ID Number		1567
Study Type		Engineering & Physics
Model		434, 775, 915, 2450 MHz (CW) exposure to animal models and evaluation of SAR and "hot spots"
Details		Phantoms containing muscle-equivalent material were exposed to 434 or 915 MHz (CW) MW for 15-60 seconds and analyzed by thermography to determine the field-perturbing effects of metallic thermistors and thermocouples. Probes and catheters produced changes in heating pattern of up to 20%. Bare needle implants produced a hot spot at the tip at 915 MHz in the center of the field, or two elliptical side loops as the needle was pushed beyond the center. Thermistors and thermocouples in plastic catheters produced similar patterns. When probes were placed perpendicular to the E-field, minimal changes in the heating pattern were observed. Fiber optic probes produced small temperature decreases along the thermometer track at a depth of 2 cm, and minimal shifts in heating pattern otherwise. Thermocouples tested at 434 MHz showed perturbations at 2 cm, and variations were minimal when placed at different locations and orientations in the E field. In general, changes in heating pattern were asymmetrical and usually greater when probes were inserted at 45 or 90 degrees to the E field. In birds (parakeets, quail, pigeons, chickens, turkeys) and phantom spheres of containing muscle-equivalent material were exposed to 775, 915, and 2450 MHz (CW) MW, SAR patterns were determined for different mass and geometry and varied markedly from those obtained in phantom spheres of similar mass. In birds, peak SARs 10-fold higher than average were observed in the head and neck (up to 10 x or more). In flying position, SAR at 2450 MHz was maximal in the wing tips, followed by the proximal wing, neck, and body. In live birds, behavioral responses to thermal MW exposure included beak opening, swallowing, throat quivering, head shaking, feather fluffing, tail extension, wing drooping, wing spreading, panting, rapid grooming, generation of sounds, and collapsing. In a similar study (Bioelectromagnetics (1985) 6(1):73-88), Sprague Dawley rats were exposed to 2450 MHz MW and SAR in the head (8 positions), tail, and whole body (3 positions) was determined. The tail had the highest SAR as well as the highest variation. The highest SAR in the brain was in the anterior hypothalamus and olfactory tubercle, and lowest in the cortical areas.
Findings		Not Applicable to Bioeffects
Status		Completed With Publication
Principal Investigator		Motorola, Ft Lauderdale, FL, USA - ecc017@email.mot.com
Funding Agency		AF, USA
Country		UNITED STATES
References		Chan, KW et al. Int J Hyperthermia, (1988) 4:447-456 Chan, KW et al. Int J Hyperthermia, (1988) 4:699-702 Chou, CK et al. J Microw Power Electromagn Energy, (1985) 20:75-84
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