电阻抗成像技术作为一种新兴的功能性医学成像技术具有广阔的应用前景。除了成像的空间分辨率不高之外,当前研究中普遍针对封闭场域成像的模式也是电阻抗成像技术推广到临床应用的一个不可忽视的障碍。在分析封闭式电阻抗成像临床应用局限性的基础上,提出了开放式电阻抗成像的思想,依据这一思想构建的开放式电阻抗成像系统能对局部浅层的生物组织给出有价值的电阻抗分布信息。给出了开放式电阻抗成像电磁场边值问题的数学模型,提出了边界约束问题的处理方法,并进行了初步的仿真和实验研究。结果表明,当目标位于体表下较浅部位时,成像具有较好的分辨率和定位准确度。
Electrical impedance tomography(EIT) has a wide application prospect as a new functional medical imaging technology.Besides the low spatial resolution of imaging,the imaging mode arming at closed region is also an unneglectable obstacle for the clinical application of EIT.In this paper,we proposed an idea of open electrical impedance tomography(OEIT) in order to overcome the limitation of the clinical application of closed EIT.The OEIT system constructed according to this idea provided valuable distribution information of electrical impedance for local subsurface biological tissues,which was more suitable for clinical application.The electromagnetic mathematical models of OEIT were presented and a method was proposed for solving the problem of boundary constrains.Furthermore,the preliminary simulations and experiments are conducted.Experiment results showed that the better resolution and positioning accuracy could be obtained when the object was at the shallower position below the surface.