PDT or Photodynamic therapy is a treatment that uses special drugs, called photosensitizing agents, along with light to kill cancer cells. Depending on the part of the body being treated, the photosensitizing agent is either put into the bloodstream through a vein or put on the skin. Over a certain amount of time the drug is absorbed by the cancer cells. The drugs are then activated by certain kinds of light which is applied to the area being treated. The light causes the drug to react with oxygen, which forms a chemical that kills the cells. PDT might also help by destroying the blood vessels that feed the cancer cells and by alerting the immune system to attack the cancer.
