A Preclinical System Prototype and Experimental Validation of Focused Microwave Brain Hyperthermia

Focused microwave hyperthermia is a noninvasive, non-ionizing, and accurate treatment method that is promising for dealing with many kinds of cancers. Although focused microwave brain hyperthermia (FMBH) has been studied by some previous works, experimental evaluation of this technique in a practical experimental context has not been reported. This article aims to address this issue by developing a preclinical system prototype of FMBH and performing systematic experimental evaluation using several realistic head phantoms. We designed a 1.3-GHz hyperthermia applicator with 17 antennas and built nine different head phantoms based on a real human skull. We perform electromagnetic and thermal simulations and prove that the designed applicator can reliably achieve a good focused field and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$45~^{\circ }$ </tex-math></inline-formula>C temperature at the tumor. We then realize the FMBH system prototype and experimentally test the performance by applying fabricated 3-D head phantoms. The measured temperature results demonstrate that the FMBH system prototype is able to selectively treat the tumor. We also prove that the temperature at the tumor can be controlled at a constant level for a demanded time period for hyperthermia. This work provides a valuable experimental demonstration of the FMBH technique and is meaningful for its future development and clinical applications.