Susan Hagness, Ph.D. Assistant Professor, Department of Electrical and Computer Engineering University of Wisconsin (RG-99-0004) Madison, WI Confocal Microwave Imaging for Breast Cancer Detection X-ray mammography is the most effective imaging method for detecting non-palpable early-stage breast cancer. However, despite significant progress in improving mammographic technique, persisting limitations result in a relatively high number of false negatives and false positives. Thus, techniques that image other physical tissue properties are under investigation. This project is aimed at investigating confocal microwave imaging for early-stage breast cancer detection. This novel approach represents an adaptation and application of the principles of ultrawideband radar technology and confocal optical microscopy. The proposed tumor-detection system exploits the large dielectric contrast between normal breast tissues and malignant tumors at microwave frequencies. A miniaturized antenna array will transmit a focused low-power pulsed microwave signal into the breast and collect the backscattered energy. The focus will be achieved synthetically by postprocessing the backscattered waveforms received at each sensor element. This will permit systematic scanning of the sensor's focus from point to point within the breast, allowing three-dimensional image formation. The specific aims are: To develop a measurement protocol for characterizing the dielectric properties of freshly excised malignant and benign breast tissue at microwave frequencies. To synthesize the signal-processing algorithms needed to create a three-dimensional microwave image of the internal breast tissue from the microwave backscatter data and to distinguish between malignant and benign lesions. To design an ultrawideband microwave antenna-array sensor that meets the necessary signal-to-noise and dynamic range requirements of the confocal microwave imaging system. The proposed research has intrinsic scientific and engineering interest independent of the particular clinical application to breast cancer detection. Confocal microwave imaging may prove to be useful for other biological imaging applications. The long-term objective of this work is to develop and expand the use of nonionizing electromagnetic techniques for a variety of diagnostic and therapeutic biomedical applications. Copyright 1998 The Whitaker Foundation 1700 North Moore Street, Suite 2200, Rosslyn VA 22209 (703) 528-2430     info@whitaker.org