Ultrasonic heating with waveguide interstitial applicator array

Ultrasound interstitial applicators can be used for heating tumors near air and bone interfaces where use of non-invasive ultrasound methods becomes difficult. We describe in this paper an ultrasonic waveguide three-applicator array for interstitial waveguide three-applicator array for interstitial thermotherapy. We first discuss the temperature distribution and the pattern of heat deposition using the effective thermal conductivity equation. This equation is used then for finite element analysis of temperature modelling. We discuss heating in porcine brain tissue and present results with the array in a large volume tissue phantom. We compare the simulation results with the experiment. The average difference between measured and simulation temperatures was <0.4°C. Finally, we show that the arrays can be useful for thermotherapy if thermal conductivity of the medium is lowered or if modified, more powerful applicators are used