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.
Modulation type: CW
Modulation type: pulsed
|Pulse width||2 µs|
|Repetition frequency||500 Hz|
|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|
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.