For the implementation of PT, the PT group plaques that would not receive radiation were covered with thick cloth towels, while the healthy skin surrounding the treated plaques were coated with liquid petroleum jelly. Both patients and attendant were protected with special lenses with filter against UV light (Oakley Jupiter, USA). UV-B radiation was applied with the UV Endolamp 474 device (Enraf Nonius Company SA, Spain), 60 cm away from the plaque and in a perpendicular position. In session 1, the MED was calculated for each subject and used as the time of UV-B exposure. On each further session, the exposure time was increased by 25%, until the limit of 5 minutes.