Study type: Medical/biological study (experimental study)

Hyperthermia in radiofrequency-exposed rhesus monkeys: a comparison of frequency and orientation effects. med./bio.

Published in: Radiat Res 1985; 102 (1): 59-70

Aim of study (acc. to author)

To determine the effect on body temperature and plasma cortisol levels of whole body exposure of rhesus monkeys to a near-resonant frequency. Monkeys were exposed for 4 hr to 225 MHz, electric field oriented parallel to the long axis of the body (225 MHz-E), and to 225 MHz, magnetic field orientation (225 MHz-H), or to 1290 MHz, electric field orientation. On a separate occasion, the monkeys were irradiated at night to 225 MHz-E.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 225 MHz
Modulation type: CW
Exposure duration: 4 h during the day; some exposures also took place during the night for 4 h at 5 mW/cm?
Exposure 2: 225 MHz
Modulation type: CW
Exposure duration: 4 h
Exposure 3: 1.29 GHz
Modulation type: pulsed
Exposure duration: 4 h

Exposure 1

Main characteristics
Frequency 225 MHz
Type
Charakteristic
Polarization
Exposure duration 4 h during the day; some exposures also took place during the night for 4 h at 5 mW/cm?
Additional info Electric field oriented parallel to the long axis of the body.
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 2.4 m
Chamber Anechoic chamber/ 3.3 m x 3.3 m x 6.7 m
Setup Monkeys restrained in a foamed polystyrene chair in such a way that the chest was exposed.
Additional info To achieve 15 mW/cm? the animal had to move closer to the antenna (170 cm).
Parameters
Measurand Value Type Method Mass Remarks
power density 12 W/m² mean measured - 25 W/m?, 50 W/m?, 75 W/m?, 100 W/m? and 150 W/m?

Exposure 2

Main characteristics
Frequency 225 MHz
Type
Charakteristic
Polarization
Exposure duration 4 h
Additional info H-field oriented parallel to the long axis of the body.
Modulation
Modulation type CW
Exposure setup
Exposure source
Distance between exposed object and exposure source 2.4 m
Chamber Anechoic chamber/ 3.3 m x 3.3 m x 6.7 m
Setup Monkeys restrained in a foamed polystyrene chair in such a way that the chest was exposed.
Parameters
Measurand Value Type Method Mass Remarks
power density 50 W/m² mean measured - -

Exposure 3

Main characteristics
Frequency 1.29 GHz
Type
Charakteristic
Polarization
Exposure duration 4 h
Additional info E-field parallel to the long axis of the animals body.
Modulation
Modulation type pulsed
Pulse width 3 µs
Packets per second 330
Exposure setup
Exposure source
Distance between exposed object and exposure source 2 m
Chamber 20 cm pyramidal lined MW absorber chamber/ 2.4 m x 2.4 m x 4.9 m
Setup Monkeys restrained in a foamed polystyrene chair.
Parameters
Measurand Value Type Method Mass Remarks
power density 200 W/m² mean measured - 280 W/m? and 380 W/m?

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

Average rectal temperature increases for day exposure to 225 MHz-E were 0.4 and 1.7°C for 4-hr exposures to 2.5 and 5.0 mW/cm². No alterations in cortisol contents occurred during any exposures to 5 mW/cm² or less. Night exposures to 5 mW/cm² at 225 MHz-E raised mean rectal temperature 2.1°C. Exposure to 5 mW/cm² at 225 MHz-H for 4 hr resulted in a 0.2°C rise in mean rectal temperature. For 4 hr of 1290-MHz exposure to 20, 28, or 38 mW/cm², the mean body temperature increases were 0.4, 0.7, and 1.3°C, respectively.
The degree of hyperthermia caused by radiofrequency exposure was shown to be frequency and orientation dependent for equivalent power densities.

Study character:

Study funded by