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Repeated exposure to nanosecond high power pulsed microwaves increases cancer incidence in rat

2020 · Harm · Low evidence

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HarmLow evidencePaper 1506

Rats exposed to intense nanosecond high-power pulsed microwaves (carrier frequencies 10 and 3.7 GHz) showed few behavioural effects. After acute exposure, an avoidance reflex occurred at a very high thermal level (22 W/kg) and GFAP increased days after exposu…

Study snapshot

Publicationmanual · 2020
Study typeanimal
Reported directionHarm
Evidence ratingLow

Abstract

Repeated exposure to nanosecond high power pulsed microwaves increases cancer incidence in rat René de Seze, Carole Poutriquet, Christelle Gamez, Emmanuelle Maillot-Maréchal, Franck Robidel, Anthony Lecomte, Caroline Fonta. Repeated exposure to nanosecond high power pulsed microwaves increases cancer incidence in rat. PLOS One. 2020; 15(4): e0226858. doi: 10.1371/journal.pone.0226858 Abstract High-power microwaves are used to inhibit electronics of threatening military or civilian vehicles. This work aims to assess health hazards of high-power microwaves and helps to define hazard threshold levels of modulated radiofrequency exposures such as those emitted by the first generations of mobile phones. Rats were exposed to the highest possible field levels, under single acute or repetitive exposures for eight weeks. Intense microwave electric fields at 1 MV m-1 of nanoseconds duration were applied from two sources at different carrier frequencies of 10 and 3.7 GHz. The repetition rate was 100 pps, and the duration of train pulses lasted from 10 s to twice 8 min. The effects on the central nervous system were evaluated, by labelling brain inflammation marker GFAP and by performing different behavioural tests: rotarod, T-maze, beam-walking, open-field, and avoidance test. Long-time survival was measured in animals repeatedly exposed, and anatomopathological analysis was performed on animals sacrificed at two years of life or earlier in case of precocious death. Control groups were sham exposed. Few effects were observed on behaviour. With acute exposure, an avoidance reflex was shown at very high thermal level (22 W kg-1); GFAP was increased some days after exposure. Most importantly, with repeated exposures, survival time was 4-months shorter in the exposed group, with eleven animals exhibiting a large sub-cutaneous tumour, compared to two in the sham group. A residual X-ray exposure was also present in the beam (0.8 Gy), which is probably not a bias for the observed result. High power microwaves below thermal level in average, can increase cancer prevalence and decrease survival time in rats, without clear effects on behaviour. The parameters of this effect need to be further explored, and a more precise dosimetry to be performed. Open access paper: journals.plos.org

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 typeanimal
Effect directionharm
PopulationRats
Sample sizeNot supplied
Exposuremicrowave · 22 W/kg · single acute or repetitive exposures for eight weeks; pulse trains 10 s to twice 8 min; repetition rate 100 pps; nanosecond pulses
Evidence strengthLowConfidence: 74% · Peer reviewed: yes

Main findings

Rats exposed to intense nanosecond high-power pulsed microwaves (carrier frequencies 10 and 3.7 GHz) showed few behavioural effects. After acute exposure, an avoidance reflex occurred at a very high thermal level (22 W/kg) and GFAP increased days after exposure. With repeated exposures over eight weeks, survival time was reported as 4 months shorter in exposed animals, and 11 animals exhibited a large sub-cutaneous tumour versus 2 in sham-exposed controls.

Outcomes measured

  • Cancer incidence/prevalence (sub-cutaneous tumours)
  • Survival time
  • Behavioural performance (rotarod, T-maze, beam-walking, open-field, avoidance test)
  • Brain inflammation marker GFAP

Limitations

  • Sample size not stated in the abstract
  • Residual X-ray exposure in the beam (0.8 Gy) was present (authors state it is probably not a bias)
  • Authors note need for more precise dosimetry and further exploration of parameters
View raw extracted JSON
{
  "study_type": "animal",
  "exposure": {
    "band": "microwave",
    "source": "high-power pulsed microwaves",
    "frequency_mhz": null,
    "sar_wkg": 22,
    "duration": "single acute or repetitive exposures for eight weeks; pulse trains 10 s to twice 8 min; repetition rate 100 pps; nanosecond pulses"
  },
  "population": "Rats",
  "sample_size": null,
  "outcomes": [
    "Cancer incidence/prevalence (sub-cutaneous tumours)",
    "Survival time",
    "Behavioural performance (rotarod, T-maze, beam-walking, open-field, avoidance test)",
    "Brain inflammation marker GFAP"
  ],
  "main_findings": "Rats exposed to intense nanosecond high-power pulsed microwaves (carrier frequencies 10 and 3.7 GHz) showed few behavioural effects. After acute exposure, an avoidance reflex occurred at a very high thermal level (22 W/kg) and GFAP increased days after exposure. With repeated exposures over eight weeks, survival time was reported as 4 months shorter in exposed animals, and 11 animals exhibited a large sub-cutaneous tumour versus 2 in sham-exposed controls.",
  "effect_direction": "harm",
  "limitations": [
    "Sample size not stated in the abstract",
    "Residual X-ray exposure in the beam (0.8 Gy) was present (authors state it is probably not a bias)",
    "Authors note need for more precise dosimetry and further exploration of parameters"
  ],
  "evidence_strength": "low",
  "confidence": 0.74,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "high-power microwaves",
    "pulsed microwaves",
    "nanosecond pulses",
    "10 GHz",
    "3.7 GHz",
    "rats",
    "cancer incidence",
    "tumour",
    "survival",
    "GFAP",
    "behavioural tests",
    "SAR",
    "dosimetry"
  ],
  "suggested_hubs": [
    {
      "slug": "military-high-power-microwaves",
      "weight": 0.86,
      "reason": "Study explicitly concerns high-power microwaves used to inhibit electronics of military/civilian vehicles and assesses health hazards."
    }
  ]
}
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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.0226858
PubMed: Not supplied

Read the original paper →

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