Study type: Medical/biological study (experimental study)

Measurement of DNA damage after exposure to 2450 MHz electromagnetic radiation med./bio.

By: Malyapa RS, Ahern EW, Straube WL, Moros EG, Pickard WF, Roti Roti JL
Published in: Radiat Res 1997; 148 (6): 608-617
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Aim of study (acc. to author)

To determine if exposure of cultured mammalian cells to 2450 MHz radiation causes DNA damage.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2,450 MHz
Modulation type: CW
Exposure duration: continuous for 2, 4, and 24 h
  • SAR: 0.75 W/kg mean (± 0.39 W/kg)
  • SAR: 1.93 W/kg mean (± 0.99 W/kg)

Exposure 1

Main characteristics
Frequency 2,450 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 2, 4, and 24 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 292 mm
Chamber The warm room accommodated up to 10 radial transmission lines (RTLs), the culture medium in which was maintained at 37.0 ± 0.3°C. The RTL consisted of a parallel-plate region formed by an aluminium bottom plate and a hinged lightweight metal-faced composite top plate and terminated radially by MW-absorbing layers backed by a lamina of perforated aluminium [Moros et al., 1999].
Setup Each RTL could hold 16 T-75 flasks each containing 40 ml of medium (1200 cm² of culture area in total) at a radius of 292 mm from the central conical antenna. The electric field of the waves propagating radially outward was perpendicular to the cell layer. The tangential magnetic field was perpendicular to the EF and the propagation direction.
Sham exposure A sham exposure was conducted.
Additional info Some cells were exposed for 2 h and incubated at 37°C for 4 h.
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.75 W/kg mean measured - ± 0.39 W/kg
SAR 1.93 W/kg mean measured - ± 0.99 W/kg
Additional parameter details

Positive controls were irradiated at melting ice temperature with low doses of 137Cs γ-rays at a dose rate of 6.55 cGy/min. In addition, every MW exposure experiment included a sample that was irradiated with 2 Gy of γ-rays at a dose rate of 1.1 Gy/min.

Measurement and calculation details

The RTLs were extensively characterised, and complete fine mapping of the SAR was done using a bowman probe at 18 points in over 64 individual measurements. SARs at the bottom of the flasks were determined using a fast temperature differential measurement technique [Pickard et al., 1999].

Reference articles

  • Moros EG et al. (1999): The radial transmission line as a broad-band shielded exposure system for microwave irradiation of large numbers of culture flasks
  • Pickard WF et al. (1999): Simplified model and measurement of specific absorption rate distribution in a culture flask within a transverse electromagnetic mode exposure system
  • Chou CK et al. (1996): Radio frequency electromagnetic exposure: tutorial review on experimental dosimetry

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

No significant differences were observed between the test groups and the controls after exposure to 2450 MHz CW (continuous wave) microwaves. Thus 2450 MHz exposure does not appear to cause DNA damage in cultured mammalian cells under these conditions.

Study character:

Study funded by

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