Optical Mammography IDs Breast Cancer

A novel noninvasive optical imaging technique could offer doctors new ways both to identify breast cancer and to monitor a patient’s response to initial treatment.

Developed at the Tufts University School of Engineering, the method uses near-infrared (NIR) light to scan breast tissue and identify the primary structures of breast tissue — water, fats and oxygen-rich and oxygen-poor tissue — based on differences in light absorption and the intensity of the transmitted light.

A specialized software program automatically displays real-time images of the breast as the optical system scans back and forth. As is the case with x-ray mammograms, the images can be read soon after the procedure.

An optical mammography image of hemoglobin oxygenation of a duct carcinoma in situ (DCIS), a breast cancer in the lining of the milk ducts that has not yet invaded nearby tissues. The boxed area corresponds to the cancer location and indicates lower values for hemoglobin oxygenation. For cancerous tissue associated with abnormal hemoglobin concentration and oxygenation, optical mammography can help diagnose breast cancer and also indicate how well a patient responds to chemotherapy. (Image: Dr. Sergio Fantini, professor of biomedical engineering at Tufts University)

"The consensus is that x-ray mammography is very good at detecting lesions, but it's not as good at determining which suspicious lesions are really cancer," said professor of biomedical engineering Dr. Sergio Fantini, who is leading the research effort. The Tufts NIR technique could complement standard mammography, particularly for women younger than 40 who may have dense breast tissue that tends to obscure detail in x-rays.

The method does not use ionizing radiation, so it can be applied multiple times over a short period without the risk of radiation exposure, Fantini said. Unlike other breast imaging methods, it can obtain functional real-time images of metabolic changes, such as hemoglobin concentration and oxygenation levels.

"It's been reported that patients who respond to breast cancer chemotherapy show a decrease in hemoglobin and water concentration and an increase in lipid concentration at the cancer site," Fantini said. “This suggests that NIR imaging can be valuable not only in diagnosing breast cancer but in monitoring individual response to therapies without requiring repeated x-rays.”

In collaboration with Dr. Roger Graham, director of Tufts Medical Center's Breast Health Center, and Dr. Marc Homer, chief of mammography at Tufts Medical Center, Fantini and his team conducted proof-of-concept tests to see whether their procedure could corroborate information gathered with x-rays on two patients who each had suspicious lesions in one of their breasts.

"The test results were compatible with what we found in the x-ray mammography," Graham said. "It was also painless for the patients and eliminated radiation exposure."

A five-year clinical study of the procedure, funded by a $3.5 million grant from the National Institutes of Health, is now under way at Tufts Medical Center in Boston. It will investigate healthy women, women with breast cancer, and women with benign breast lesions in an effort to examine the effectiveness of optical mammography in detecting breast cancer and distinguishing between malignant and benign tumors. It will also investigate optical mammography’s power to determine patients’ response to chemotherapy at the beginning of treatment.

For more information, visit: www.tufts.edu