Dielectric properties of body tissues.

Clinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics · 1987 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 6220

Study snapshot

PublicationClinical physics and physiological measurement : an official journal of the Hospital Physicists' Association, Deutsche Gesellschaft fur Medizinische Physik and the European Federation of Organisations for Medical Physics · 1987

Study typereview

Reported directionUnclear

Evidence ratingInsufficient

Abstract

A review is given of the dielectric properties of various mammalian tissues and biological fluids for the frequency range from 1 Hz to 10 GHz. The properties considered are the frequency variations of the relative permittivity and electrical conductivity. An attempt has been made to present data which can be considered to be the most typical for each material. The dielectric properties of aqueous solutions of amino-acids, polypeptides, proteins, and then cells, are first outlined in order to lay the groundwork for the understanding of the properties of tissues. The electrical characteristics of various tissues and blood are presented in tabular and graphical form, and the differences between normal and cancerous tissue is also discussed. The effects of necrosis and temperature changes are described and the important contribution that water makes to the overall properties is emphasised. An insight into some of the dominant physiological and biophysical processes responsible for the dielectric properties of biological materials is also attempted, since this should aid further developments of both the diagnostic and therapeutic applications of radiofrequency and microwave radiation. Such information is also relevant to an understanding of the possible biological hazards of such radiation. The ways in which dielectric studies can aid an understanding at the molecular level of the basic physiological differences between normal and cancerous tissue, as well as of the physico-chemical state of biological water, are also described.

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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 typereview

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureELF to microwave

Evidence strengthInsufficientConfidence: 74% · Peer reviewed: yes

Main findings

Reviews dielectric properties (relative permittivity and electrical conductivity) of mammalian tissues and biological fluids across 1 Hz to 10 GHz, presenting typical data for materials and discussing influences such as water content, necrosis, and temperature. Differences between normal and cancerous tissue dielectric characteristics are discussed, with relevance noted for diagnostic/therapeutic radiofrequency and microwave applications and for understanding potential hazards.

Outcomes measured

Dielectric properties (relative permittivity)
Dielectric properties (electrical conductivity)
Differences in dielectric properties between normal and cancerous tissue
Effects of necrosis on dielectric properties
Effects of temperature changes on dielectric properties
Role of water in dielectric properties

View raw extracted JSON

{
  "study_type": "review",
  "exposure": {
    "band": "ELF to microwave",
    "source": null,
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Dielectric properties (relative permittivity)",
    "Dielectric properties (electrical conductivity)",
    "Differences in dielectric properties between normal and cancerous tissue",
    "Effects of necrosis on dielectric properties",
    "Effects of temperature changes on dielectric properties",
    "Role of water in dielectric properties"
  ],
  "main_findings": "Reviews dielectric properties (relative permittivity and electrical conductivity) of mammalian tissues and biological fluids across 1 Hz to 10 GHz, presenting typical data for materials and discussing influences such as water content, necrosis, and temperature. Differences between normal and cancerous tissue dielectric characteristics are discussed, with relevance noted for diagnostic/therapeutic radiofrequency and microwave applications and for understanding potential hazards.",
  "effect_direction": "unclear",
  "limitations": [],
  "evidence_strength": "insufficient",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "dielectric properties",
    "relative permittivity",
    "electrical conductivity",
    "mammalian tissues",
    "biological fluids",
    "frequency dependence",
    "1 Hz to 10 GHz",
    "radiofrequency",
    "microwave",
    "normal vs cancerous tissue",
    "necrosis",
    "temperature",
    "water content"
  ],
  "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: 10.1088/0143-0815/8/4a/002
PubMed: 3568571

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