In vivo dynamic thermal imaging of skin radiofrequency treatment.

In recent years, popularity of radiofrequency (RF) has increased significantly. They are characterized by a low risk of complications and relatively high effectiveness. RF use high-frequency currents causing oscillating motion of ions resulting in temperature rise stimulating skin regeneration processes. The aim of this work was the thermographic evaluation of the skin exposed to RF of different intensity. The dynamic thermal imaging was used to study the temperature of the skin exposed to RF. The research was carried out in two locations with different adipose tissue content: abdomen (ROI1) and forearm (ROI2). In the ROI1 area, RF was applied at nominal power range from 250 to 1750 W, while in ROI2 area: from 250 to 1000 W. The obtained thermographic data were fitted to exponential functions. A clear dependence of obtained thermokinetic parameters with the anatomical location of exposure to RF was demonstrated. Thicker layer of adipose tissue directly under the skin resulted in obtaining higher maximum temperatures of the skin surface during the procedure (maximum obtained temperature equaled 40.8°C). The temperature of the skin under the head of the device does not translate to subjective patient experiences. In anatomic locations filled with less adipose tissue mass, tolerance to RF is much lower. The dynamics of skin temperature changes, after the RF treatment, can be described by means of a single exponential function where the key parameter is the time constant t1 defining the dynamics of skin temperature changes. The depth of the RF influence is slightly correlated with the RF power.