title: A comparison study of linear reconstruction techniques for diffuse optical tomographic imaging of absorption coefficient.
abstract: We compare, through simulations, the performance of four linear algorithms for diffuse optical tomographic reconstruction of the three-dimensional distribution of absorption coefficient within a highly scattering medium using the diffuse photon density wave approximation. The simulation geometry consisted of a coplanar array of sources and detectors at the boundary of a half-space medium. The forward solution matrix is both underdetermined, because we estimate many more absorption coefficient voxels than we have measurements, and ill-conditioned, due to the ill-posedness of the inverse problem. We compare two algebraic techniques, ART and SIRT, and two subspace techniques, the truncated SVD and CG algorithms. We compare three-dimensional reconstructions with two-dimensional reconstructions which assume all inhomogeneities are confined to a known horizontal slab, and we consider two 'object-based' error metrics in addition to mean square reconstruction error. We include a comparison using simulated data generated using a different FDFD method with the same inversion algorithms to indicate how our conclusions are affected in a somewhat more realistic scenario. Our results show that the subspace techniques are superior to the algebraic techniques in localization of inhomogeneities and estimation of their amplitude, that two-dimensional reconstructions are sensitive to underestimation of the object depth, and that an error measure based on a location parameter can be a useful complement to mean squared error.
authors.affiliation: CenSISS, CDSP Center, Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Gaudette
authors.forename: D H
authors.initials: DH
authors.lastname: Brooks
authors.forename: C A
authors.initials: CA
authors.lastname: DiMarzio
authors.forename: M E
authors.initials: ME
authors.lastname: Kilmer
authors.forename: E L
authors.initials: EL
authors.lastname: Miller
authors.forename: T
authors.initials: T
authors.lastname: Gaudette
authors.forename: D A
authors.initials: DA
authors.lastname: Boas
mesh_terms: D000465:Algorithms; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008962:Models, Theoretical; D014057:Tomography, X-Ray Computed / Q000379:methods*