A phantom for electrical impedance tomography.

A method has been developed for constructing phantoms for electrical impedance tomography (EIT). A mesh of resistors is soldered to pins in a matrix board and forms a physical realisation of a finite element numerical model. To simulate different body tissues, changes in the apparent electrical conductivity and permittivity can be introduced at a particular location within the phantom by shunting the resistors in the mesh with additional resistors and capacitors. The phantom was used to test an EIT system employing phase-sensitive detection to separate the real and imaginary parts of the peripheral electric potentials. From the measurements images of conductivity and permittivity were reconstructed using an algorithm developed recently. The phantom has good mechanical strength and is electrically stable. The design could easily be reproduced and distributed to other centres developing similar EIT systems to enable testing on a common basis.