Study type: Medical/biological study (experimental study)

Effects of Hyperthermia Induced by Microwave Irradiation on Brain Development in Mice. med./bio.

Published in: J Radiat Res 1992; 33 (1): 1-10

Aim of study (acc. to author)

To compare the effects of a brief maternal hyperthermia induced by microwave irradiation during pregnancy on mouse brain development with the thermal effects induced by a 42°C hot water immersion.

Background/further details

Pregnant mice were exposed to microwave on day 13 of gestation and the number of pycnotic cells in the ventricular zone of the telencephalon was examined 9 h after treatment.



Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: pulsed
Exposure duration: 15 or 20 min on day 13 of gestation
  • SAR: 480 mW/g mean (cf. remarks) (+-120mW/g)

General information

external antenna

Exposure 1

Main characteristics
Frequency 2.45 GHz
Exposure duration 15 or 20 min on day 13 of gestation
Modulation type pulsed
Pulse width 15 s
Additional info

15s on off scedule

Exposure setup
Exposure source
  • clinical hypertermia system, external antenna
Distance between exposed object and exposure source 0.275 m
Additional info mice (head covered with aluminium foil fixed styrofoam)
Measurand Value Type Method Mass Remarks
SAR 480 mW/g mean measured cf. remarks +-120mW/g

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 highest maternal core temperature during irradiation did not exceed 42.5°C. The respective incidence of pycnotic cells in the group exposed to microwaves for 15 and 20 min were 1.83% and 3.06%. Microwave exposure for 20 min had an effect that was comparable to that of immersion in 42°C hot water for 15 min. In addition, some mice were examined on day 18 of gestation, and some of their offspring were examined at 6 weeks of age in an investigation of long-term effects. Brain weight for the animals exposed to microwaves for 20 min was significantly lower than for the control group. And the numerical density of the neurons in the cerebrum was higher. The authors concluded that microwave exposure at the dose tested mainly has a thermal effect.

Study character:

Study funded by

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