SAN DIEGO -- To eradicate any cancer cells that may potentially remain after surgery or chemotherapy, many breast cancer patients also undergo radiation therapy. All patients experience unfortunate side effects including skin irritation, and sometimes peeling and blistering. Patients can also develop permanent discoloration of the skin and thickening of the breast tissue months, or even years, after treatment. There is currently no method to predict the severity of these acute and late effects, and even current evaluation of these effects are based on subjective scoring.

Researchers at the Beckman Laser Institute (BLI) and Medical Clinic, and the Department of Radiation Oncology at the University of California, Irvine are testing a new imaging device developed by start-up, Modulated Imaging Inc. (Irvine, CA). One of these studies is designed to monitor, quantify, and hopefully one day predict skin toxicity levels induced by radiation therapy. Anaïs Leproux, a post-doctoral researcher at BLI and lead author of the paper, will report the work at the OSA Biophotonics Congress: Optics in the Life Sciences meeting, held 2-5 April in San Diego, California, USA.

"We use visible and near-infrared light at very low power and project it onto the breast," said Leproux. "We are trying to characterize the skin damage during radiation therapy, especially for the treatment of breast cancer."
Using their new imaging technique, the project is aimed at using precision measurements to characterize skin toxicity of tissue exposed to radiation. By tracking these measurements throughout treatment, Leproux and her team hope to better understand the factors involved in skin damage and, hopefully, how to predict acute and late toxicities.

"The toxicity is basically the skin damage, a side effect from the radiation," said Leproux. "There are a wide range of side effects that we're observing; erythema, hyperpigmentation, discoloration, dry or wet desquamation. Necrosis can happen but is less common."

Erythema is the formal name for superficial reddening of the skin, and desquamation is skin peeling. Thickening of the skin is a common late side effect.

"The light is shined onto the breast tissue. When interacting with the skin; the light is scattered and some is absorbed," said Leproux. "The reflected light is detected by a camera. Basically, you're measuring the absorption and the scattering properties of the tissue."

More specifically, she and her group use eight different wavelengths of visible and near-infrared light from LEDs, measuring how much of each energy is absorbed by the skin. This provides them with a quantitative values indicative of skin health.

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