In this paper, we present a Born-type approximation method for bioluminescence tomography (BLT), which is to reconstruct an internal bioluminescent source from the measured bioluminescent signal on the external surface of a small animal. Based on the diffusion approximation for the photon propagation in biological tissue, this BLT method utilizes the Green function to establish a linear relationship between the measured bioluminescent signal and the internal bioluminescent source distribution. The Green function can be modified to describe a heterogeneous medium with an arbitrary boundary using the Born approximation. The BLT reconstruction is formulated in a linear least-squares optimization framework with simple bounds constraint. The performance of this method is evaluated in numerical simulation and phantom experiments.
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http://dx.doi.org/10.1118/1.2168293 | DOI Listing |
Med Phys
March 2006
Bioluminescence Tomography Laboratory, Department of Radiology, University of Iowa, Iowa City, Iowa 52242, USA.
In this paper, we present a Born-type approximation method for bioluminescence tomography (BLT), which is to reconstruct an internal bioluminescent source from the measured bioluminescent signal on the external surface of a small animal. Based on the diffusion approximation for the photon propagation in biological tissue, this BLT method utilizes the Green function to establish a linear relationship between the measured bioluminescent signal and the internal bioluminescent source distribution. The Green function can be modified to describe a heterogeneous medium with an arbitrary boundary using the Born approximation.
View Article and Find Full Text PDFAppl Opt
April 2004
Commonwealth Scientific and Industrial Research Organisation-Manufacturing and Infrastructure Technology, PB 33, Clayton South, VIC 3169, Australia.
The first Born and Rytov approximations of scattering theory are introduced in their less familiar near-field versions. Two algorithms for phase retrieval based on these approximations are then described. It is shown theoretically and by numerical simulations that, despite the differences in their formulation, the two algorithms deliver fairly similar results when used for optical phase retrieval in the near and intermediate fields.
View Article and Find Full Text PDFScattering of guided modes from an abruptly terminated waveguide is analyzed through an integral-equation formulation. First the boundary-value problem for a plane-stratified waveguide with arbitrary profile is reduced to a canonical system of surface integral equations. A Born-type iterative procedure is then employed to obtain a tractable solution of the scattering field at the termination.
View Article and Find Full Text PDFThe use of gaussian-type orbitals (GTO) as basis sets of electronic wave functions of molecules for calculating electron-collision excitation cross sections is discussed. A test calculation of the electron excitation cross section of the 2p state of atomic hydrogen at 60-1000 eV in which the hydrogenic wave functions were expressed as linear combinations of GTO indicates that an expansion of the is wave function by six GTO's and the 2p by four GTO's gives quite accurate results. Methods for evaluating the multicenter integrals which appear in the expressions of electron-excitation cross section (by the Born-type approximation) of diatomic molecules are described.
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