Laser Technique Shows Cancer on Inner Layers of Skin

Author:  Doshi Ojus

Date:  June 2007

Summer beach-goers soaking up the sun without wearing sunscreen can rest a little easier. Scientists at Duke University have developed a device which uses two lasers to obtain high-quality images up to a millimeter under the skin. Both researchers and doctors hope to use the device to make diagnosis of cancerous skin cells, or melanomas, a non-invasive process.

Under the current procedure, "the doctor sees a pigmented lesion and decides if it is dangerous or not. If she cuts it out, she can see how regularly shaped it is and match it up with patterns that [she's] used to," explained Warren. S. Warren, the James B. Duke Professor of chemistry, radiology and biomedical engineering, and director of Duke's new Center for Molecular and Biomedical Imaging, whose group developed the device.

Instead of surgically removing a skin lesion, analyzing it via microscope is one developing option. But current microscopy techniques, according to Warren, cannot generate a good biological picture of a cancerous skin growth. "Today the problem is that you can only see a few microns deep into the tissue," he remarked. "What we're doing is a different kind of microscopy. By using infrared lasers, we're forcing in two photons instead of one."

The group's device uses lasers pulsing on the order of femtoseconds (or one quadrillionth of a second) at two different wavelengths to make the biological molecules melanin and hemoglobin glow. External microscopes capture the glowing nature of the molecules, and computers generate a three-dimensional image of the cellular characteristics of the targeted region of skin.

Currently the device takes up all of a four foot by twelve foot table, but this was for the general experimental stage. In its final stages, with defined parameters, the device could be as big as a textbook, Warren mentioned.

Warren looks to work with Dr. James Grichnik, a Duke dermatologist, to implement the device in clinical trials.

Grichnik commented that in comparison to confocal microscopy, the type of microscopy used today which relies upon a single wavelength of light, Warren's technology uses multiple wavelengths and has a higher likelihood of producing more information.

"It should be wonderful technology, particularly for dermatology," Grichnik said. "We need to see what it does, and see what it does well. Once you identify its relevance to malignancy, you can come back with a full-bore clinical trial."

Written by Ojus Doshi