Research On Safety Assessment Of Electromagnetic Exposure Of Radio Frequency Cosmetic

With the gradual application of radio frequency technology in the field of cosmetic,radio frequency cosmetic has become a new choice for facial rejuvenation.When RF electromagnetic field acts on human body,it will generate corresponding induction electric field and magnetic field near the applied position of human tissue.Long time exposure to the electromagnetic field will also affects the human nervous system and immune system,and even causes genetic material damage that is difficult to recover.Different types of radio frequency cosmetic instrument use different kinds of frequencies and electrodes,therefore,whether the radio frequency electromagnetic field produced by radiofrequency cosmetic electrode will cause damage to human health is gradually concerned.This paper introduced the research progress of radio frequency cosmetic instrument at home and abroad,including the electrode type and clinical safety of radio frequency cosmetic instrument.Through the study of the literature at home and abroad,it was found that the research on the safety of radio frequency cosmetic instrument at home and abroad mainly focused on the effectiveness and safety of the visible range,such as whether there will be scald,and sequel,etc.There is no study on the effect of electromagnetic exposure on human body.The calculation principle of electromagnetic field and specific absorption rate（SAR）and the selected numerical analysis method were expounded.This study selected fractional radio frequency that is commonly used in clinical and three common frequencies 1MHz,6MHz and 40.68MHz as research subject.A three-dimensional adult human body model,with a seven layers head model and the electrode model were established in COMSOL.Through the analysis,the heating mechanism of the electromagnetic field produced by the RF electrode in the human body and the multi-field coupling mechanism between the electromagnetic field and the thermal field were clarified.The relative permittivity and conductivity of human tissues were calculated by using the fourth-order Cole-Cole model.the distribution of electric field intensity,SAR and temperature in human head and brain under three different frequencies were calculated,and the safety assessment was carried out by comparing the calculated results with the restrictions specified by International commission on non-ionizing radiation protection（ICNIRP）.The results showed that for the electromagnetic exposure produced by fractional radio frequency cosmetic electrode,the maximum of the electric field intensity under three frequencies in brain was 2.78V/m,accounting for 9.9%of the ICNIRP guidelines,the maximum of SAR under three frequencies in brain was 1.88×10^-6W/kg,which was far less than 2W/kg of ICNIRP guidelines.The electric field intensity and SAR were within the safety restrictions specified by ICNIRP no matter what frequency,and the temperature in brain was the same as the normal body temperature 37℃,which indicated that the electromagnetic exposure is safe for human body.But for patients receiving treatment,certain protective measures must still be taken to protect against excessive magnetic field strength.