Photodynamic Therapy:

Kevin Robinson, Senior News Editor

A relatively new technology called photodynamic therapy is revolutionizing the treatment of some types of cancer. In this treatment, a physician injects a patient with a photosensitive chemical. When activated by light, these chemicals combine with the oxygen in the tissue to kill the tumor. For reasons still not completely known, the drug stays in cancerous tissue longer than in healthy tissue, allowing doctors to selectively target the disease.
Most drug manufacturers are cooperating with photonics companies to develop the light sources for particular chemicals. (Generally these fall between 600 nm and the near-IR, but a few lie in the blue and green regions of the spectrum.) However, as the market matures and more drugs become available, alternative light sources may be a route to success.