"Hypericin actually has a 10 times higher phototoxicity -- but it lasts only 10 hours."
The researchers have run tests on dogs at a local veterinarian clinic and were able to detect one case of cancer. They plan to continue their work on hamsters.
Once cancer has been identified, "photodynamic-treatment " once again, using light rays to target the cells can help kill the disease. An orange light forces hypericin to release oxygen "singlets" and decompose cancerous cells.
A second study involves the use of a "diffused spectroscope" to study melanoma, or skin cancer. Researchers developed the device, which is patented, to "inject" light into skin, where it is modified, then returns. Analysis of the light that comes back provides key information about the skin, says Rawicz. The project is being funded by a grant from the B.C. Science Council.
Measuring light is the key to another of Rawicz's group projects -- a dental color analyzer, which he expects to soon produce commercially. The analyzer allows for a precise match of dental material for reconstructive work on teeth, which, like skin, are translucent.
"Our impression of color is not only based on the reflection of light, but on the process that occurs when light enters the tooth it bounces and only partially comes out. We found a way to measure only the light which exits. In the same way, we can precisely measure the pigmentation of the skin and more easily diagnose the presence of melanoma."
Rawicz says all of the group's projects grew from research towards the
development of an artifical eye, which he began several years ago. "We've simply taken what we've learned about vision, perception and color and applied those things to other areas," says Rawicz, whose company is a founding member of the Optical Processing and Computing Consortium of Canada. Rawicz has also been ins
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Contact: Marianne Meadahl
marianne_meadahl@sfu.ca
604-291-4323
Simon Fraser University
6-Feb-1998