Schmid G, Uberbacher R, Samaras T
Austrian Research Centers GmbH-ARC, A-2444 Seibersdorf, Austria.
Radiat Prot Dosimetry. 2007;124(1):15-20. doi: 10.1093/rpd/ncm335. Epub 2007 Jun 26.
In order to enable a detailed numerical radio frequency (RF) dosimetry and the computations of RF-induced temperature elevations, high-resolution (0.1 mm) numerical models of the human eye, the inner ear organs and the pineal gland were developed and inserted into a commercially available head model. As radiation sources, generic models of handsets at 400, 900 and 1850 MHz operating in close proximity to the head were considered. The results, obtained by finite-difference time domain-based computations, showed a highly heterogeneous specific absorption rate (SAR) distribution and SAR-peaks inside the inner ear structures; however, the corresponding RF-induced temperature elevations were well below 0.1 degrees C, when considering typical output power values of handheld devices. In case of frontal exposure, with the radiation sources approximately 2.5 cm in front of the closed eye, maximum temperature elevations in the eye in the range of approximately 0.2-0.6 degrees C were found for typical device output powers. A reduction in tissue perfusion mainly affected the maximum RF-induced temperature elevation of tissues deep inside the head. Similarly, worst-case considerations regarding pulsed irradiation affected temperature elevations in deep tissue significantly more than in superficial tissues.
为了实现详细的数值射频（RF）剂量测定以及对射频诱导的温度升高进行计算，开发了人眼、内耳器官和松果体的高分辨率（0.1毫米）数值模型，并将其插入到一个商用头部模型中。作为辐射源，考虑了在头部附近工作的400、900和1850兆赫兹手机的通用模型。通过基于时域有限差分的计算得到的结果表明，内耳结构内部的比吸收率（SAR）分布高度不均匀且存在SAR峰值；然而，考虑到手持设备的典型输出功率值时，相应的射频诱导温度升高远低于0.1摄氏度。在正面暴露的情况下，辐射源位于闭眼前方约2.5厘米处，对于典型的设备输出功率，眼睛中的最高温度升高在约0.2 - 0.6摄氏度范围内。组织灌注的减少主要影响头部深处组织的最大射频诱导温度升高。同样，关于脉冲照射的最坏情况考虑对深部组织温度升高的影响明显大于对浅表组织的影响。
