Photo Dynamic Therapy (PDT) is a special non-surgical treatment that uses a naturally occurring amino acid solution called ALA(Amino Levulenic Acid) to activate a reaction with a specific light source. PDT can be used to treat areas of sundamage and aging skin, specific skin cancers, sunspots and acne. There are various protocols which involve waiting a period of time after applying the solution to the skin, often for 1-2 hours but sometimes longer. This waiting time is called the Incubation time and allows the solution to be absorbed fully by the skin cells being targeted. The treated skin is then exposed to a light source such as BBL, Excel V laser and then to LED light. You need to avoid sun exposure for 48 hours after PDT treatment and there can be quite a bit of skin reaction with redness and peeling.