研究のタイプ: 医学／生物学の研究 (experimental study)

[マイクロ波ばく露に対するラットの脳電気活動（EEG）および脳循環（REG）の同時応答] med./bio.

Simultaneous response of brain electrical activity (EEG) and cerebral circulation (REG) to microwave exposure in rats

著者: Thuroczy G, Kubinyi G, Bodo M, Bakos J, Szabo LD
掲載誌: Rev Environ Health 1994; 10 (2): 135-148
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この研究は、低レベルの変調波または連続波の電磁界が、CNSにおける全身的または局所的な調節メカニズムに測定可能な影響を引き起こすか、また、電磁界により刺激されたそれらの調節メカニズム（全身または局所または両方）とCNS活動の間に何らかの相関はあるかについて調べた。麻酔したラット（n=40）を用いて、2つのばく露条件：1) 2.45 GHz CWマイクロ波への10分間の全身ばく露の前後に、2) 16Hz振幅変調の4GHzマイクロ波への30分間の局所ばく露中に、CNSへの影響を心臓血管系への影響と同時観察した。脳電図（EEG）、脳血流図（REG）、脳組織のDCインピーダンスおよび温度、心電図（ECG）のを同時記録した。その結果、30mW / cm2、2.45GHz CWへの10分間の全身ばく露後、EEGスペクトルのトータルパワーが増加した；10mW / cm 2の場合には変化がなかった；しかし、10mW / cm 2において、脳血流は増加した；4GHz局所ばく露（SARは42mW / g）で生じる脳の温度上昇は、EEGのデルタはパワーの増加と同時に脳血流の増加を示した、など多くの複雑な知見を報告している。

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研究目的（著者による）

The study was related to the following questions: 1) Does a weak modulated or continuous wave (CW) electromagnetic field cause measurable effects on systemic and/or localized regulation mechanism in the CNS? 2) Is there any correlation between the field activated systemic and/or localized regulatory mechanisms and the changes in CNS activity? 3) Does evaluation of measured biopotentials provide more information about the effects on the CNS of modulated and continuous wave (CW) electromagnetic field irradiation? In two different experiments on rats 1) before and after 10 min, whole body exposures to 2.45 GHz CW microwaves, and 2) during 30 min exposures to 4 GHz amplitude modulated microwaves (partial body exposure), the effects on the CNS were observed simultaneously with those on the cardiovascular system.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 2.45 GHz
Modulation type: CW
ばく露時間: continuous for 10 min
whole body exposure
  • 電力密度: 10 mW/cm² unspecified (at the head)
  • SAR: 2.3 mW/g average over mass (whole body)
  • SAR: 8.3 mW/g average over mass (brain) (± 1.7 mW/g)
  • SA: 1.23 Ws/g average over mass (whole body)
  • SA: 4.98 Ws/g average over mass (brain) (± 1.02 Ws/g)
  • 電力密度: 30 mW/cm² unspecified (at the head)
  • SAR: 6.9 mW/g average over mass (whole body)
  • SAR: 25.1 mW/g average over mass (brain) (± 5.2 mW/g)
  • SA: 4.14 Ws/g average over mass (whole body)
  • SA: 14.94 Ws/g average over mass (brain) (± 3.05 Ws/g)
ばく露2: 4 GHz
Modulation type: CW
ばく露時間: continuous for 30 min
brain localized exposure
  • 電力: 300 mW
  • 電力密度: 8.44 mW/cm² unspecified
  • SAR: 8.44 mW/g average over mass (brain) (± 2.7 mW/g)
  • SA: 15.12 Ws/g average over mass (brain) (± 4.9 Ws/g)
  • 電力: 600 mW
  • 電力密度: 16.88 mW/cm² unspecified
  • SAR: 16.8 mW/g average over mass (brain) (± 5.4 mW/g)
  • SA: 30.24 Ws/g average over mass (brain) (± 9.8 Ws/g)
  • 電力: 1,500 mW
  • 電力密度: 42.4 mW/cm² unspecified
  • SAR: 42 mW/g average over mass (brain) (± 13.5 mW/g)
  • SA: 75.6 Ws/g average over mass (brain) (± 24.5 Ws/g)
ばく露3: 4 GHz
Modulation type: AM
ばく露時間: continuous for 30 min
brain localized exposure
  • 電力: 300 mW
  • 電力密度: 8.44 mW/cm² unspecified
  • SAR: 8.44 mW/g average over mass (brain) (± 2.7 mW/g)
  • SA: 15.12 Ws/g average over mass (brain) (± 4.9 Ws/g)
  • 電力: 600 mW
  • 電力密度: 16.88 mW/cm² unspecified
  • SAR: 16.8 mW/g average over mass (brain) (± 5.4 mW/g)
  • SA: 30.24 Ws/g average over mass (brain) (± 9.8 Ws/g)

