title: A new geometric factor for in situ resistivity measurement using four slender cylindrical electrodes.
abstract: The four-electrode method is commonly used for in situ measurement of the electrical resistivity of biological tissues. In this paper, a new geometric factor between the resistivity and measured resistance using the four-electrode interface is derived in the prolate spheroidal coordinates and experimentally validated. Evaluation of the experimental results shows that the resistivities determined using both the derived geometric factor and a commercial conductivity meter are in close agreement even when the length of the immersed electrodes becomes long with respect to the inter-electrode spacing. The evaluation also shows the effect of the relative size of the sample volume when the limitation to semi-infinite volume begins to result in poor accuracy.
authors.affiliation: School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798. n030071@ntu.edu.sg
authors.forename: Chee-Earn
authors.initials: CE
authors.lastname: Chong
authors.forename: Yoke-Lin
authors.initials: YL
authors.lastname: Tan
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000295:instrumentation / Q000379:methods; D017097:Electric Impedance; D004566:Electrodes; D008954:Models, Biological; D010992:Plethysmography, Impedance / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity