3. Enhance

For most types of photodynamic therapy (PDT), a special drug called a photosensitizing agent is put into the bloodstream. Over time, it is absorbed by body tissues. The drug stays longer in cancer cells than in normal cells.

Photosensitizing agents are turned on or activated by certain types of light. When cancer cells that contain the photosensitizing agent are exposed to light from an argon laser, it causes a chemical reaction that kills them. Light exposure must be carefully timed so that it’s used when most of the agent has left healthy cells but is still in the cancer cells.
PDT is sometimes used to treat cancers and pre-cancers of the esophagus, bile duct, bladder, and certain kinds of lung cancer that can be reached with endoscopes.

It is also being studied for use in other cancers, such as brain, pancreas, and prostate. Researchers are looking at different kinds of lasers and new photosensitizer drugs that might work better.