Optical Biopsy of Breasts

U of Ideas in Medicine ó October 1998 University of Illinois at Urbana-Champaign

Contact: James E. Kloeppel, Physical Sciences Editor (217) 244-1073; kloeppel@uiuc.edu

BREAST-CANCER DETECTION

Optical biopsy would be fast, painless and inexpensive

CHAMPAIGN, Ill. -- An optical mammography technique developed at the University of Illinois now is being tested for more powerful diagnostic capabilities.

The technique -- which uses near-infrared light to probe breast tissue for hidden growths -- has the potential to distinguish between malignant and benign tumors, and could eliminate the need for patients to undergo painful needle biopsies or expensive magnetic resonance imaging procedures.

ìBreast cancer remains one of the leading causes of death and disfigurement in women,î said U. of I. physics professor Enrico Gratton, one of the scientists who invented the technique. ìThe best prognosis occurs when the tumor is caught while it is small. But early detection requires a reliable screening procedure.î

X-ray mammography, though commonly employed for breast cancer screening, suffers from a number of drawbacks that limit its effectiveness. ìThe procedure does not work well on younger women, whose breasts are radiologically dense,î Gratton said. ìAnd in women between the ages of 40 and 50, X-rays fail to detect nearly half of all cancerous tumors.î

Another disadvantage of X-ray mammography is that the procedure yields many ìfalse positivesî -- anomalies that could be cancer, benign cysts or simply pockets of dense tissue.

ìSuch false positives can create tremendous psychological stress for the patient while waiting for additional tests or biopsies to be performed,î Gratton said. ìWe wanted to develop a safe and reliable technique that could both identify tumors and significantly reduce the number of false positives.î

Grattonís technique is similar to X-ray mammography, but uses infrared light instead of X-rays. The infrared light penetrates the breast and detects changes in the concentrations of blood vessels.

ìMost tumors are associated with rapid cell growth, with an attendant increase in the number of blood vessels feeding the tumor,î Gratton said. ìBy sending a pulse of light into tissue, and then measuring the time it takes to travel through the tissue, we can tell how much light is scattered and how much is absorbed. This provides distinctive clues to the location and identity of hidden growths.î

Compared to X-ray mammography, the new blood-mapping procedure ìis less risky and can be applied to a larger segment of the female population,î Gratton said. ìAnd because we donít need to compress the breast as much, our procedure also causes less physical discomfort.î

To better assess the optical technique, Gratton and his colleagues in the universityís Laboratory for Fluorescence Dynamics are collaborating in a clinical trial currently under way at Robert Roessle Hospital and Tumor Institute at Humboldt University in Berlin, Germany.

Preliminary results have been very encouraging, Gratton said. ìThere appears to be a strong correlation between the infrared signature and the type of tumor. Used as an optical biopsy, our procedure would be fast, painless and extremely accurate.î

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