Basic Biophysical Principles of Resurfacing of Human Skin by Means of the Carbon Dioxide Laser

摘要

ABSTRACTThis discussion analyzes the biophysical effects of superpulsed, ultrapulsed, and swept-beam carbon dioxide lasers in the removal of the outer layers of skin for the purpose of facial resurfacing. It presents the differences in mode of operation among these systems, and their comparative advantages and disadvantages. The history of laser facial resurfacing, the characteristics of an ideal resurfacing laser, the importance of transverse electromagnetic mode, principles of minimization of thermal damage, the concept of ablation threshold, and the effect of pulse duration on thermal damage to adjacent tissue are discussed. The analysis is based upon some simplifying assumptions about the structure of epidermis and dermis, and the results are compared with those from empirical measurements, presenting a rational foundation for understanding the important phenomena of laser ablation of skin.