PHOTODYNAMIC THERAPY IN DERMATOLOGY

Abstract

Photodynamic therapy (PDT) is a treatment modality involving the administration of a photosensitizing compound and the accumulation of the sensitizer molecules in the target cells, followed by selective irradiation of the lesion with visible light. The combination of two individually non toxic elements, drugs and light, is responsible for the PDT-mediated destruction of tissues.

Photosensitizing compounds are taken up by most normal and malignant cells, but retained longer in certain tissues, especially in tumours and rapidly proliferating cells. The quality of the photosensitizer is important for the efficacy of photodynamic treatment. Chemical purity, capability of localizing specially in neoplastic tissues, short time interval between administration of the drug and its maximal accumulation in the tumor, short half life and rapid clearance from normal tissues, activation at wavelengths with optimal