Study type: Medical/biological study (experimental study)

Physiological effects of 2.8 GHz radio-frequency radiation: a comparison of pulsed and continuous-wave radiation med./bio.

By: Frei M, Jauchem JR, Heinmets F
Published in: J Microw Power Electromagn Energy 1988; 23 (2): 85-93
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Aim of study (acc. to author)

To compare the acute effects of continuous wave (CW) and pulsed 2.8 GHz radiofrequency irradiation at several equivalent power levels upon heating and cooling responses and related physiological processes in anesthetized rats.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.8 GHz
Modulation type: CW
Exposure duration: 3 to 4 h ( the RF irradiation was applied in 1°C cycles and a total of 7 cycles were applied)
Exposure 2: 2.8 GHz
Modulation type: pulsed
Exposure duration: 3 to 4 h ( the RF irradiation was applied in 1°C cycles and a total of 7 cycles were applied)

Exposure 1

Main characteristics
Frequency 2.8 GHz
Charakteristic
Exposure duration 3 to 4 h ( the RF irradiation was applied in 1°C cycles and a total of 7 cycles were applied)
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup The animal was placed on a Plexiglas holder in the chamber with their long body axis parallel to the magnetic field and the left side towards the antenna
Parameters
Measurand Value Type Method Mass Remarks
power density 450 W/m² mean measured - 12.6 W/kg corresponding SAR
power density 600 W/m² mean measured - 16.8 W/kg corresponding SAR
power density 300 W/m² mean measured - 8.4 W/kg corresponding SAR

Exposure 2

Main characteristics
Frequency 2.8 GHz
Charakteristic
Exposure duration 3 to 4 h ( the RF irradiation was applied in 1°C cycles and a total of 7 cycles were applied)
Modulation
Modulation type pulsed
Pulse width 2 µs
Repetition frequency 500 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power density 450 W/m² mean measured - 12.6 W/kg corresponding SAR
power density 750 W/m² mean measured - 21 W/kg corresponding SAR
power density 300 W/m² mean measured - 8.4 W/kg corresponding SAR
power density 600 W/m² mean measured - 16.8 W/kg corresponding SAR

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

The time required to effect a 1°C colonic temperature increase varied inversely with the average power density used during irradiation; however, the rate of cooling was independent of the heating rate. During exposure to pulsed radiofrequency irradiation, heart rate increased significantly at average power densities above 30 mW/cm²; heart rate increase during continuous wave irradiation was not significant. Heart rate returned to baseline when irradiation was discontinued. Blood pressure and respiratory rate did not significantly change during exposure. Pulsed radiofrequency irradiation caused a significantly greater increase in subcutaneous and tympanic temperatures than did continuous wave exposure; however, no significant difference was found between the effects of continuous wave or pulsed radiofrequency irradiation upon the rats' colonic temperature responses (heating and cooling time), heart rate, blood pressure, and respiratory rate.

Study character: