With over 200,000 new cases reported last year, breast cancer now accounts for nearly one of every three cancers diagnosed in U.S. women. While great strides have been made in early detection, the conventional method of mammography is not failureproof: it has trouble imaging dense tissue, it may show suspicious areas where no malignancy exists, and radiologists interpreting the images can miss up to 15 percent of cancers. It's also uncomfortable, requiring each breast to be compressed between plastic plates, which can lead to bruising.
Susan C. Hagness wants to change all that. An assistant professor of electrical engineering at the University of Wisconsin-Madison, she is pioneering a novel detection technique that uses ultrawideband microwaves to image even the tiniest malignant tumors in the breast. Breast cancers show much more contrast at microwave frequencies than at the X-ray frequencies used for mammograms. Microwaves are also nonionizing, and the technique requires no breast compression.
The approach that Hagness and her group are developing relies on algorithms originally developed for radar signal processing. In the procedure, a woman's breast is surrounded by an antenna array, and each antenna in turn transmits a low-power microwave pulse into the breast and collects the backscattered signal. Using computer models and simple physical experiments, they have been able to clearly identify tumors as small as 2 mm in diameter. X-ray mammography, by contrast, typically can't detect lesions smaller than 0.5 cm, and if the breast tissue is dense, a 1-cm or larger lesion may not show up.
The technology is still in the research stage, Hagness cautions, and it may be years before clinical trials begin. But she is hopeful. "In my mind, breast cancer detection is one of the most important and most challenging engineering problems," Hagness says. "It's exciting to be working on something that has so much potential for saving women's lives."
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