After activation of the drug by the light emitted and a reaction with the oxygen present on the abnormal tissue, local destruction occurs to destroy the targeted abnormal cells without leaving a mark or scar.
The major advantage of PDT is its selectivity. Indeed, light used alone is not harmful just as the photosensitizer without the effect of light is not toxic. To induce the desired destruction reaction, a combined action of light, photosensitizer and oxygen is required. Thus, by optimizing the concentration of the photosensitizer and the dose of light emitted, it is possible to selectively destroy cells without reaching non-target cells.
Photodynamic therapy (PDT) is used mainly in the treatment of actinic keratoses but also for superficial (in situ) basal cell and squamous cell carcinomas. The Center de Dermatologie du Québec Métropolitain is the Canadian leader in photodynamic therapy (PDT).