Alternative / supplemental breast imaging methods tested

Dartmouth physicians and engineers are collaborating to test three new imaging techniques to find breast abnormalities, including cancer. Results from the first stage of their research, information about the electro-magnetic characteristics of healthy breast tissue, appears in the May 2004 issue of Radiology, the journal of the Radiological Society of North America.

The interdisciplinary team, which includes researchers from Dartmouth’s Thayer School of Engineering and Dartmouth Medical School working with experts at the Norris Cotton Cancer Center and the Department of Radiology at Dartmouth-Hitchcock Medical Center (DHMC), is developing and testing imaging techniques to learn about breast tissue structure and behavior. The techniques are electrical impedance spectral imaging (EIS), microwave imaging spectroscopy (MIS), and near infrared (NIR) spectral imaging.

“This study offers the foundation for future research and clinical trials,” says Steven Poplack, associate professor of radiology and OB/GYN at Dartmouth Medical School, doctor of diagnostic radiology and Co-Director for Breast Imaging/Mammography at DHMC, and the lead author of the paper. “We’re establishing normal ranges for healthy breast tissue characteristics in order to more easily recognize the abnormalities.”

The study of 23 healthy women offers baseline data from the three techniques. The methods are not invasive or particularly uncomfortable for participants, and they all provide detailed information about different properties of breast tissue.

* EIS: This painless test uses a very low voltage electrode system to examine how the breast tissue conducts and stores electricity. Living cell membranes carry an electric potential that affect the way a current flows, and different cancer cells have different electrical characteristics.

* MIS: This exam involves the propagation of very low levels (1000 times less than a cell phone) of microwave energy through breast tissue to measure electrical properties. This technique is particularly sensitive to water. Generally, tumors have been found to have more water and blood than regular tissue.

* NIR: Infrared light is sensitive to blood, so by sending infrared light through breast tissue with a fiber optic array, the researchers are able to locate and quantify regions of oxygenated and deoxygenated hemoglobin. This might help detect early tumor growth and characterize the stage of a tumor by learning about its vascular makeup.

Keith D. Paulsen, Professor of Engineering and a co-author of the study, is the principal investigator of this research program, which is funded by the National Cancer Institute. Other authors on the paper include Alexander Hartov, Paul M. Meaney, Brian W. Pogue, Tor D. Tosteson, Margaret R. Grove, Sandra K. Soho, and Wendy A. Wells, all associated with Dartmouth’s Thayer School of Engineering or Dartmouth Medical School.