Establishment of the method for quantitative measurement of SAR value using a high molecular gel phantom

利用一种云度随温度变化的高分子凝胶体模，发展了一种可视化或三维测量人体吸收能量的新技术。该凝胶模体除含有盐、糖和酒精外，还含有非离子表面活性剂。通过改变这些浓度，可以将体模的电、光和机械属性调整到所需的值。由于非离子表面活性剂的分离，吸收电磁功率而超过被称为浊点的特定温度的区域变得白色和不透明。因此，可以使用凝胶体模来可视化吸收的能量。在一些常用的典型频率下，已经给出了一系列标准体模。也就是说，已经给出了体模组成与电、机械和热性能等物理性质之间的关系，基于这种知识，可以开发各种体模。只要体模的热传导可以忽略不计，SAR值表示体模的云区和非云区之间的边界上的小区域吸收的平均功率密度。此外，可以用激光测距仪测量边界上小区域的坐标。由此得出结论，局部合成孔径雷达是以三维方式可见或可测量的。基于FD-TD的数值分析结果表明了该方法的有效性。

A new technique for visualization or three dimensional measurement of power absorbed by the human body has been developed by using a high molecular gel phantom whose cloudiness varies with the change in temperature. The gel phantom contains non ionic surface active agent in addition to salt, sugar and alcohol. The electric-, optical-, and mechanical-property of the phantom are adjusted to the desired values by varying those concentration. The region which exceeds a specific temperature called clouding point by absorbing electromagnetic power becomes white and opaque due to segregation of non ionic surface active agent. Therefore, the absorbed power can be visualized by using the gel phantom.A series of standard phantoms have been given at some typical frequencies which are commonly used for various purposes. That is, relationships between the phantom composition and physical property such as electric-, mechanical- and thermal properties have been given, Based on this knowledge, various kinds of phantoms can be developed.The SAR value represents average power density absorbed by a small region on the boundary between the clouded- and nonclouded-region of the phantom as long as thermal conduction of the phantom is negligible. Furthermore, the coordinates of the small region on the boundary can be measured with a laser range finder. Thus, it is concluded that local SAR is made visible or measurable in three dimensional ways. The validity of the method of SAR measurement has been shown by FD-TD based numerical analysis.