Han Jijun, Yang Deqiang, Sun Houjun, Xin Sherman Xuegang
a Department of Medical Engineering, School of Biomedical Engineering , Southern Medical University , Guangzhou , P. R. China.
b Guangdong Provincial Key Laboratory of Medical Image Processing, Southern Medical University , Guangzhou , P. R. China.
Electromagn Biol Med. 2017;36(2):169-176. doi: 10.1080/15368378.2016.1240687. Epub 2016 Oct 24.
Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed. A Huygens' equivalent surface is established as a bridge to combine the inverse and FDTD method. Distribution of the radiofrequency (RF) magnetic field on the Huygens' equivalent surface is obtained using the FDTD method by considering the complex field-tissue interactions within the human body model. The obtained magnetic field distributed on the Huygens' equivalent surface is regarded as the next target. The current density on the designated source surface is derived using the inverse method. The homogeneity of target magnetic field and specific energy absorption rate are calculated to verify the proposed method.
逆方法本质上适用于计算与不规则结构电磁目标场相关的源电流密度分布。然而，目前形式的逆方法无法计算复杂的场-组织相互作用。提出了一种新颖的混合逆/时域有限差分（FDTD）方法，该方法可以计算与不规则结构电磁目标场相关的源电流密度逆设计中的复杂场-组织相互作用。建立惠更斯等效面作为结合逆方法和FDTD方法的桥梁。通过考虑人体模型内的复杂场-组织相互作用，使用FDTD方法获得惠更斯等效面上的射频（RF）磁场分布。将在惠更斯等效面上获得的磁场分布视为下一个目标。使用逆方法推导指定源表面上的电流密度。计算目标磁场的均匀性和比吸收率以验证所提出的方法。
