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

[GSM、DCS無線通信信号：ウイスター系ラットにおける慢性毒性および発がん性の同時研究] med./bio.

GSM and DCS Wireless Communication Signals: Combined Chronic Toxicity/Carcinogenicity Study in the Wistar Rat

著者: Smith P, Kuster N, Ebert S, Chevalier HJ
掲載誌: Radiat Res 2007; 168 (4): 480-492
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1グループにつき雄65匹、雌65匹のウイスター系ラットから成る合計1170匹のラットは、0.44、1.33、4.0W/kgの3種類の標準SARで、GSMまたはDCSの無線通信信号に、最高104週間(2時間/日、5日/週)ばく露した。予備研究で、最高ばく露レベルはラットの中核体温に測定可能な温度上昇を引き起こすことのできるレベルを下回ることが確認された。それぞれの変調信号について擬似ばく露群が追加された他、無拘束、無ばく露の(ケージ)対照群も作られた。1グループ当たり雄雌15匹ずつはばく露52週後に殺され、残った雄雌各50匹の中で生き残ったラットはばく露104週後に殺された。実験継続中の評価項目は、死亡率、臨床的症状、触知可能な腫瘤の記録、体重、飼料消費、検眼鏡検査、臨床病理的調査である。終末調査では、器官重量測定、巨視的および微視的な病理学検査が含まれた。無線通信信号に対する悪い反応は見られなかった。特に、原発腫瘍の発生率、複数の原発腫瘍があったラットの数、腫瘍の多様性と潜伏期間、腫瘍の転移があったラットの数、良性および悪性腫瘍の数において、無線通信信号ばく露ラットと擬似ばく露ラットの間には大きな違いはなかった。

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研究目的(acc. to editor)

To study the effects of GSM and DCS wireless communication signals on carcinogenicity in rats.

詳細情報

A total of 1200 rats were used. Groups of 65 male and 65 female rats were exposed to GSM and DCS signals at three different SAR values (4 W/kg, 1.33 W/kg, 0.44 W/kg). In addition, there was a sham exposed group for each signal type. An additional group of 65 males and 65 females was kept unexposed and unrestrained and served as the cage control.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 902 MHz
Modulation type: pulsed
ばく露時間: repeated daily exposure, 2 h/day, 5 days/week, for 52 or 104 weeks
  • SAR: 3.7 W/kg average over time (whole body)
  • SAR: 1.23 W/kg average over time (whole body)
  • SAR: 0.41 W/kg average over time (whole body)
ばく露2: 1,747 MHz
Modulation type: pulsed
ばく露時間: repeated daily exposure, 2 h/day, 5 days/week, for 52 or 104 weeks
  • SAR: 4 W/kg average over time (whole body)
  • SAR: 1.33 W/kg average over time (whole body)
  • SAR: 0.44 W/kg average over time (whole body)

General information

The GSM and DCS experiments were conducted in adjacent rooms, each having 16 exposure units installed. A placement rotation scheme was applied to all rats in order to minimize dose differences due to signal differences within and between exposure units.

ばく露1

主たる特性
周波数 902 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 repeated daily exposure, 2 h/day, 5 days/week, for 52 or 104 weeks
Modulation
Modulation type pulsed
Additional information

GSM signal
ばく露装置
ばく露の発生源／構造
チャンバの詳細 The exposure unit for up to 17 animals consisted of a circular cascade of 17 electromagnetically isolated and resonant waveguides (terminated by stainless steel wires), all excited by one quarter-loop antenna placed in the center and providing uniform circular excitation (maximum deviation of isotropy of ±0.2 dB).
ばく露装置の詳細 Rats were individually restrained in horizontal position in metal-free polycarbonate tubes and were positioned in optimal H-polarization with their centers of mass at 150 ± 2 mm from the shortcut thus providing a reasonably homogeneous exposure for varying sizes. Missing animals were replaced with a dummy (container simulating the absorption characteristics) to minimise imbalances of the excitations.
Sham exposure A sham exposure was conducted.
Additional information The RF signals were generated by a digital GSM/DCS signal generator combined with a frame generator and control unit [Kainz et al., 2006]. Each slot was modulated with a random code.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 3.7 W/kg average over time 測定値および計算値 whole body -
SAR 1.23 W/kg average over time 測定値および計算値 whole body -
SAR 0.41 W/kg average over time 測定値および計算値 whole body -
Additional parameter details

Each exposure session was divided into three phases of 40 min: (1) GSM Basic (non-DTX) mode with one slot active per basic frame and each 26th basic frame idle. (2) GSM Talk mode consisting of temporal changes between the non-DTX (average 10.8 s) and DTX (average 5.6 s) modes. (3) GSM Environment mode consisting of a GSM Talk signal further amplitude-modulated by a power control function statistically based on measurements performed by France Telecom [Wiart et al., 2000]. The peak (slot-averaged) SAR level for all three phases was the same, however, the resulting average SARs varied: 100% (GSM Basic), 70% (GSM Talk), and 26% (GSM Environment). The SAR values indicated above are those for GSM Basic. The SAR levels in the GSM study had to be decreased in three steps over time since the body weight increase of the rats was greater than predicted and the available power was insufficient to maintain 4 W/kg. So, the SAR (GSM Basic) averaged over the entire exposure period was only 3.7 W/kg for the high-dose group. The SAR values for the medium- and low-dose groups were also adjusted accordingly to keep the target ratio of three between the dose groups.

測定および計算の詳細

During exposure, the electric field strength inside the waveguide cavity was monitored and controlled almost continuously at two different places. A new methodology was used to obtain comprehensive dosimetric information for whole-body and peak spatial SAR as well as the averaged values for the most important organs including the uncertainty as well as the instant and life-long variations [Kuster et al., 2006].

ばく露2

主たる特性
周波数 1,747 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 repeated daily exposure, 2 h/day, 5 days/week, for 52 or 104 weeks
Modulation
Modulation type pulsed
Additional information

DCS signal
ばく露装置
ばく露の発生源／構造
  • E1と同じ装置
Sham exposure A sham exposure was conducted.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 4 W/kg average over time 測定値および計算値 whole body -
SAR 1.33 W/kg average over time 測定値および計算値 whole body -
SAR 0.44 W/kg average over time 測定値および計算値 whole body -
Additional parameter details

The peak (slot-averaged) SAR level for all three phases was the same (33.2 W/kg for the high-dose group), however, the resulting average SARs varied: 100% (GSM Basic), 70% (GSM Talk), and 26% (GSM Environment). The SAR values indicated above are those for GSM Basic.

Reference articles

  • Kainz W et al. (2006): [高効率、国家毒性プログラム（NTP）との互換性と十分に特徴付けられたばく露を実現する新しいラット用全身暴露実験装置の開発]
  • Kuster N et al. (2006): [In vivo研究におけるドジメトリーと不確実性と変動性の処理方法]
  • Wiart J et al. (2000): [GSM 携帯電話での無線周波ばく露に対する電源制御と不連続な通信の影響分析]

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 study produced no evidence that radiofrequency electromagnetic field exposure under these conditions had any effect on the incidence or severity of any non-neoplastic condition or the type, incidence, multiplicity and latency of any neoplastic lesion.

研究の種別:

研究助成

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