Development of a Simulation Framework and Experimental Setup for Improved Temperature Monitoring during Microwave Hyperthermia Treatments

Hyperthermia is a form of medical therapy, often used in cancer treatments, that involves the heating of tumor cells in the body via non-ionizing radiation. It is an adjuvant therapy that is used in conjunction with chemotherapy and/or radiotherapy to enhance their effectiveness and overall success rate. Hyperthermia can supplement the aforementioned therapies by shrinking the tumor cells or further sensitizing them to microwave radiation, as well as by augmenting their drug absorption levels. A successful therapy treatment is contingent on sufficiently and accurately heating the target region, generally in the range of 40-44°C, without harming the surrounding healthy tissues. In clinical practice, the heating can be administered using several different methods including local, regional, and whole-body hyperthermia. In the case of this study, the heating was administered locally to a neck phantom designed to replicate the electrical properties of the human muscle, as described in existing literature, with a target sphere inserted to reproduce the presence of a tumor mass. The phantom was surrounded by a circular array of patch antennas, appropriately configured to concentrate the specific absorption rate (SAR) on the tumor target, thereby minimizing the formation of hotspots in the surrounding region. In order to effectively heat the target region, antenna feedings were maintained constant during the entirety of the heating session using a closed-loop electronic control system. The subsequent temperature data was then collected in real-time at several different points distributed in the neck phantom using fiber optic sensors. The following thesis presents an elaboration of the design, setup, and characterization of the prototyped neck hyperthermia applicator through experimental testing, model simulation, and numerical regularization methods. Specifically, this work will outline an evaluation of the updated experimental and electronic setup, the optimization of specific parameters used in COMSOL Multiphysics to accurately reproduce the prototyped system, a comparison between experimental and simulated temperature maps, and the numerical regression and regularization techniques applied to improve the temperature reconstruction in the whole neck region using a reduced sample of experimental data.