ROLE OF FIELD INTENSITY IN THE BIOLOGICAL EFFECTIVENESS OF MILLIMETERWAVES AT A RESONANCE FREQUENCY

The study replicated the effect of low-intensity millimeter waves (MMW ) on isolated nerve function and characterized its dependence on radia tion intensity. MMW exposures lasted for 23 min at 0.02, 0.1, 0.5, or 2.6 mW cm(-2) (41.34 GHz) and were accompanied by a high-rate electric al stimulation of the nerve (HRS, 20 twin pulses s(-1), 9 ms interpuls e interval). MMW had no effect on the conditioning compound action pot entials (CAPs), but significantly attenuated the HRS-caused decrease o f the test CAPs, The magnitude of this effect was virtually the same ( 20-25%) at field intensities of 0.02, 0.1, and 2.6 mW cm(-2). irradiat ion at 0.5 mW cm(-2), however, did not produce statistically significa nt changes. The results are consistent with our earlier observations o f this MMW effect and provide further evidence for its nonthermal mech anism. (C) 1997 Elsevier Science S.A.