ADI-FDTD 方法在乳腺癌检测正向计算中的应用

摘要

传统的时域有限差分(Finite-Difference Time-Domain,FDTD)算法受到稳定性条件的制约,时间步长受限于空间网格的尺寸。医学应用讲究即时性,为提高成像的速度,文中采用无条件稳定的交替隐式时域有限差分(Alternating-Direction Implicit Finite-Difference Time-Domain,ADI-FDTD)算法替代传统的 FDTD 算法进行正向计算,通过实验得出采用 ADI-FDTD 算法在保证精度的前提下,计算时间可缩短为 FDTD 算法的四分之一,为乳腺癌微波即时成像提供了可能。%In the conventional finite-difference time-domain (FDTD)method,fine cells reduce the time-step size due to the Courant-Friedrich-Levy(CFL)stability condition,which results in an increase in computational effort,such as the central processing unit (CPU)time.In the alternating-direction implicit finite-difference time-domain(ADI-FDTD)method,a larger time-step size than allowed by the CFL stabili-ty condition limitation can be set because the algorithm of this method is unconditionally stable.Conse-quently,an increase in computational efforts caused by fine cells can be prevented.The simulation experi-ments data by the ADI-FDTD method were compared with that by the conventional FDTD method.The results show that simulation field by ADI-FDTD method agree quite well with that by the FDTD method, but the required CPU time can be much shorter than that for the FDTD method.