Title :
Performance of the Sheffield Mk3A multi-frequency system for electrical impedance tomography
Author :
Wang, W. ; Brown, B.H. ; Barber, D.C.
Author_Institution :
Dept. of Med. Phys. & Clinical Eng., Sheffield Univ., UK
Abstract :
The Mk3A is a prototype of the Sheffield Mk3 system for the collection of transfer impedance data sets for Electrical Impedance Tomography. It uses 16 electrodes with a constant current drive and wide-band, high impedance voltage measurement on alternate-adjacent pairs of electrodes in the frequency range 9.6 kHz to 1.2 MHz. Triaxial input cables are used with the inner screen bootstrapped in order to maintain a high input impedance and minimise interaction between cables. The amplified multi-frequency signals are demodulated by analogue demodulators before multi-frequency calibration and image reconstruction. Dynamic, frequency and parametric images are reconstructed using a modified Sheffield Mk2 algorithm, which is a non-iterative, filtered back-projection algorithm
Keywords :
biomedical electronics; calibration; computerised tomography; demodulation; electric impedance imaging; electrodes; image reconstruction; medical image processing; 16-electrode system; 9.6 kHz to 1.2 MHz; Sheffield Mk3A multifrequency system; analogue demodulators; constant current drive; dynamic images; electrical impedance tomography; frequency images; image reconstruction; modified Sheffield Mk2 algorithm; multifrequency calibration; noniterative filtered backprojection algorithm; parametric images; performance; tissue impedance models; triaxial input cables; wide-band high impedance voltage measurement;
Conference_Titel :
Innovations in Instrumentation for Electrical Tomography, IEE Colloquium on
Conference_Location :
London
DOI :
10.1049/ic:19950645
