NIR technique identifies breast cancer and therapy response

New optical imaging technology developed at Tufts University could give doctors new ways to both identify breast cancer and monitor individual patients’ response to initial treatment of the disease.

The non-invasive technology, developed at the university’s School of Engineering, uses near-infrared (NIR) light to scan breast tissue and then applies an algorithm to interpret that information.

According to a statement, differences in light absorption enable the identification of water, fats and oxygen-rich and oxygen-poor tissue, the primary structures in breast tissue.

‘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 lead researcher Sergio Fantini, professor of biomedical engineering.

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.

Because it does not use ionising radiation, the NIR technique can be applied multiple times over a short period without risk of radiation exposure, Fantini said. Another advantage of the technology is that, unlike other breast-imaging methods, it can obtain functional real-time images of metabolic changes, such as levels of haemoglobin concentration and oxygenation.

‘It’s been reported that patients who respond to breast cancer chemotherapy show a decrease in haemoglobin and water concentration and an increase in lipid concentration at the cancer site,’ added Fantini. ‘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. For example, it could help determine if a patient is responding to neoadjuvant chemotherapy administered to shrink a tumour before surgery.’

Optical mammography is also said to be more comfortable than traditional mammograms. The patient’s breasts are only lightly compressed between two horizontal glass panels and then illuminated by NIR light. A specialised software program displays real-time images of the breast as the optical system scans back and forth. A light detector within the system displays the intensity of the NIR beam as it is transmitted through the breast.

By using an algorithm based on the optical information, the technology generates breast images using the intensity of the transmitted light. The images are displayed automatically and can be read soon after the procedure, as is the case with X-ray mammograms. Furthermore, the technology has been designed to be packaged into compact, portable and handheld devices.

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

The optical imaging was successful in enabling the team to identify cancerous tissue. ‘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 $3.5m (£2.1m) grant from the US National Institutes of Health, is now under way at Tufts Medical Center in Boston.