Evaluation of specific absorption rate as a dosimetric quantity for electromagnetic fields bioeffects.

PloS one · 2013 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 4606

Study snapshot

PublicationPloS one · 2013

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

PURPOSE: To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. METHODS: We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. RESULTS: WE FIND THAT: a) The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b) All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c) The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. CONCLUSIONS: SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc) which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar uncertainty to predict the biological effect due to non-linearity.

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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 typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

The authors argue that energy absorbed during environmentally accounted EMF exposures is typically below thermal levels, and that existing SAR estimation methods (especially those relying on tissue conductivity and internal electric field) have serious deficiencies. They state that estimating SAR accurately would require measuring temperature increases in tissue, which are usually negligible at environmental intensities and therefore not measurable.

Outcomes measured

Validity/appropriateness of SAR as a dosimetric quantity for EMF bioeffects
Precision/limitations of SAR estimation methods
Thermal vs non-thermal characterization of EMF bioeffects (conceptual)

Limitations

Appears to be a conceptual/physics-based evaluation rather than an empirical study of health outcomes (no specific experimental dataset described in the abstract).
No specific EMF source, frequency, exposure duration, or population is specified in the abstract.

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Validity/appropriateness of SAR as a dosimetric quantity for EMF bioeffects",
    "Precision/limitations of SAR estimation methods",
    "Thermal vs non-thermal characterization of EMF bioeffects (conceptual)"
  ],
  "main_findings": "The authors argue that energy absorbed during environmentally accounted EMF exposures is typically below thermal levels, and that existing SAR estimation methods (especially those relying on tissue conductivity and internal electric field) have serious deficiencies. They state that estimating SAR accurately would require measuring temperature increases in tissue, which are usually negligible at environmental intensities and therefore not measurable.",
  "effect_direction": "unclear",
  "limitations": [
    "Appears to be a conceptual/physics-based evaluation rather than an empirical study of health outcomes (no specific experimental dataset described in the abstract).",
    "No specific EMF source, frequency, exposure duration, or population is specified in the abstract."
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "specific absorption rate",
    "SAR",
    "dosimetry",
    "electromagnetic fields",
    "non-thermal effects",
    "thermal effects",
    "exposure assessment",
    "modulation",
    "frequency"
  ],
  "suggested_hubs": []
}

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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: 10.1371/journal.pone.0062663
PubMed: 23750202

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