Photodynamic Therapy

Photodynamic Therapy (PDT) is a technique recently introduced for treating superficial precancerous skin lesions: actinic or solar keratoses, superficial basal cell carcinomas and spincocelular carcinomas in situ or Bowen's disease (Skin Cancer).

Photodynamic therapy is principally used to treat multiple lesions over extensive areas or as prevention for large areas where there is a possible risk of cancer. Cosmetic results are better than those obtained with conventional destructive techniques, which makes it the appropriate choice for localized cases in aesthetic areas.

The action of photodynamic therapy may be regarded as a physical-chemical combination. It is based on the excitation of a photosensitizer by a source of visible light to produce an oxygen activated cytotoxic agent in the cancerous cells which destroys them. Its destructive action is therefore highly selective.

The chemical substance employed is a derivate of levulinic acid: aminolevulinic acid (ALA) or methyl aminolevulinate (MAL). It induces the accumulation of porphyrins in the cell nuclei. Thissubstance is absorbed by the affected (precancerous or cancerous) cells and remains in them longer than in the healthy neighboring cells, thereby enabling the treatment to be repeated as often as required without any risk.