Traditional X-ray mammography creates a breast image by passing high-energy ionizing radiation through a highly compressed breast to film on the other side. Though this process has warned thousands of cancer, it is far from perfect, says Susan Hagness (center).

An assistant professor of electrical and computer engineering and biomedical engineering, Hagness is working with Associate Professor of Radiology Frederick Kelcz (right) to develop a low-cost, computer-based microwave tumor-detection system that could improve early detection and eliminate the trauma of unnecessary biopsies. In addition, microwave imaging carries no danger of ionizing radiation exposure.

Microwaves interact with human tissues primarily according to water content. Because malignant tumors have a much higher water content and more vascularization than normal breast tissue, microwaves can provide the basis for a highly sensitive detection system. In Hagness' research, low-power microwave pulses interrogate the tissue. Cancerous lesions back-scatter the pulses, producing a microwave echo. Measuring those echoes enables Hagness to develop a 3-D image of malignant tumors.

Graduate student Kristen Leininger (left), Hagness and Kelcz collect data on breast tissue removed through hundreds of excisional biopsies at University of Wisconsin Hospital and Clinics. The information will be used to develop a microwave sensor capable of detecting very small lesions and discriminating between malignant and benign cases. The system will include a small flat panel containing an array of miniature antennas placed gently on the breast's surface and will be inexpensive enough to be widely accessible in health care.

Photo by Bruce Fritz