3-D Focused Microwave Hyperthermia for Breast Cancer Treatment With Experimental Validation

A 3-D focusing technique for noninvasive microwave hyperthermia treatment for breast cancer is presented and experimentally validated. The 3-D focusing is conducted to find the optimum excitations (phases and amplitudes) of a 3-D antenna array surrounding the breast using particle swarm optimization. The focusing approach aims at producing the required temperature (42 degrees C) at a tumor anywhere in the breast without causing hot spots in healthy tissue. Based on the modeling, a microwave system, which includes a 4.2-GHz source, power amplifier, two-stage power dividers, and phase shifters in addition to 24-element antenna array, was designed, built, and tested. The test was performed on the challenging scenario of a very dense breast phantom having 1-cm(3) tumor embedded in glands. The experiments were conducted on a 3-D printed phantom that has realistic dielectric and thermal properties. The breast phantom was irradiated for one hour while the temperature distribution was recorded by thermal imager at different time intervals. The results confirmed the capability of the proposed 3-D focusing technique and experimental system in using 65-W microwave power to elevate the temperature at tumor to more than 42 degrees C while keeping healthy tissue safe at 36 degrees C without any hot spots.