ばく露1

主たる特性
周波数 2.45 GHz
タイプ
  • electromagnetic field
特性
  • near field
ばく露時間 continuous for 10 min
Additional information whole body exposure
Modulation
Modulation type CW
ばく露装置
ばく露の発生源／構造
チャンバの詳細 anechoic room of 2.55 m x 1.8 m x 2.9 m
パラメータ
測定量 値 種別 Method Mass 備考
電力密度 10 mW/cm² unspecified 測定値 - at the head
SAR 2.3 mW/g average over mass 推定値 whole body -
SAR 8.3 mW/g average over mass 測定値および計算値 brain ± 1.7 mW/g
SA 1.23 Ws/g average over mass 推定値 whole body -
SA 4.98 Ws/g average over mass 測定値および計算値 brain ± 1.02 Ws/g
電力密度 30 mW/cm² unspecified 測定値 - at the head
SAR 6.9 mW/g average over mass 推定値 whole body -
SAR 25.1 mW/g average over mass 測定値 brain ± 5.2 mW/g
SA 4.14 Ws/g average over mass 推定値 whole body -
SA 14.94 Ws/g average over mass 測定値 brain ± 3.05 Ws/g
測定および計算の詳細

The incident power to the horn antenna (G = 14 dB) was measured continuously using a directional coupler and a power meter. The spatial pattern of power density was measured using a radiation monitor. The SAR in the brain cortex was measured at 30 mW/cm² (30 s) using a thermocouple placed perpendicularly to the E-field and inserted 5 mm deep into the brain tissue of anaesthetized animals. From these data the SAR values at 10 mW/cm² were calculated.

ばく露2

主たる特性
周波数 4 GHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 30 min
Additional information brain localized exposure
Modulation
Modulation type CW
ばく露装置
ばく露の発生源／構造
ばく露装置の詳細 The irradiation was performed in a waveguide setup TE-cell. A standard WR waveguide was extended up to 100 x 60 mm and connected through a horn to the waveguide.
パラメータ
測定量 値 種別 Method Mass 備考
電力 300 mW - 測定値 - -
電力密度 8.44 mW/cm² unspecified 測定値 - -
SAR 8.44 mW/g average over mass 測定値および計算値 brain ± 2.7 mW/g
SA 15.12 Ws/g average over mass 測定値および計算値 brain ± 4.9 Ws/g
電力 600 mW - 測定値 - -
電力密度 16.88 mW/cm² unspecified 測定値 - -
SAR 16.8 mW/g average over mass 測定値および計算値 brain ± 5.4 mW/g
SA 30.24 Ws/g average over mass 測定値および計算値 brain ± 9.8 Ws/g
電力 1,500 mW - 測定値 - -
電力密度 42.4 mW/cm² unspecified 測定値 - -
SAR 42 mW/g average over mass 測定値および計算値 brain ± 13.5 mW/g
SA 75.6 Ws/g average over mass 測定値および計算値 brain ± 24.5 Ws/g
測定および計算の詳細

The incident, reflected and transmitted powers were measured using directional couplers and power meters. Power density in the cross section of the TE-cell was measured through a slot using a small (3 mm) loop antenna at 1 cm depth from the top wall. The spatial pattern of SAR distribution in the brain cortex was measured at 2 W (56 mW/g SAR) CW (15 s) using a thermocouple placed perpendicularly to the E-field and inserted 5 mm deep into the brain tissue of anaesthetized animals with their heads placed toward the generator. The average SAR values versus the incident powers were calculated from these data.

ばく露3

主たる特性
周波数 4 GHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 30 min
Additional information brain localized exposure
Modulation
Modulation type AM
Modulation frequency 16 Hz
Modulation depth 70 %
Additional information

sine wave
ばく露装置
ばく露の発生源／構造
  • same setup as in E2
パラメータ
測定量 値 種別 Method Mass 備考
電力 300 mW - 測定値 - -
電力密度 8.44 mW/cm² unspecified 測定値 - -
SAR 8.44 mW/g average over mass 測定値および計算値 brain ± 2.7 mW/g
SA 15.12 Ws/g average over mass 測定値および計算値 brain ± 4.9 Ws/g
電力 600 mW - 測定値 - -
電力密度 16.88 mW/cm² unspecified 測定値 - -
SAR 16.8 mW/g average over mass 測定値および計算値 brain ± 5.4 mW/g
SA 30.24 Ws/g average over mass 測定値および計算値 brain ± 9.8 Ws/g

ばく露を受けた生物:

方法 影響評価項目／測定パラメータ／方法

研究対象とした生物試料:
研究対象とした臓器系:
調査の時期:
  • ばく露中
  • ばく露後

研究の主なアウトカム（著者による）

The total power of EEG spectra increased after whole body 2.45 GHz continuous wave (CW) exposure (30 mW/cm²) for 10 min. No changes occured at 10 mW/cm². The cerebral blood flow increased after 10 mW/cm² irradiation. The power of EEG delta (0.5-4 Hz) waves was increased by thermal level of brain localized 4 GHz continuous wave (CW) irradiation (at 42 mW/g SAR) simultaneously with the rheoencephalogram amplitude as an index of cerebral blood flow. Amplitude modulation at 16 Hz (8.4 mW/g SAR) was associated with increased power of EEG beta (14.5-30 Hz) waves but changes in the cerebral blood flow were not observed. CW exposure at 8.4 mW/g increased the cerebral blood flow, but did not change EEG spectra.

研究の種別:

研究助成

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