La Radiometria a microonde per la diagnosi del tumore al seno

Interest in breast imaging with electromagnetic fields in the microwave band has been mainly motivated by certain deficiencies in current screening and diagnostic practices based on X-ray mammography. In this thesis the feasibility of microwave radiometry as a modality for early-stage breast cancer detection has been investigated based on the tumor over-temperature rationale. The goal of this work is to establish the rationale for the application of microwave radiometry for breast cancer detection and to provide the basis for setting-up measurements on patients. Basing on electrical and thermal properties of breast tissue available in the literature I developed a numerical model to predict the radiometric output when a contacting antenna is scanned on the breast surface. For this reason, a full 3D model that relates radiometric data to the temperature difference between normal and malignant breast has been developed in order to predict the radiometric visibility of tumors. Then, I found that the deformation by a cooled antenna pressed against the breast lowers the distance of a subsurface tumor from the contacted surface thus improving the tumor radiometric visibility. I showed this result modeling breast deformation, temperature distribution and corresponding radiometer output both in the presence of a tumor and in its absence. Two patch antennas have been designed to be matched to a multilayer model of the breast. The antennas have been measured on volunteers in a preliminary small-scale experimental study. By estimating the antenna reflectivity I derived a requirement on the residual temperature when non-ideal radiation balance radiometer and antenna are considered. Some measurements with the "Tor Vergata" radiometer are presented. The radiometric resolution has been characterized when a matched load immersed in a water bath is connected to the input of the radiometer. A breast phantom and a thermal anomaly imitator for the mammary gland have been developed. The results of phantom measurements give positive indication on the feasibility of thermal spot detection by our radiometer.