Study type: Medical/biological study (experimental study)

Chronic exposure to a GSM-like signal (mobile phone) does not stimulate the development of DMBA-induced mammary tumors in rats: results of three consecutive studies. med./bio.

Published in: Radiat Res 2002; 157 (2): 183-190

Aim of study (acc. to author)

To analyse the effect of radiofrequency fields on 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary cancers in female Sprague-Dawley-rats, which is an accepted model for human breast cancer.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: nearly continuous until the largest tumour reached a diameter of 1-2 cm
  • power density: 100 µW/cm² mean (± 3 dB)
  • SAR: 130 mW/kg average over mass (whole body) (32.5-130 mW/kg for young rats of 150 g)
  • SAR: 70 mW/kg average over mass (whole body) (17.5-70 mW/kg at 300 g)
  • SAR: 60 mW/kg average over mass (whole body) (15-60 mW/kg for older rats of 400 g)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
Polarization
  • circular
Exposure duration nearly continuous until the largest tumour reached a diameter of 1-2 cm
Modulation
Modulation type pulsed
Pulse width 577 µs
Repetition frequency 217 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 130 cm
Chamber The animals in the RF-field-exposed and sham-exposed groups were kept in identical chambers. The five chambers used for sham and RF exposure, respectively, were placed in two separate air-conditioned, adjacent rooms of the same dimensions. Exposure chambers (90 x 90 x 187 cm) were made from sheet steel and had a lining of absorbing material on the walls and the bottom. Each chamber contained in its bottom part a Plexiglas cage of 0.4 m² x 20 cm equipped with three stainless steel nipples for drinking and covered by a perforated Plexiglas lid. The top as well as the lower front and back sides of the chamber underneath the animal cage were kept open for ventilation but covered with wire netting to suppress leakage of the EMF.
Setup Within the exposure chamber, the animal cage was located in the far field of a flat spiral antenna which was at a distance of 130 cm from the bottom of the cage and emitted a clockwise circularly polarized RF signal.
Additional info Exposure was interrupted once daily for about 10 to 20 min for feeding and inspection of animals, 3 to 4 h once weekly for tumour palpation, 1 to 2 h three times weekly for cleaning of cages, and 4 to 5 h once per month for servicing the exposure devices.
Parameters
Measurand Value Type Method Mass Remarks
power density 100 µW/cm² mean measured - ± 3 dB
SAR 130 mW/kg average over mass measured and calculated whole body 32.5-130 mW/kg for young rats of 150 g
SAR 70 mW/kg average over mass measured and calculated whole body 17.5-70 mW/kg at 300 g
SAR 60 mW/kg average over mass measured and calculated whole body 15-60 mW/kg for older rats of 400 g

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The radiofrequency field did not affect the development of DMBA-induced mammary tumors, but a statistically significantly delayed median latency was found for malignant tumors in one of three experiments.

Study character:

Study funded by

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