Interaction of High Frequency Electromagnetic Field with Biological Tissue: Application to Electromagnetic Property Measurement, Breast Cancer Detection and Neuro Stimulation of Brain

Understanding the interactions between high frequency electromagnetic waves with biological tissues, especially those in humans, are crucial in all aspects of today’s modern life where everyone is exposed to high frequency electromagnetic field, to some degree. More importantly, it can contribute to the design of electromagnetic medical imaging and therapeutic devices such as in the field of breast cancer detection and Transcranial Magnetic Stimulation (TMS). This dissertation is an attempt to provide a non-invasive and practical method for early detection of abnormalities occurred under human tissues particularly under breast tissue with the application to breast cancer detection and a novel coil design for Transcranial Magnetic Stimulation by exploring the relationship between high frequency electromagnetic field and the thermal reaction of biological tissue under the exposure of it. The presented work includes a detailed description of the relationship between the dielectric properties of biological tissue and the established electromagnetic (EM) field as well as the induced heat due to external EM field. Based on these relationships, a new design of coil has been proposed to solve one of the dilemmas encountered in TMS. Furthermore, a novel breast cancer detection technique was proposed based on traditional Thermal Imaging technique. Multi-physics simulations are used to demonstrate the validity of the operating characteristics of those techniques. A physical design of the coil and a prototype test bed for the detection technique was utilized to experimentally verify the feasibility of the method and the accuracy of the simulation results. The robustness of the detection technique was tested by using different simulation frequencies, different sizes of tumor tissue as well as different locations of the tumor. The results of this investigation indicates that the proposed methods and apparatus are feasible tools for use in the field.