What Is PDT
Photodynamic therapy (PDT) is a procedure whereby a topical medication is applied to the skin which act as a photosensetiser followed by exposure to selected forms of light .
(PDT) was first medically used for the treatment of skin cancer in 1905 . At the time, a variety of compounds that preferentially concentrate in tumour cells, and could be activated by light leading to selective and localized destruction of cells were experimented on.
In 1990 topical 5-Aminolevulinic acid (ALA) was introduced for use in PDT . In 1999, 5-ALA received approval by FDA for the treatment of multiple actinic keratosis .Since then, world- wide research led to the successful use of PDT for the treatment of a variety of dermatological conditions.
How does it work
The photosensetising medication (ALA) is selectively absorbed by certain skin structures and lesions such as sebaceous glands (the main problem in acne ), sun damaged cells, actinic keratosis(pre cancerous lesions) and certain types of skin cancer. one or two hours following the application of the medication, the skin is exposed to certain forms of light . The light leads to the activation of the medication . A cascade of chemical reactions follow that lead to the destruction of the infected sebaceous glands ,sun damaged , pre cancerous and cancerous skin cells. The inflammation and skin peeling also leads to new collagen production and a much healthier looking skin.
The effectiveness of PDT is subject to many variables. These include dose of MLA or ALA, incubation time, penetration through targeted skin (affected in turn by skin thickness in the area treated, degree of sun damage, presence of inflammation such as psoriasis, exfoliation of the area prior to treatment etc.). It is also largely affected by the dose and wavelength of the light source used (PPIX is maximally activated at the wavelength 409 nm with smaller peaks at 509,544,584).
The trearment takes about 2 hours. moderate redness and swelling is expected the first 2 days followed by gentle peeling of the skin . If the treatment is done for active acne, mild excescerbation may follow the treatment. When doen for mild to moderate sun damage one treatment is usually required. More treatments are usually needed for active acne and skin cancers.
Can be used for
- Active acne/acne scarring
- Sebaceous hyperplasia
- Sun damaged skin
- Simple photo rejuvenation
- Certain types of skin cancer.