The biothermomechanical behaviour of skin tissue under electromagnetic heating

Electromagnetic heating is widely used in medicaltreatments, such as microwave, radiofrequency, laser, etc. Recent advancesin these technologies resulted in remarkable developments of thermaltreatments for a multitude of diseases and injuries involving skin tissue.The comprehension of heat transfer and related thermomechanics in skintissue during these treatments is thus of great importance, and cancontribute to the further developments of these medical applications.Biothermomechanics of skin is highly interdisciplinary, involving bioheattransfer, burn damage, biomechanics and physiology. The aim of this study isto develop a computational approach to examine the heat transfer process,heat-induced mechanical response as well as the associated pain level, sothat the differences among the clinically applied heating modalities can bequantified. In this paper, numerical simulations with the finite differencemethod (FDM) was used to analyze the temperature, burn damage and thermalstress distributions in the skin tissue subjected to various thermaltreatments. The results showed that the thermo-mechanical behavior of skintissue is very complex: blood perfusion has little effect on thermal damagebut large influence on skin temperature distribution, which, in turn,influences significantly the resulting thermal stress field; for laserheating, the peak temperature is higher for laser with shorter wavelength,but the peak is closer to the skin surface; the thermal stress due to laserand microwave heating is mainly limited to the top epidermis layer due tothe exponential decrease of heat generation along skin depth; the thin (andcommonly overlooked) stratum corneum layer dominates the thermomechanicalresponse of skin tissue.