Photodynamic therapy is a non-thermal technique that uses light and not heat from light, to induce tissue damage and initiate the body to form a repair response to replace the damaged tissue. This occures through numerous standard steps in a clinical setting.
Administration of a photosensitizing drug, which becomes retained by tissue, including the malignant or diseased or damaged skin/tissue. The light from the therapy source, which can be controlled, is directed towards the agent, and activates the drug to form a cytotoxic oxygen species and free radicals. These molecules subsequently act on their surrounding tissue, causeing apoptosis/necrosis, death of cells, vascular damage, thereby decreasing that tissues access to blood and leading to death, and recruitment of inflammatory cells, like T cells and macrophages that can clear the area of foreign and malignant cells.
Photodynamic therapy treatment is as follows: Patients are selected, and certain people with specific infections are treated to prevent a flare (e.g. herpes). The skin is prepared and aminolevulinic acid is appplied, and allowed to penetrate and convert to its active form through time. Light at a specific wavelength to the drug is applied. Subsequently suncreen is used and the patient must follow-up with their physicians.
Light Sources for Photodynamic Therapy
Actinic Keratoses and Photodynamic Therapy
Sebaceous Hyperplasia and Photodynamic Therapy
Future Uses of Photodynamic Therapy