Whole-body and local dosimetry in rats exposed to 2.45-GHz microwave radiation.

Abstract

Rat cadavers oriented parallel to the electric field were exposed to 2.45-GHz microwave radiation. The weights of the cadavers ranged from approx. 5 to 320 g and their lengths ranged from approx. 5 to 21.5 cm. Whole-body specific absorption rates (SAR) were measured using calorimetric techniques, and local specific absorption rates were obtained from time-temperature profiles measured with a non-interacting thermistor probe (Vitek). The whole-body SARs decreased by a factor of 12 in rat pups weighing 5 g as compared to adult rats weighing 320 g. The local SARs in the colon were slightly higher than the whole-body SARs for animals in the weight range from 40 to 320 g and approx. 2.5 times higher in animals ranging from 10 to 30 g. The local SARs in the brain were two to three times higher than the whole-body SARs for animals ranging in weights from 20 to 320 g. The data show that it is important to measure both whole-body SARs and local SARs when conducting experiments to determine biological effects in order to adequately explain any biological changes and to extrapolate data from different sizes and species of animals.

AI evidence extraction

Main findings

Whole-body SAR decreased with increasing body weight/size, with a reported 12-fold lower whole-body SAR in 5 g pups compared with 320 g adults. Local SARs exceeded whole-body SARs: colon local SAR was slightly higher for 40–320 g animals and ~2.5× higher for 10–30 g animals; brain local SAR was ~2–3× higher than whole-body SAR for 20–320 g animals.

Outcomes measured

• Whole-body specific absorption rate (SAR)
• Local SAR in colon
• Local SAR in brain

Limitations

• Cadaver (non-living) model; does not assess biological/health outcomes
• Sample size not reported in abstract
• Exposure conditions beyond orientation (e.g., field strength/power density, duration) not reported in abstract

{
    "study_type": "exposure_assessment",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2450,
        "sar_wkg": null,
        "duration": null
    },
    "population": "Rat cadavers (various sizes/weights)",
    "sample_size": null,
    "outcomes": [
        "Whole-body specific absorption rate (SAR)",
        "Local SAR in colon",
        "Local SAR in brain"
    ],
    "main_findings": "Whole-body SAR decreased with increasing body weight/size, with a reported 12-fold lower whole-body SAR in 5 g pups compared with 320 g adults. Local SARs exceeded whole-body SARs: colon local SAR was slightly higher for 40–320 g animals and ~2.5× higher for 10–30 g animals; brain local SAR was ~2–3× higher than whole-body SAR for 20–320 g animals.",
    "effect_direction": "unclear",
    "limitations": [
        "Cadaver (non-living) model; does not assess biological/health outcomes",
        "Sample size not reported in abstract",
        "Exposure conditions beyond orientation (e.g., field strength/power density, duration) not reported in abstract"
    ],
    "evidence_strength": "insufficient",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "2.45 GHz",
        "microwave radiation",
        "dosimetry",
        "specific absorption rate",
        "SAR",
        "calorimetry",
        "thermistor probe",
        "rat cadavers",
        "whole-body SAR",
        "local SAR",
        "brain",
        "colon"
    ],
    "suggested_hubs": []
}

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