Study type: Medical/biological study (experimental study)

Chronic, low-level (1.0 W/kg) exposure of mice prone to mammary cancer to 2450 MHz microwaves med./bio.

By: Frei MR, Jauchem JR, Dusch SJ, Merritt JH, Berger RE, Stedham MA
Published in: Radiat Res 1998; 150 (5): 568-576
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Aim of study (acc. to author)

To determine whether chronic, low-level exposure of mammary-tumor-prone mice to 2450 MHz radiofrequency radiation promotes an earlier onset (decreased latency), a greater total incidence, or a faster growth rate of mammary tumors.

Background/further details

The current study was designed to replicate a previous study (publication 3413) but to increase the SAR from 0.3 W/kg to 1.0 W/kg to determine if a threshold SAR effect exists.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: CW
Exposure duration: repeated daily exposure, 20 h/day, for 78 weeks

Exposure 1

Main characteristics
Frequency 2.45 GHz
Type
Charakteristic
  • guided field
Polarization
  • circular
Exposure duration repeated daily exposure, 20 h/day, for 78 weeks
Modulation
Modulation type CW
Exposure setup
Exposure source
Chamber The waveguides were housed in a room (5.49 m square) maintained at 24 ± 1°C and 50 ± 5% humidity.
Setup The cages housing two mice were made of Plexiglas with 5-mm Plexiglas rods on the floor spaced 0.75 cm apart and oriented perpendicular to the individual waveguide (a copper mesh enclosure) [Guy et al., 1979]. They provided a floor area of 143 cm² per animal.
Sham exposure A sham exposure was conducted.
Additional info Mice were randomly assigned to RF and sham exposure groups (100 each).
Parameters
Measurand Value Type Method Mass Remarks
power 140 mW mean measured - input power per waveguide
SAR 1 W/kg mean measured and calculated whole body -
Additional parameter details

The ambient 60 Hz electric fields were negligible; the ambient magnetic fields were 0.13 µT (mean of 75 measurements ranging from 0.03 to 0.33 µT).

Measurement and calculation details

Transmitter output, forward, reflected, and absorbed powers were monitored and stored. As in the previous study, the waveguides were characterised by extensive dosimetric measurements using and comparing calorimetric and differential power techniques, both performed simultaneously using the same animals in the same positions.

Reference articles

  • Guy AW et al. (1979): Circularly polarized 2450 MHz waveguide system for chronic exposure of small animals to microwaves

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

The results indicate that under these experimental conditions, long-term, low-level exposure of mammary-tumor-prone mice to 2450 MHz radiofrequency did not affect mammary tumor incidence, latency to mammary tumor onset, mammary tumor growth rate, or survivorship when compared with sham-irradiated controls. Histopathological examination revealed no differences in numbers of malignant, metastatic, or benign neoplasms between the two groups.

Study character:

Study funded by

Replicated studies

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