Two practical phased-array hyperthermia systems have been studied and numerical results are presented.
提出了一种用于控制分层圆柱损耗模型中沉积功率分布的方法，该模型由由四个波导 applicator 组成的相控阵热疗系统进行辐照。考虑系统元件之间耦合现象的加热组织的严格电磁模型用于预测组织内任意点的电场。对阵列元件的相对幅度和相对相位进行优化，以在恶性组织内外获得所需的比吸收率（SAR）分布。使用惩罚函数法解决约束非线性优化问题，并通过下山单纯形法对惩罚函数进行无约束最小化。研究了两个实际的相控阵热疗系统并给出了数值结果。
