Photodynamic Therapy (PDT) is a medical treatment that uses light-sensitive drugs, known as photosensitizers, to target and destroy cancer cells. When these drugs are exposed to a specific wavelength of light, they become activated and produce a form of oxygen that kills nearby cells. This therapy is often used for certain types of skin cancer and other localized tumors. The procedure typically involves applying the photosensitizer to the affected area and allowing it to absorb for a few hours or days. After this, a light source is directed at the area, triggering the drug's action. PDT is minimally invasive and can lead to fewer side effects compared to traditional treatments like chemotherapy or radiation therapy.