Thermal and physiological changes in rats exposed to CW and pulsed 2.8 GHz radiofrequency radiation in E and H orientations.

Ketamine-anesthetized Sprague-Dawley rats were exposed in both E and H orientations to far-field 2.8 GHz continuous-wave (CW) and pulsed (0.5 microseconds, 500 pps) radiofrequency radiation (RFR) at equivalent whole-body average specific absorption rates (SAR) of approximately 14 W/kg. Intermittent irradiation was performed in all four exposure conditions, in the same animal, to repeatedly increase colonic temperature from 38.5 to 39.5 degrees C. Tympanic, subcutaneous (sides toward and away from RF sources), colonic, and tail temperatures, electrocardiogram, arterial blood pressure, and respiratory rate were continuously recorded. The results revealed no significant difference between the thermal effects of CW and pulsed RFR exposure. The results did show significant differences between the thermal effects of E- and H-orientation exposure. H-orientation irradiation produced significantly faster colonic temperature increases and, with the exception of the tail, produced significantly greater localized heating in the anesthetized rat, and higher local SAR in rat carcasses than did E-orientation exposure. Under all exposure conditions, heart rate and blood pressure increased significantly during irradiation and returned to baseline when exposure was discontinued. Respiratory rate remained unchanged during irradiation. There were no significant differences between the effects of E- and H-orientation exposure, or between CW and pulsed irradiation, upon heart rate, blood pressure, and respiratory rate.