Dosimetric Electromagnetic Safety of People With Implants: A Neglected Population?

Abstract

Category: Bioelectromagnetics, Dosimetry, Implant Safety Tags: electromagnetic fields, implants, safety guidelines, psSAR10mg, wireless power transfer, regulatory gap, exposure risk DOI: 10.1002/bem.70023 URL: pmc.ncbi.nlm.nih.gov Overview Electromagnetic (EM) safety guidelines are intended to protect both the public and workers from the potential risks associated with exposure to all types of EM sources, excluding medical EM sources. However, it has never been systematically examined whether individuals with conductive implants are afforded protection by these guidelines. The presence of an implant could potentially create local field enhancements that increase risk under realistic exposure scenarios. Findings - This study systematically assessed the extent to which current EM safety initiatives safeguard people with conductive implants, focusing specifically on the risk from local field enhancements. - Generic bare and insulated implants of various lengths were tested across tissue properties and frequency ranges from 10 kHz to 1 GHz. Local enhancement of psSAR10mg and locally averaged electric fields were observed, with increases of up to 10 dB at 1 GHz and over 100 dB at frequencies below 100 MHz. - Human anatomical models (ViP Ella v3.0) with implanted devices were exposed to realistic sources including an 85 kHz wireless power transfer coil and a 450 MHz dipole source. Results showed that safety limits were exceeded by a factor over 10 (greater than 20 dB or above 115 V/m at 85 kHz), and psSAR10mg reached 7.9 W/kg at 450 MHz, leading to a temperature rise of less than 0.4 K after six minutes. Conclusion - The assumption that induced fields inside the human body are not sufficiently uniform to cause unacceptable risk was disproved, particularly at frequencies below 450 MHz. - Current safety and product guidelines inadequately protect patients with implants. - The paper provides proposals for needed regulatory adjustments to close this safety gap for people with implants. Important Note: There is a clear connection between electromagnetic field exposure and increased health risk for people with conductive implants. The presence of implants can cause significant local field enhancements, which exceed safety guidelines and may contribute to unacceptable risks.

AI evidence extraction

Main findings

Generic conductive implants produced local enhancements in psSAR10mg and locally averaged electric fields across 10 kHz to 1 GHz, with increases up to 10 dB at 1 GHz and over 100 dB below 100 MHz. In anatomical models with implants exposed to an 85 kHz wireless power transfer coil and a 450 MHz dipole source, reported safety limits were exceeded by a factor >10 (e.g., >115 V/m at 85 kHz), and psSAR10mg reached 7.9 W/kg at 450 MHz with a temperature rise <0.4 K after six minutes. The authors conclude current safety/product guidelines inadequately protect people with implants and propose regulatory adjustments.

Outcomes measured

• psSAR10mg (peak spatial SAR averaged over 10 mg)
• locally averaged electric fields (V/m)
• exceedance of safety limits
• temperature rise (K)

Suggested hubs

• who-icnirp (0.62)
  Assesses adequacy of current EM safety guidelines/limits for a specific population (people with implants) and proposes regulatory adjustments.

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    "exposure": {
        "band": "ELF/RF",
        "source": "wireless power transfer; dipole source",
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": "six minutes (temperature rise assessment at 450 MHz)"
    },
    "population": "Human anatomical models (ViP Ella v3.0) with implanted devices; generic bare and insulated implants in tissue models",
    "sample_size": null,
    "outcomes": [
        "psSAR10mg (peak spatial SAR averaged over 10 mg)",
        "locally averaged electric fields (V/m)",
        "exceedance of safety limits",
        "temperature rise (K)"
    ],
    "main_findings": "Generic conductive implants produced local enhancements in psSAR10mg and locally averaged electric fields across 10 kHz to 1 GHz, with increases up to 10 dB at 1 GHz and over 100 dB below 100 MHz. In anatomical models with implants exposed to an 85 kHz wireless power transfer coil and a 450 MHz dipole source, reported safety limits were exceeded by a factor >10 (e.g., >115 V/m at 85 kHz), and psSAR10mg reached 7.9 W/kg at 450 MHz with a temperature rise <0.4 K after six minutes. The authors conclude current safety/product guidelines inadequately protect people with implants and propose regulatory adjustments.",
    "effect_direction": "harm",
    "limitations": [],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "dosimetry",
        "implant safety",
        "conductive implants",
        "local field enhancement",
        "psSAR10mg",
        "electric field",
        "wireless power transfer",
        "85 kHz",
        "450 MHz",
        "10 kHz to 1 GHz",
        "safety guidelines",
        "regulatory gap"
    ],
    "suggested_hubs": [
        {
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            "weight": 0.61999999999999999555910790149937383830547332763671875,
            "reason": "Assesses adequacy of current EM safety guidelines/limits for a specific population (people with implants) and proposes regulatory adjustments."
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}

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