Efficacy of Ablative Fractional Laser-assisted Photodynamic Therapy According to the Laser Density for Actinic Keratosis

For AFL pre-treatment, lidocaine/prilocaine (5%) cream (EMLA; Astra Pharmaceuticals, LP, Westborough, MA, USA) was applied to the treatment area under occlusion for 30 min

After the anaesthetic cream was removed, AFL therapy was performed using a 2940-nm Er:YAG AFL (Joule; Sciton Inc., Palo Alto, CA, USA) at 5.5% or 11% or 22% laser density with 350 µm ablation depth, level 1 coagulation and a single pulse

Immediately after AFL treatment, an approximately 1- mm-thick layer of MAL (Metvix, PhotoCure ASA, Oslo, Norway) was applied to the lesion and on 5 mm of surrounding normal tissue. Incubation time is 3 hours

After 3 hours of application with MAL, saline wash was performed and fluorescence imaging analysis was performed with ultraviolet examination light (model 31602,356 nm; Burton Medical Products Crop.) at 10 cm height above the base of each lesion. The red fluorescence (610 nm-700 nm) was separated and extracted by Matlab program and then used to measure the amount of 633 nm fluorescence of protoporphyrin IX.

After incubation for 3 hours, the dressing and cream were removed, and the area was cleansed with saline. The area was irradiated with a red light-emitting diode lamp (Aktilite CL 128; PhotoCure ASA, Oslo, Norway) with peak emission at 632 nm, placed 5 cm away from the skin surface, and a total light dose of 37 J/cm-2. All patients wore protective goggles during illumination.