Virtanen Hanna, Keshvari Jafar, Lappalainen Reijo
Department of Applied Physics, University of Kuopio, Kuopio, Finland.
Bioelectromagnetics. 2006 Sep;27(6):431-9. doi: 10.1002/bem.20224.
During the last decade, use of radio frequency (RF) applications like mobile phones and other wireless devices, has increased remarkably. This has triggered numerous studies related to possible health risks due to the exposure of RF electromagnetic (EM) fields. One safety aspect is the coupling of EM fields with active and passive implants in the human body. While interactions with active implants have been quite extensively researched, only a few studies have focused on passive implants. The present article reviews interaction mechanisms and studies of passive metallic, that is, conductive, implants in common external RF EM fields. It is found that implants have been mostly studied numerically, and experimental studies are rare. Furthermore, the studies cover mostly far-field conditions and only a few have studied implants in near fields. A summary of results indicates that a conductive object in tissues may cause notable local enhancement of the EM field and thus enhanced power absorption. The degree of enhancement depends, for example, on the orientation, the dimensions, the shape, and the location of the implant. However, in most of the cases, the field enhancement has not been strong enough to cause remarkable excess heating (more than 1 degrees C) of tissues.
在过去十年中，手机和其他无线设备等射频（RF）应用的使用显著增加。这引发了众多关于射频电磁场（EM）暴露可能带来的健康风险的研究。一个安全方面是电磁场与人体中主动和被动植入物的耦合。虽然与主动植入物的相互作用已经得到了相当广泛的研究，但只有少数研究关注被动植入物。本文综述了常见外部射频电磁场中被动金属（即导电）植入物的相互作用机制和研究。研究发现，植入物大多是通过数值模拟进行研究的，实验研究很少。此外，这些研究大多涵盖远场条件，只有少数研究了近场中的植入物。结果总结表明，组织中的导电物体可能会导致电磁场的显著局部增强，从而增强功率吸收。增强程度例如取决于植入物的方向、尺寸、形状和位置。然而，在大多数情况下，场增强还不足以导致组织显著过热（超过1摄氏度）。
