Hirata A, Watanabe S, Fujiwara O, Kojima M, Sasaki K, Shiozawa T
Nagoya Institute of Technology, Japan.
Phys Med Biol. 2007 Nov 7;52(21):6389-99. doi: 10.1088/0031-9155/52/21/003. Epub 2007 Oct 11.
This study investigated the temperature elevation in the eye of anatomically based human head models for plane-wave exposures. The finite-difference time-domain method is used for analyzing electromagnetic absorption and temperature elevation. The eyes in the anatomic models have average dimensions and weight. Computational results show that the ratio of maximum temperature in the lens to the eye-average SAR (named 'heating factor for the lens') is almost uniform (0.112-0.147 degrees C kg W(-1)) in the frequency region below 3 GHz. Above 3 GHz, this ratio increases gradually with an increase of frequency, which is attributed to the penetration depth of an electromagnetic wave. Particular attention is paid to the difference in the heating factor for the lens between this study and earlier works. Considering causes clarified in this study, compensated heating factors in all these studies are found to be in good agreement.
本研究调查了基于解剖学的人体头部模型眼睛在平面波照射下的温度升高情况。采用时域有限差分法分析电磁吸收和温度升高。解剖模型中的眼睛具有平均尺寸和重量。计算结果表明,在3 GHz以下的频率区域,晶状体中的最高温度与眼睛平均比吸收率的比值(称为“晶状体加热因子”)几乎是均匀的(0.112 - 0.147℃·kg·W⁻¹)。在3 GHz以上,该比值随频率增加而逐渐增大,这归因于电磁波的穿透深度。特别关注了本研究与早期工作中晶状体加热因子的差异。考虑到本研究中阐明的原因,发现所有这些研究中的补偿加热因子吻合良好。