Induced current electrical impedance tomography system: experimental results and numerical simulations.
In electrical impedance tomography (EIT), measurements of developed surface potentials due to applied currents are used for the reconstruction of the conductivity distribution. Practical implementation of EIT systems is known to be problematic due to the high sensitivity to noise of such systems, leading to a poor imaging quality. In the present study, the performance of an induced current EIT (ICEIT) system, where eddy current is applied using magnetic induction, was studied by comparing the voltage measurements to simulated data, and examining the imaging quality with respect to simulated reconstructions for several phantom configurations. A 3-coil, 32-electrode ICEIT system was built, and an iterative modified Newton-Raphson algorithm was developed for the solution of the inverse problem. The RMS norm between the simulated and the experimental voltages was found to be 0.08 +/- 0.05 mV (<3%). Two regularization methods were implemented and compared: the Marquardt regularization and the Laplacian regularization (a bounded second-derivative regularization). While the Laplacian regularization method was found to be preferred for simulated data, it resulted in distinctive spatial artifacts for measured data. The experimental reconstructed images were found to be indicative of the angular positioning of the conductivity perturbations, though the radial sensitivity was low, especially when using the Marquardt regularization method.
Zlochiver
Sharon
S
Department of Biomedical Engineering, Tel-Aviv University, Tel-Aviv, Israel.
Radai
M Michal
MM
Abboud
Shimon
S
Rosenfeld
Moshe
M
Dong
Xiu-Zhen
XZ
Liu
Rui-Gang
RG
You
Fu-Sheng
FS
Xiang
Hai-Yan
HY
Shi
Xue-Tao
XT
D000465:Algorithms; D003198:Computer Simulation; D017097:Electric Impedance; D008954:Models, Biological; D015203:Reproducibility of Results; D014054:Tomography / Q000379:methods*