Microwaves an alternative to mammo for breast cancer screening?

While screening modalities such as mammography are effective at detecting early breast cancers, they can be problematic since they subject patients to ionizing radiation, as well as discomfort caused by compressing the breast in order to produce diagnostically useful images.

One possible alternative, as described in an article in the current issue of the journal Review of Scientific Instruments, could be the use of microwaves.

According to Neil Epstein, a postdoctoral fellow at the University of Calgary in Canada, and his colleagues--engineering professor Paul Meaney of Dartmouth College's Thayer School of Engineering and Keith Paulsen, director of the Dartmouth Advanced Imaging Center and the Robert A. Pritzker Professor of Biomedical Engineering and Professor of Radiology at the Geisel School of Medicine at Dartmouth College--microwave imaging relies upon the differences in dielectric properties in cancerous and normal tissue.

In the technique described by the researchers, the breast is suspended in a liquid bath and surrounded by an array of 16 antennas. Each antenna illuminates the breast individually with a low power microwave signal providing data used to produce a 3-D representation of the breast, including the location of cancerous and normal tissue.

"The iterative image reconstruction algorithm computes what the dielectric property distribution must have been to generate the measured signal patterns," Epstein said in an announcement. "It is quite similar to X-ray computed tomography, where the target is radiated from all of the surrounding directions and the data is synthesized to create an image of the internal structures."

Though microwaves systems can't offer the spatial resolution provided by mammography, Epstein said, it does provide better specificity. "Researchers are realizing that this lack of specificity is a significant limitation for conventional imaging techniques and are looking for alternative ways to enhance it. Microwave imaging could fill this niche, possibly in combination with other modalities," he said.

A Northeastern University researcher also recently began investigating the use of microwave radar as a tool to better see and diagnose breast cancer. Engineers at Northeastern are working on a device that performs digital breast tomosynthesis at the same time it takes microwave images.

Digital breast tomosynthesis is effective in reducing patient recalls and detecting cancers when compared to digital mammography, but is even more effective when used to screen women under the age of 50, according to a study published in October in the Journal of the National Cancer Institute.

To learn more:
- see the article in Review of Scientific Instruments
- see the announcement