What is photodynamic therapy? Photodynamic therapy known as PDT is a treatment that uses a drug, called a photosensitizer and a blue light. When the photosensitizers are exposed to the blue light, they produce a form of oxygen that kills nearby cells.

 

How is Blue Light (PDT) used to treat cancer? A photosensitizing agent is injected into the bloodstream. The agent is absorbed by cells all over the body but stays in cancer cells longer than it does in normal cells. Approximately 48 hours after the injection most of the photosensitizing agent has left the normal cells but still remains in cancer cells, the tumor is exposed to the blue light. The photosensitizer in the tumor absorbs the light and produces an active form of oxygen that destroys nearby cancer cells. The Blue light needed to activate most photosensitizers cannot pass through more than about 1 centimeter of tissue so PDT is mostly used to treat tumors on or just under the skin or on the lining of internal organs.