Most EIT machines operate at high frequencies above 10 kHz. Biological systems demonstrate dispersions of electrical impedance characteristics at very low frequencies below 2 kHz due to the presence of membrane surrounding the cells and diffusion polarization effects. This book elaborate the feasibility of the use of low frequencies in a range of 1 Hz to 4.5 kHz in EIT. A frequency of 78 kHz normally used in EIT was used as a comparison. The impedance measurements employed a four-terminal method using an ultra low frequency impedance spectrometer and used conducting and insulating material as...