title: Significant RF-EMF and thermal levels observed in a computational model of a person with a tibial plate for grounded 40 MHz exposure.
abstract: Using numerical modeling, a worst-case scenario is considered when a person with a metallic implant is exposed to a radiofrequency (RF) electromagnetic field (EMF). An adult male standing on a conductive ground plane was exposed to a 40 MHz vertically polarized plane wave field, close to whole-body resonance where maximal induced current flows are expected in the legs. A metal plate (50-300 mm long) was attached to the tibia in the left leg. The findings from this study re-emphasize the need to ensure compliance with limb current reference levels for exposures near whole-body resonance, and not just rely on compliance with ambient electric (E) and magnetic (H) field reference levels. Moreover, we emphasize this recommendation for someone with a tibial plate, as failure to comply may result in significant tissue damage (increases in the localized temperature of 5-10 °C were suggested by the modeling for an incident E-field of 61.4 V/m root mean square (rms)). It was determined that the occupational reference level for limb current (100 mA rms), as stipulated in the 1998 guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), is satisfied if the plane wave incident E-field levels are no more than 29.8 V/m rms without an implant and 23.4 V/m rms for the model with a 300 mm implant.
authors.affiliation: Swinburne University of Technology, Faculty of Health, Arts and Design, Hawthorn, Victoria, Australia.
authors.forename: Robert L
authors.initials: RL
authors.lastname: McIntosh
authors.forename: Steve
authors.initials: S
authors.lastname: Iskra
authors.forename: Vitas
authors.initials: V
authors.lastname: Anderson
mesh_terms: D000328:Adult; D001860:Bone Plates / Q000009:adverse effects*; D003198:Computer Simulation; D004574:Electromagnetic Fields / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008954:Models, Biological; D019736:Prostheses and Implants / Q000009:adverse effects*; D011846:Radio Waves / Q000009:adverse effects*; D013696:Temperature; D013977:Tibia
keywords: RF worker; limb currents; metallic implants; radiofrequency safety standards