Study type: Medical/biological study (experimental study)

Lymphomas in Eµ-Pim1 transgenic mice exposed to pulsed 900 MHz electromagnetic fields med./bio.

Published in: Radiat Res 1997; 147 (5): 631-640

Aim of study (acc. to author)

To determine whether long-term exposure to pulse-modulated radiofrequency fields similar to those used in digital mobile telecommunications would increase the incidence of lymphoma in Eµ-Pim1 transgenic mice (expressing an activated Pim1 oncogene in their lymphoid cells).



Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: repeated daily exposure for 30 min every 12 h for up to 18 months
  • power: 9.1 W mean
  • SAR: 4.2 W/kg average over mass (whole body) (0.008-4.2 W/kg for an individual mouse)
  • SAR: 1.4 W/kg average over mass (whole body) (0.13-1.4 W/kg for groups of five mice)
  • power density: 13 W/m² maximum (2.6 - 13 W/m²)

Exposure 1

Main characteristics
Frequency 900 MHz
Exposure duration repeated daily exposure for 30 min every 12 h for up to 18 months
Modulation type pulsed
Pulse width 0.6 ms
Duty cycle 13 %
Repetition frequency 217 Hz
Exposure setup
Exposure source
  • monopole
  • RF generator
Distance between exposed object and exposure source 0.65 m
Chamber The exposure room was 2.6 m long x 2.2 m wide x 2.45 high. Sham exposed mice were housed in a separate room, only 1.8 m wide. The rooms were lined with overlapping sheets of 1-mm aluminium (-40 dB at 900 MHz). Each room contained a vertical ground plane (2.5 m x 2.2 m), running parallel to the wall, with a quarter-wave monopole antenna at the center.
Setup Twenty Lucite® stands (15 cm x 30 cm) for mouse cages were mounted in a circular array perpendicular to the ground plane with their centers 0.65 m from the antenna. The mice were housed in groups of five in 18 x 15 x 30 cm filter-top transparent polycarbonate cages with a perforated glass lid.
Sham exposure A sham exposure was conducted.
Additional info To ensure equal average exposures, cages were moved clockwise to the next position twice weekly.
Measurand Value Type Method Mass Remarks
power 9.1 W mean measured - -
SAR 4.2 W/kg average over mass measured and calculated whole body 0.008-4.2 W/kg for an individual mouse
SAR 1.4 W/kg average over mass measured and calculated whole body 0.13-1.4 W/kg for groups of five mice
power density 13 W/m² maximum measured - 2.6 - 13 W/m²

Reference articles

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)

Lymphoma risk was found to be significantly higher in the exposed mice than in the controls.

Study character:

Study funded by

Replication studies

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