Early detection of breast cancer is crucial as death rate amongst the women due to breast cancer is on the rise. The gold standard for breast cancer detection is mammography. Radiation exposure and rupture of the tumour encapsulation during compression are risks associated with mammography. This provides the motivation to explore microwave radiometry, a passive and non-invasive technique for early-stage screening of breast cancer. In this technique, information about internal body temperature patterns is measured by gathering thermal radiation from the human body in the microwave regime. The underlying assumption is that early-stage malignant tumour has higher temperature than normal tissue due to the higher proliferation rate.
However, passive measurement of tissue temperature up to several cm deep inside the tissue is a non-trivial task. The thermal sensitivity and stability of the radiometer are influenced by the system architecture. Dicke-type medical radiometers reported in literature require off-line calibration which is tedious and time consuming. Furthermore, due to the narrow clinical temperature range (35-42 ℃), it is difficult to realize precision hot and cold noise sources with stable excessive noise ratio (ENR) over 1-4 GHz. In this talk, I propose to design and implement an architecture for on-line calibration of the fluctuations in system input reflection coefficient, gain and noise temperature. The proposed architecture will be realised at two frequency bands to extract depth information of the detected thermal anomaly. The performance of the proposed architecture and depth estimation algorithms will be assessed using a compact dual-band antenna which will be designed and optimized for this application. The sensitivity and stability of the developed dual-band radiometer will be assessed on phantoms mimicking human breast tissues.