PDT is a special treatment aimed primarily at treating precancerous skin lesions (Actinic Keratoses). This treatment has also demonstrated benefits for acne and photoaging from sun damage. The treatment is performed in our office. A medicine called levulan is applied to the treatment area then allowed to soak in for one hour. After one hour, the medicine is activated with a special light called a Blu-U light. Damaged skin begins to react within 24 hours. The skin becomes red and irritated. By 7-10 days, the skin peels and returns to normal. Only the damaged areas react. Typically, this treatment is repeated 3 times over a 2-3 month period. When used for actinic keratoses (pre-cancerous lesions), this treatment is typically covered by insurance.