Photodynamic laser therapy; Photodynamic tumor therapy
Photodynamic Therapy (PDT) uses the action of visible, low energetic light on a photosensitizer to activate its destructive potential in a target tissue. PDT is a selective treatment modality since the photosensitizer shows preferential accumulation in target (e.g., tumor) cells and the light application can be restricted to the target area. By light activation the photosensitizer forms cytotoxic compounds, mainly reactive oxygen species (ROS), destroying the target. The emission of fluorescence light is employed in fluorescence diagnosis for tumor diagnosis. PDT is applied for malignant and several nonmalignant diseases.
Photodynamic effects have been known for a long time from substances enhancing the healing effect of sunlight. It lasted until 1904 when the term “photodynamic” was used for light-induced cytotoxic action and fluorescence of a photosensitizer. Modern...