模拟人体组织介电特性的介电材料研究

Study on the Dielectric Materials Mimicking the Dielectric Properties of Human Tissues

模拟人体组织相对介电常数和电导率的介电材料可用于分析1.5 T磁共振电特性断层成像技术的算法准确性和成像分辨率。为了得到各种人体组织模拟介电材料的具体组成,利用油、明胶、去离子水和氯化钠为主要成分制作了一组介电材料样本,其中油体积百分比范围为0%~80%,氯化钠浓度范围为0~1.40 g/100 m L。通过开端同轴线法测量这组介电材料样本在频率为64 MHz和温度为25℃时的介电特性,得到这组样本的电导率和相对介电常数变化范围分别为0.04~1.43S/m和12.6~83.4。利用非线性最小二乘拟合得到描述介电材料组成和其介电特性函数关系的经验公式。根据经验公式可以迅速得到各种人体组织模拟介电材料的组成。

The dielectric materials mimicking the relative permittivity and conductivity of various human tissues can be used to analyze the algorithm accuracy and image resolution of the magnetic resonance electric property tomography （MR EPT） technique at 1.5 T. In order to obtain the specific compositions of various human tissue- mimicking dielectric materials, a set of dielectric material samples were produced using oil, gelatin, deionized wa- ter and sodium chloride as chief ingredients, the ranges of oil volume percentage and NaC1 concentration were 0% ~ 80% and 0 ~ 1.40 g/100 mL respectively. The dielectric properties of these dielectric material samples were meas- ured using open-ended coaxial line method at the frequency of 64 MHz, and the measurement was taken under the temperature of 25 ℃. The ranges of conductivity and relative permittivity of the samples were 0. 04 - 1.43 S/m and 12.6- 83.4 respectively. Nonlinear least square fitting method was used to establish the empirical formulae be- tween the composition of dielectric material and its dielectric properties. According to the empirical formulae, the specific compositions of the dielectric materials mimicking various human tissues could be efficiently obtained.