心脏起搏器无线充电电磁暴露安全评估

Safety assessment of electromagnetic exposure for wireless charging of cardiac pacemakers

为准确地评估心脏起搏器无线充电工作过程中产生的电磁暴露安全性,使用基于有限元的COMSOL软件进行建模及仿真计算。构建人体头部组织、简易胸腔及心脏的模型,并且在无线充电系统工作频率设置为251 kHz时,得出了以上3个部位中产生的磁感应强度(B)、感应电场强度(E)分布,以及人体头部组织比吸收率(Specific absorptionrate,SAR)值的分布,将结果与国际非电离辐射防护委员会(ICNIRP)制定的限值进行比较。结果显示:人体头部中B值最大为0.337μT,占ICNIRP阈值的9.26%;E值最大为0.393 V/m,占ICNIRP阈值的0.45%;心脏部位B值最大为3.118μT,占ICNIRP阈值的85.01%;E值最大为0.278 V/m,占ICNIRP阈值的0.32%;人体头部脑组织中SAR值为3.009×10^(−7)W/kg,远低于ICNIRP制定的公众电磁暴露推荐值。提示心脏起搏器无线充电过程对使用者的健康无明显影响。

In order to accurately evaluate the safety of electromagnetic exposure generated by wireless charging of pacemakers,the modeling constructions and simulation calculations were performed by the finite element simulation software COMSOL.Firstly,the models of human brain tissue,a simple thorax and heart were constructed.The distributions of magnetic induction intensity(B),induced electric field intensity(E),as well as the distribution of SAR values in human head tissue generated in those three parts were obtained.In the calculations,the operating frequency of the wireless charging system was set to 251 kHz.Simulation results showed that maximum B value in human head model was 0.337μT,accounting for 9.26%of ICNIRP threshold,the maximum E value was 0.393 V/m,accounting for 0.45%of ICNIRP threshold.In human heart model,the maximum B value was 3.118μT,accounting for 85.01%of ICNIRP threshold,the maximum E value was 0.278 V/m,accounting for 0.32%of ICNIRP threshold.And in human brain tissue,SAR value was 3.009×10^(−7)W/kg,which was much lower than the recommended value of public electromagnetic exposure established by ICNIRP.This indicates that the wireless charging process of the pacemaker will not pose a health risk to users.