Electric Current Computed Tomography and Eigenvalues

Abstract

In electric current computed tomography, patterns of currents or voltages are applied to electrodes on the surface of a body and the resulting voltages or currents are measured. A reconstruction and display of an approximation to the impedance inside the body is then made based on these external measurements. It is shown how the problems of choosing current patterns, electrode size and number can be studied in terms of the spectral properties of certain pseudodifferential operators. The proofs given here are simpler and more general than those in [ IEEE Trans. Medical Imaging, 5 (1986), pp. 91–95] and [Clin. Phys. Physiol. Meas. Suppl. A, (1987), pp. 39–46].