Abstract
Commercially available ruby laser systems have long pulse duration of 2 msec and have produced excellent effects in the treatment of superficial pigmentated diseases, but not enough effects in patients with deep lesions. We have recently used the shorter pulse duration ruby laser, having pulse duration of 200-400 microsec, in the treatment of pigmentated diseases of the skin, and had favorable results. In the present study, histological changes in the skin taken on surgery after the short pulse ruby laser irradiation were compared with those after conventional long pulse duration irradiation at pulse duration of 2 msec. The short pulse laser irradiation produced basically similar changes in the basal cell of the epidermis to those produced after long pulse laser irradiation, but the former was more selectively effective than the latter for intradermal melanins. Especially, with short pulse duration, low-energy level (about 10J/cm2) laser irradiation, “crater-like degeneration” was observed in the area where melanins were present in the upper dermis layer, despite of little changes in basal layer of epidermis.
