Influences of Compound Electrode Parameter on Measurement Sensitivity and Reconstruction Quality in Electrical Impedance Tomography.

The electrode is the front-end of EIT system and directly contacts human body. The structure and parameter of the electrode greatly influence the original information extraction, real time property of the system and image resolving power, especially the information extraction of the center area where the EIT measurement sensitivity is poor. EIT electrode system is one of the most sensitive and the pivotal parts of EIT. The compound electrode has 4 structure parameters: the excitation electrode width, the measurement electrode width, the space between the excitation electrode and the measurement electrode, and the distance of two adjacent compound electrodes. For an EIT electrode system with certain boundary, when the electrode numbers and elements divided in FEM are determined, the sum of the electrode width and the distance of two adjacent electrodes is fixed too. Therefore only 3 among 4 structure parameters of the compound electrode are independent. The influences of the compound electrode parameters on the imaging quality and measurement sensitivity of EIT system are studied. The conclusion is that because of the circular boundary of EIT object, parameters of the compound electrode restrict each other and the mutual influence are much complex. The influences of all 4 parameters should be considered comprehensively, especially for the distance of two adjacent compound electrodes and the width of measurement electrode. Using only the overlay rate of electrodes is not a good way to deal with optimizing design of the compound electrode. This simulation conclusion is different from that of others made before. The simulation study of EIT electrode structure and parameter influence can be carried out according to this paper to determine the optimizing design of the electrode structure and its parameters. [ABSTRACT FROM AUTHOR]