Thermal Response of Human Skin to Microwave Energy: A Critical Review

2016 · Unclear · Low evidence

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UnclearLow evidencePaper 1430

Study snapshot

Publicationmanual · 2016

Study typereview

Reported directionUnclear

Evidence ratingLow

Abstract

Thermal Response of Human Skin to Microwave Energy: A Critical Review Foster KR, Ziskin MC, Balzano Q.Thermal Response of Human Skin to Microwave Energy: A Critical Review. Health Phys. 2016 Dec;111(6):528-541. Abstract This is a review/modeling study of heating of tissue by microwave energy in the frequency range from 3 GHz through the millimeter frequency range (30-300 GHz). The literature was reviewed to identify studies that reported RF-induced increases in skin temperature. A simple thermal model, based on a simplified form of Pennes' bioheat equation (BHTE), was developed, using parameter values taken from the literature with no further adjustment. The predictions of the model were in excellent agreement with available data. A parametric analysis of the model shows that there are two heating regimes with different dominant mechanisms of heat transfer. For small irradiated areas (less than about 0.5-1 cm in radius) the temperature increase at the skin surface is chiefly limited by conduction of heat into deeper tissue layers, while for larger irradiated areas, the steady-state temperature increase is limited by convective cooling by blood perfusion. The results support the use of this simple thermal model to aid in the development and evaluation of RF safety limits at frequencies above 3 GHz and for millimeter waves, particularly when the irradiated area of skin is small. However, very limited thermal response data are available, particularly for exposures lasting more than a few minutes to areas of skin larger than 1-2 cm in diameter. The paper concludes with comments about possible uses and limitations of thermal modeling for setting exposure limits in the considered frequency range. ncbi.nlm.nih.gov

Machine Enhanced Logic

AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typereview

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

Exposuremicrowave/mmWave

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Reviewed studies reporting RF-induced increases in skin temperature for exposures from 3 GHz through 30–300 GHz and developed a simple thermal model based on a simplified Pennes bioheat equation using literature parameter values. Model predictions were reported to be in excellent agreement with available data, and a parametric analysis suggested two heating regimes depending on irradiated area size (conduction-limited for small areas; perfusion-limited for larger areas). The authors note limited thermal response data, especially for exposures longer than a few minutes and for skin areas larger than 1–2 cm diameter, and suggest the model can aid development/evaluation of RF safety limits above 3 GHz and for millimeter waves.

Outcomes measured

RF-induced increases in skin temperature
thermal response/heating of skin tissue
model agreement with available thermal response data

Limitations

Very limited thermal response data available, particularly for exposures lasting more than a few minutes
Very limited thermal response data for irradiated skin areas larger than 1–2 cm in diameter

View raw extracted JSON

{
  "study_type": "review",
  "exposure": {
    "band": "microwave/mmWave",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "RF-induced increases in skin temperature",
    "thermal response/heating of skin tissue",
    "model agreement with available thermal response data"
  ],
  "main_findings": "Reviewed studies reporting RF-induced increases in skin temperature for exposures from 3 GHz through 30–300 GHz and developed a simple thermal model based on a simplified Pennes bioheat equation using literature parameter values. Model predictions were reported to be in excellent agreement with available data, and a parametric analysis suggested two heating regimes depending on irradiated area size (conduction-limited for small areas; perfusion-limited for larger areas). The authors note limited thermal response data, especially for exposures longer than a few minutes and for skin areas larger than 1–2 cm diameter, and suggest the model can aid development/evaluation of RF safety limits above 3 GHz and for millimeter waves.",
  "effect_direction": "unclear",
  "limitations": [
    "Very limited thermal response data available, particularly for exposures lasting more than a few minutes",
    "Very limited thermal response data for irradiated skin areas larger than 1–2 cm in diameter"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "skin temperature",
    "thermal modeling",
    "Pennes bioheat equation",
    "BHTE",
    "microwave",
    "millimeter wave",
    "RF safety limits",
    "3 GHz",
    "30–300 GHz",
    "irradiated area",
    "blood perfusion",
    "conduction"
  ],
  "suggested_hubs": [
    {
      "slug": "who-icnirp",
      "weight": 0.6,
      "reason": "Discusses use of thermal modeling to aid development/evaluation of RF safety limits above 3 GHz and for millimeter waves."
    },
    {
      "slug": "5g-policy",
      "weight": 0.45,
      "reason": "Covers frequencies above 3 GHz including millimeter waves relevant to higher-frequency wireless policy discussions."
    }
  ]
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: Not supplied
PubMed: Not supplied

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