Towards magnetic detection electrical impedance tomography: data acquisition and image reconstruction of current density in phantoms and in vivo.
The objective of magnetic detection electrical impedance tomography (MD-EIT) is to reconstruct in vivo images of conductivity from magnetic field measurements taken around the body. MD-EIT is performed by applying an alternating current, at one of a range of frequencies, to a conducting object through a pair of electrodes fixed to the surface of the object. Magnetic field measurements recorded by search coils at a number of positions around the object are used to determine the current distribution that is generating the magnetic field. From this distribution, a conductivity map of a cross-section of the object can be reconstructed. This paper describes the development of an MD-EIT data acquisition system and discusses the related image reconstruction issues. The ill-conditioned nature of the inverse problem is examined and a number of image reconstruction methods are compared. The technical feasibility of MD-EIT data collection and image reconstruction is demonstrated with example images of current density from both phantom and human data.
Ireland
R H
RH
Department of Medical Physics and Clinical Engineering, Royal Hallamshire Hospital, The University of Sheffield, S10 2JF, UK. r.ireland@sheffield.ac.uk
Tozer
J C
JC
Barker
A T
AT
Barber
D C
DC
D000465:Algorithms; D017097:Electric Impedance; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D016247:Information Storage and Retrieval / Q000379:methods; D008280:Magnetics / Q000295:instrumentation; D012984:Software; D013909:Thorax / Q000033:anatomy & histology* / Q000502:physiology*; D014054:Tomography / Q000379:methods*