Electrical impedance tomography method and electrode arrangement for use therein
First Claim
1. A method of determining electrical impedance tomography of a conductive volume (12) comprising the steps of selecting, in turn, each of a plurality of pairs of locations (S) upon a surface of the volume (12) and supplying a stimulation current to the surface by way of the selected pair of locations, and recording, for each selected pair, a resulting potential difference between at least one pair (R) of the remaining locations, and processing the recorded potential differences to plot electrical conductivity distribution within said volume, and, for a particular pair of locations stimulated, selecting from among the remaining locations, for recordal, the pair or pairs of locations which, if stimulated, would produce an electric field with vectors most closely aligned with the corresponding vectors of the electric field produced by stimulation of said particular pair of locations, and recording said potential difference at the said pair or pairs of locations so selected for recordal.
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Accused Products
Abstract
An electrode arrangement for an electrical impedance tomography system comprises a plurality of electrodes in an array mounted in a support medium for supporting the electrodes adjacent a surface of a volume the electrical conductivity distribution of which is to be measured, for example the thorax or another body part, a pipeline, the ground, and so on. The electrodes are disposed in two groups, the arrangement being such that, in use, one group will be closer to the surface than the other group, In operation, applying a known current to them. For each stimulated pair, a resulting potential difference will be recorded at the pair of the remaining electrodes which, if stimulated, would produce an electric field with vectors of the electric field produced by the stimulated pair of electrodes.
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Citations
53 Claims
- 1. A method of determining electrical impedance tomography of a conductive volume (12) comprising the steps of selecting, in turn, each of a plurality of pairs of locations (S) upon a surface of the volume (12) and supplying a stimulation current to the surface by way of the selected pair of locations, and recording, for each selected pair, a resulting potential difference between at least one pair (R) of the remaining locations, and processing the recorded potential differences to plot electrical conductivity distribution within said volume, and, for a particular pair of locations stimulated, selecting from among the remaining locations, for recordal, the pair or pairs of locations which, if stimulated, would produce an electric field with vectors most closely aligned with the corresponding vectors of the electric field produced by stimulation of said particular pair of locations, and recording said potential difference at the said pair or pairs of locations so selected for recordal.
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11. An electrode arrangement for an electrical impedance tomography system comprising a first group of electrodes (R1-R16) and a second group of electrodes (S1-S16) and support means (24,26,28,30) for supporting the electrodes adjacent a surface of a volume (12′
- ) the electrical impedance of which is to be mapped by the system, wherein the first group of electrodes (R1-R16) is closer than the second group of electrodes (S1-S16) to a part of the support means which, in use, will be adjacent said surface.
- View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. An electrode arrangement for an electrical impedance tomography system comprising a plurality of electrodes (S1-S16, R1-R16) in an array mounted in a support (24,26,28,30) for supporting the electrodes adjacent a surface of a volume (12′
- ) to be imaged, wherein the support comprises a plurality of low conductivity sections (281-2816) alternating with a plurality of high conductivity sections (321-3216) so that its conductivity in a direction that, in use, is normal to the surface is significantly greater than its conductivity in a transverse direction, and the electrodes (R1-R16, S1-S16) are disposed in the high conductivity sections (321-3216), respectively, so as to be spaced, in use, from said surface.
- View Dependent Claims (37)
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38. An electrode arrangement for an electrical impedance tomography system comprising an array of electrodes (S1-S16, R1-R16) fixed spatially relative to each other in a rigid support (24,26,28,30), and an interface medium (36) for interfacing the rigid support to a surface of a volume (12′
- ) the conductivity distribution of which is to be measured, the interface medium being conductive so as to connect the electrodes electrically to the surface and pliable so as to conform to variations in relief of the surface.
- View Dependent Claims (39, 40)
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41. An electrical impedance tomograph comprising a first group of electrodes (R1-R16) and a second group of electrodes (S1-S16) and support means (24,26,28,30) for supporting the electrodes adjacent a surface of a volume (12′
- ) the electrical impedance of which is to be mapped by the system, wherein the first group of electrodes (R1-R16) is closer than the second group of electrodes (S1-S16) to a part of the support means which, in use, will be adjacent said surface, and further comprising means (16,18,20) for stimulating, sequentially, pairs of electrodes (S1-S16) and, for each pair stimulated, measuring corresponding potential differences between a pair or pairs of the remaining electrodes, and processing the measured potentials to map electrical conductivity distribution of a volume (12′
). - View Dependent Claims (42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
- ) the electrical impedance of which is to be mapped by the system, wherein the first group of electrodes (R1-R16) is closer than the second group of electrodes (S1-S16) to a part of the support means which, in use, will be adjacent said surface, and further comprising means (16,18,20) for stimulating, sequentially, pairs of electrodes (S1-S16) and, for each pair stimulated, measuring corresponding potential differences between a pair or pairs of the remaining electrodes, and processing the measured potentials to map electrical conductivity distribution of a volume (12′
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53. An electrical impedance tomograph for use in a method of determining electrical impedance tomography of a conductive volume (12) by selecting, in turn, each of a plurality of pairs of locations (S) upon a surface of the volume (12) and supplying a stimulation current to the surface by way of the selected pair of locations, and recording, for each selected pair, a resulting potential difference between at least one pair (R) of the remaining locations, and processing the recorded potential differences to plot electrical conductivity distribution within said volume comprising:
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(i) a plurality of electrodes (S1-S16, R1-R16) for disposing upon or adjacent said surface, each at a respective one of said plurality of locations;
(ii) means (16) for selecting each pair (S1,S2;
S2,S3, . . . S15,S16) of electrodes in turn and applying a stimulation current thereto and, for each particular pair of locations stimulated, the pair or pairs of locations which, if stimulated, would produce an electric field with vectors most closely aligned with the corresponding vectors of the electric field produced by stimulation of said particular pair of locations; and
recording the potential difference between each pair of electrodes selected for recordal; and
(iii) means (18) for processing the recorded potential differences to determine the electrical impedance tomography for the volume.
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Specification