Department of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
Phys Med Biol. 2011 Dec 7;56(23):7639-57. doi: 10.1088/0031-9155/56/23/019.
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.
人类暴露于微波的主要影响是由温度升高引起的（“热效应”）。在安全指南/标准中，特定体积内的平均比吸收率被用作保护人体免受局部暴露的指标。需要进一步研究该指标的使用，特别是在热生理学方面。世界卫生组织（2006 年射频研究议程）高度重视研究儿童中微波引起的温升的程度和后果。在这项研究中，开发了一个电磁热计算代码，以模拟电磁功率吸收和由此产生的温度升高，导致在大鼠头部接受 1.457GHz 局部暴露时，主动血流发生变化。考虑了幼鼠（4 周龄）和年轻成年鼠（8 周龄）。该计算代码针对 4 周龄和 8 周龄大鼠的测量值进行了验证。我们的计算结果表明，血流速率取决于大脑和核心温度的升高。在这些暴露条件下，4 周龄和 8 周龄大鼠的热生理学反应没有明显差异。因此，本文开发的计算模型适用于为实验室研究中的大鼠设定暴露条件，以及在热疗中规划治疗方案。
