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Presenter: Dr. Susan C. Hagness - Electrical and Computer Engineering, University of Wisconsin-Madison
Supervisor:

Date: Wed, October 30, 2002
Time: 19:00:00 - 20:00:00
Place: Clearihue Bldg., Room CLE 127

ABSTRACT

Abstract

According to the American Cancer Society, early detection of breast cancer greatly improves a woman's treatment options and her chances for successful treatment and long-term survival. While x-ray mammography is currently the most effective clinical method for detecting cancer before physical symptoms develop, its limitations are well known. Consequently, there is an ongoing search for alternative techniques that night more consistently detect small cancers and better distinguish them from benign breast conditions.

The principles of a novel microwave breast imaging technique will be described in this talk. Ongoing dielectric-properties measurements on breast biopsy, lumpectomy, mastectomy, and reduction mammoplasty specimens are providing insights about the contrast mechanisms that can be exploited at microwave frequencies. Preliminary data suggesting a significant contrast in the dielectric properties of normal and malignant tissue provides a compelling rationale for the development of microwave detection techniques.

Our approach relies on radar techniques similar to those used to detect buried land mines. Detection and localization of a malignancy is achieved by transmitting very low-power, short-duration microwave signals into the breast and processing the backscattered signals collected at multiple spatial locations. The processing techniques involve focusing the backscattered signals using both temporal and spatial dimensions. The resulting microwave image displays backscattered signal energy as a function of location in the breast. Locations corresponding to malignant tumors are associated with large energy levels in the image because of the significant dielectric-properties contrast between malignant and normal tissue.

The effectiveness of this approach is demonstrated theoretically using anatomically realistic numerical breast phantoms and experimentally using physical breast phantoms. Our studies to date suggest that this novel microwave imaging approach offers the potential of a non-ionizing, non-invasive breast screening technology capable of reducing the rate of false negatives and false positives associated with conventional x-ray mammography, especially for challenging cases involving radiographically dense breasts or tumors near the chest wall or underarm. The predicted safety, comfort (no breast compression), low cost, and ease of use of this method should greatly increase the effectiveness of screening programs.