Efficient focusing of microwave hyperthermia for small deep-seated breast tumors treatment using particle swarm optimization

Focused microwave hyperthermia is a technique with advantage of high accuracy and low side effects for breast tumor treatments. In this study, an efficient focusing technique for noninvasive microwave hyperthermia treatment for breast tumors is presented. Particle Swarm Optimization (PSO) is used to find the optimum excitations (phases and amplitudes) of a three dimension (3D) Micro-Strip Patch (MSP) antenna array operating at 2.45 GHz. The antenna excitations are optimized to maximize the power loss density and the Specific Absorption Rate (SAR) at the tumor location, to reach the required hyperthermia temperature (above 42 °C) at the tumor location without causing hot spots in healthy tissues. The technique is tested on a challenging scenario of a 3D realistic breast model having a tumor less than 1 cm³ volume and embedded in different locations deep in the glandular tissue of a very dense breast. The results confirmed the capability of the focusing technique.