Study On Thermal Effect Of Human Surface Tissue Excited By Electromagnetic Field

Noninvasive radiofrequency hyperthermia(RFH)technology has the advantages of low side effects and high efficiency.It can produce local high temperature at the target of human biological tissue,and then realize the DNA inactivation or thermal ablation of target cells in tissue.This technology has a wide application prospect in the thermal ablation of target cells in human biological tissue.However,the existing studies have less consideration on the influence parameters causing the temperature change of skin tissue target,and lack of comprehensive consideration of the joint influence of electromagnetic excitation parameters and human body differences on the thermal effect of human skin tissue,which leads to the reduction of the calculation accuracy of human skin tissue thermal effect model.At the same time,due to the small number of RF hyperthermia influence parameters and low model accuracy,it is difficult to effectively and accurately regulate the target temperature of human skin tissue,which is also easy to lead to human skin tissue hyperthermia accidents.Therefore,the effects of electromagnetic excitation amplitude and frequency,electrode size,hyperthermia time,target depth and fat thickness on human skin tissue target temperature are considered,this study focuses on the evolution law of human skin tissue target temperature;;The synergistic and antagonistic mechanisms of different influencing parameters on the target temperature of human skin tissue are discussed and analyzed;Based on the synergistic and antagonistic mechanism between different influence parameters,a thermal effect model of human skin tissue is proposed.Firstly,the RF hyperthermia model of human skin tissue is designed based on sim4 life simulation platform;The quasi-static equation and mesh generation method for calculating the physical field of human skin tissue under electromagnetic excitation are discussed;The action mode and mechanism of electromagnetic excitation in human biological tissue are analyzed;The heat dissipation process generated by blood perfusion in human tissue is designed to provide support for the analysis of electromagnetic excitation on the target temperature of human skin tissue.Secondly,the specific absorption rate(SAR)of human tissue under RF hyperthermia is determined to be within the safety limit by calculation.On this basis,the effects of different parameters such as electromagnetic excitation amplitude and frequency,RF electrode size,hyperthermia time,target depth and fat thickness on the target temperature of human skin tissue are studied;The relationship between different parameters,electric field intensity and current density and the target temperature of human skin tissue is constructed,and the evolution law of target temperature of human skin tissue under the action of different parameters,electric field intensity and current density is analyzed.Finally,the study revealed the synergistic and antagonistic mechanism of different parameters such as electromagnetic excitation amplitude and frequency,electrode size,hyperthermia time,target depth and fat thickness on the thermal effect of human skin tissue.Based on the synergistic and antagonistic mechanism between different parameters,a mathematical model of thermal effect of human skin tissue is proposed.Combined with finite element analysis and radiofrequency thermal ablation test,the calculation accuracy of the mathematical model of thermal effect of human skin tissue is verified(more than 97.5%),which provides a reference for a better understanding of the thermal effect mechanism of human skin tissue under the joint action of multiple factors and the optimization of radiofrequency thermal ablation technical parameters.