Temperature distribution and Specific Absorption Rate inside a child's head

2017 · Mixed · Low evidence

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MixedLow evidencePaper 1390

Study snapshot

Publicationmanual · 2017

Study typeengineering

Reported directionMixed

Evidence ratingLow

Abstract

Temperature distribution and Specific Absorption Rate inside a child's head Vladimir Stanković, Dejan Jovanović, Dejan Krstić, Vera Marković, Nenad Cvetković. Temperature distribution and Specific Absorption Rate inside a child's head. International Journal of Heat and Mass Transfer, Volume 104, January 2017, Pages 559-565. Highlights • The numerical analysis of SAR and temperature distribution within a child head. • Determination of SAR and increasing of temperature within biological tissues. • Dependence of the SAR and temperature values on the distance. • Comparison of results obtained by numerical calculation with experimental results. Abstract This paper represents the numerical analysis of Specific Absorption Rate (SAR) and temperature distribution within a real child head model exposed to mobile phone radiation at the frequency of f = 900 MHz. In this research the SAR and temperature distribution are obtained by numerical solutions of the equation of electromagnetic waves propagation and by bioheat equation, respectively, and are shown inside different biological tissues and organs during exposure to electromagnetic radiation from a mobile phone. As electromagnetic properties of tissues depend on the electromagnetic waves frequency, the value of SAR and temperature will be different for different tissues and organs. The maximum absorption of electromagnetic energy is in the surface layers of the model, whereby this value is greater than the maximum allowed value defined by standards. Furthermore, the increase in temperature is the highest in those biological tissues and organs that are closest to the source of radiation i.e. a mobile phone. Moving away from a mobile phone, the temperature decreases, but more slowly than the SAR values. In the analysis of the temperature rise resulting from tissues and organs heating due to the effects of electromagnetic fields on a child's head, special attention will be given to the maximum temperature increase in the brain. Conclusion This study investigated the distribution of SAR and temperature rise in the anatomical model of a child's head exposed to electromagnetic fields from mobile phones. It was determined that although the values of SAR and temperature decrease with the distance from the source of radiation, it is not possible to establish a direct connection between these quantities. This is primarily because the SAR represents instantaneous heating of tissue. The distribution of temperature will vary compared to the distribution of SAR due to different mechanisms of heat transfer in the thermal model of a child's head. Although the value of SAR in the brain is below the maximum allowable values, the fact that the SAR levels in certain tissues and organs of the model are significantly above the maximum allowable value must not be disregarded. It is precisely these areas of a child's head that should be the focus of further research of possible unwanted effects of mobile phone radiation. On the other hand, the temperature of the brain does not exceed 0.7 C, which is below the threshold for causing undesirable thermal effects on neurons [29], while in other parts of the head the temperature does not exceed 1 C. Of course, it should be noted that the exposure to electromagnetic radiation for 15 min was simulated. Therefore, the obtained results suggest that, in addition to a dosimetry analysis, it is also necessary to perform the thermal analysis of the impact of mobile phone radiation. bit.ly

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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 typeengineering

Effect directionmixed

PopulationChild head anatomical model

Sample sizeNot supplied

ExposureRF · 900 MHz · 15 min (simulated)

Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Numerical modeling of a child head exposed to 900 MHz mobile phone radiation found maximum electromagnetic energy absorption in surface layers, with SAR in some tissues/organs reported as above maximum allowable values defined by standards, while SAR in the brain was below allowable values. Simulated temperature rise was highest in tissues closest to the phone; brain temperature increase did not exceed 0.7°C and other head regions did not exceed 1°C during a simulated 15-minute exposure. SAR and temperature both decreased with distance, but the study reports no direct connection between them due to heat-transfer mechanisms affecting temperature distribution.

Outcomes measured

Specific Absorption Rate (SAR) distribution in tissues/organs
Temperature distribution/temperature rise in tissues/organs (including brain)
Distance dependence of SAR and temperature
Comparison of numerical vs experimental results (mentioned)

Limitations

Numerical/simulation study using an anatomical model rather than human participants
Exposure duration simulated for 15 minutes only
Specific SAR values and temperature values by tissue are not provided in the abstract
Standards/thresholds referenced but not specified in the abstract
Experimental comparison is mentioned but details are not provided in the abstract

View raw extracted JSON

{
  "study_type": "engineering",
  "exposure": {
    "band": "RF",
    "source": "mobile phone",
    "frequency_mhz": 900,
    "sar_wkg": null,
    "duration": "15 min (simulated)"
  },
  "population": "Child head anatomical model",
  "sample_size": null,
  "outcomes": [
    "Specific Absorption Rate (SAR) distribution in tissues/organs",
    "Temperature distribution/temperature rise in tissues/organs (including brain)",
    "Distance dependence of SAR and temperature",
    "Comparison of numerical vs experimental results (mentioned)"
  ],
  "main_findings": "Numerical modeling of a child head exposed to 900 MHz mobile phone radiation found maximum electromagnetic energy absorption in surface layers, with SAR in some tissues/organs reported as above maximum allowable values defined by standards, while SAR in the brain was below allowable values. Simulated temperature rise was highest in tissues closest to the phone; brain temperature increase did not exceed 0.7°C and other head regions did not exceed 1°C during a simulated 15-minute exposure. SAR and temperature both decreased with distance, but the study reports no direct connection between them due to heat-transfer mechanisms affecting temperature distribution.",
  "effect_direction": "mixed",
  "limitations": [
    "Numerical/simulation study using an anatomical model rather than human participants",
    "Exposure duration simulated for 15 minutes only",
    "Specific SAR values and temperature values by tissue are not provided in the abstract",
    "Standards/thresholds referenced but not specified in the abstract",
    "Experimental comparison is mentioned but details are not provided in the abstract"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "specific absorption rate",
    "SAR",
    "temperature rise",
    "bioheat equation",
    "child head model",
    "mobile phone radiation",
    "900 MHz",
    "dosimetry",
    "thermal analysis"
  ],
  "suggested_hubs": [
    {
      "slug": "mobile-phones",
      "weight": 0.9,
      "reason": "Study models SAR and temperature rise in a child head exposed to mobile phone radiation at 900 MHz."
    }
  ]
}

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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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