CIBC:Documentation:SCIRun:Reference:BioPSE:BuildEITMatrix
From NCRR Biomedical Software Development, Engineering, and Dissemination Wiki
Contents |
BuildEITMatrix
Information
- Package: BioPSE
- Catagory: Forward
- Author(s): Saeed Babaeizadeh
- Status: Supported in latest version
- Version: 3.0
Description
Summary
The module solves a discretized model of Laplace's equation in a 3D volume conductor model using "surface method", given a particular type of boundary condition.
Detailed Description
The specific problem the authors had in mind was the forward problem of Electrical Impedance Tomography (EIT) which consists of calculating, for a given time instant, the potential distribution generated at the surface of a specified volume conductor due the presence of some current sources on the same surface (the module should work for other problems which fit the same physical description, but has only been tested for forward EIT.) In surface methods, the different volume conductor regions are assumed to have a constant and isotropic conductivity, and only the interfaces between the different regions are triangulated and represented in the numerical model. This module is based on a method developed in [i] and uses the "Transfer-Coefficient Approach" or "solid-angle method" developed by Barr et al. [ii], as extended to include torso inhomogeneities in [iii] and with an improved algorithm for computing the solid angles [iv].
[i] S. Babaeizadeh, D. H. Brooks, and D. Isaacson, "A 3-D Boundary Element Solution to the Forward Problem of Electrical Impedance Tomography, " Proceedings of the 26th Annual International Conference of the IEEE EMBS, pp. 960-963, 2004.
[ii] R.C. Barr, M. Ramsey, and M.S. Spach, "Relating epicardial to body surface potential distribution by means of transfer coefficients based on geometry measurement," IEEE Trans. Biomed. Eng., vol. BME-24, pp. 1-11, 1977.
[iii] P.C. Stanley, T.C. Pilkington, and M.N. Morrow., "The effects of thoracic inhomogeneities on the relationship between epicardial and torso potentials," IEEE Transactions on Biomedical Engineering, BME-33, pp.273-284, 1986.
[iv] J.A. De Munck, "Linear discretization of the volume conductor boundary integral equation using analytically integrated elements," IEEE Trans. Biomed. Eng., vol. 39, no. 9, 1992.
This module requires the triangulated surfaces of all the objects as inputs and creates the forward solution matrix as output. The geometric relationships of the surfaces are defined as described below, as are the boundary conditions to apply.
The number of input fields is one or two. The outermost surface is the surface on which Neumann boundary condition is given where the quantity of interest is the Dirichlet boundary condition which is to be calculated.
To define the geometric relationships of the various fields, for each of the input fields use a "SetProperty" module with `Property'=`Inside Conductivity' and `Value' = the numerical value of the internal conductivity of the corresponding homogeneous region.
The output is the forward solution matrix. This matrix can be multiplied to a Neumann boundary condition on the outermost surface; to result in the Dirichlet boundary condition on the same surface.
Frequently Asked Questions
Known Bugs
Recent Changes
Go back to Documentation:SCIRun:Reference:BioPSE
