title: Computational modeling of temperature elevation and thermoregulatory response in the brains of anesthetized rats locally exposed at 1.5 GHz.
abstract: The dominant effect of human exposures to microwaves is caused by temperature elevation ('thermal effect'). In the safety guidelines/standards, the specific absorption rate averaged over a specific volume is used as a metric for human protection from localized exposure. Further investigation on the use of this metric is required, especially in terms of thermophysiology. The World Health Organization (2006 RF research agenda) has given high priority to research into the extent and consequences of microwave-induced temperature elevation in children. In this study, an electromagnetic-thermal computational code was developed to model electromagnetic power absorption and resulting temperature elevation leading to changes in active blood flow in response to localized 1.457 GHz exposure in rat heads. Both juvenile (4 week old) and young adult (8 week old) rats were considered. The computational code was validated against measurements for 4 and 8 week old rats. Our computational results suggest that the blood flow rate depends on both brain and core temperature elevations. No significant difference was observed between thermophysiological responses in 4 and 8 week old rats under these exposure conditions. The computational model developed herein is thus applicable to set exposure conditions for rats in laboratory investigations, as well as in planning treatment protocols in the thermal therapy.
authors.affiliation: Department of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan. ahirata@nitech.ac.jp
authors.forename: Akimasa
authors.initials: A
authors.lastname: Hirata
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Masuda
authors.forename: Yuya
authors.initials: Y
authors.lastname: Kanai
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Asai
authors.forename: Osamu
authors.initials: O
authors.lastname: Fujiwara
authors.forename: Takuji
authors.initials: T
authors.lastname: Arima
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kawai
authors.forename: Soichi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lagroye
authors.forename: Bernard
authors.initials: B
authors.lastname: Veyret
mesh_terms: D000375:Aging / Q000502:physiology / Q000528:radiation effects; D000758:Anesthesia; D000818:Animals; D001833:Body Temperature Regulation / Q000528:radiation effects*; D001921:Brain / Q000098:blood supply / Q000502:physiology* / Q000528:radiation effects*; D002560:Cerebrovascular Circulation / Q000528:radiation effects; D003198:Computer Simulation; D006801:Humans; D008297:Male; D008872:Microwaves / Q000009:adverse effects*; D011829:Radiation Dosage; D051381:Rats; D017207:Rats, Sprague-Dawley; D013696:Temperature