OPTIMAL STEADY-STATE TEMPERATURE DISTRIBUTION FOR A PHASED-ARRAY HYPERTHERMIA SYSTEM

A method is presented for the evaluation of optimal amplitude and phas e excitations for the radiating elements of a phased array hyperthermi a system, in order to achieve desired steady-state temperature distrib utions inside and outside of malignant tissues. Use is made of a detai led electromagnetic and thermal model of the heated tissue in order to predict the steady-state temperature at any point in tissue. Optimal excitations are obtained by minimizing the squared error between desir ed and model predicted temperatures inside the tumor volume, subject t o the constraint that temperatures do not exceed an upper bound outsid e the tumor. The penalty function technique is used to solve the const rained optimization problem. Sequential unconstrained minima are obtai ned by a modified Newton method. Numerical results for a four element phased array hyperthermia system are presented.