Optimizing ultrasound focus distributions for hyperthermia.

Abstract

A method is described for generating ultrasound focus patterns for ultrasound hyperthermia treatment planning for steady state and transient hyperthermia. The solution for placement and intensity of ultrasound focus points is based on two types of temperature constraints: 1) equality constraints on the tumor boundary (temperature is held at maximum safe level) and 2) inequality constraints in the tumor interior (in a therapeutic range of temperatures). The method employs a simplex algorithm to solve a series of linear equations which approximate the heating distribution in tissue. Examples are given for field conjugate acoustic lens applicators capable of generating multiple foci simultaneously.