title: Singular value decomposition based computationally efficient algorithm for rapid dynamic near-infrared diffuse optical tomography.
abstract: OBJECTIVE
  A computationally efficient algorithm (linear iterative type) based on singular value decomposition (SVD) of the Jacobian has been developed that can be used in rapid dynamic near-infrared (NIR) diffuse optical tomography.
  
  
  METHODS
  Numerical and experimental studies have been conducted to prove the computational efficacy of this SVD-based algorithm over conventional optical image reconstruction algorithms.
  
  
  RESULTS
  These studies indicate that the performance of linear iterative algorithms in terms of contrast recovery (quantitation of optical images) is better compared to nonlinear iterative (conventional) algorithms, provided the initial guess is close to the actual solution. The nonlinear algorithms can provide better quality images compared to the linear iterative type algorithms. Moreover, the analytical and numerical equivalence of the SVD-based algorithm to linear iterative algorithms was also established as a part of this work. It is also demonstrated that the SVD-based image reconstruction typically requires O(NN2) operations per iteration, as contrasted with linear and nonlinear iterative methods that, respectively, require O(NN3) and O(NN6) operations, with "NN" being the number of unknown parameters in the optical image reconstruction procedure.
  
  
  CONCLUSIONS
  This SVD-based computationally efficient algorithm can make the integration of image reconstruction procedure with the data acquisition feasible, in turn making the rapid dynamic NIR tomography viable in the clinic to continuously monitor hemodynamic changes in the tissue pathophysiology.
authors.affiliation: Department of Instrumentation, Indian Institute of Science, Bangalore 560 012, India.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Gupta
authors.forename: Phaneendra K
authors.initials: PK
authors.lastname: Yalavarthy
authors.forename: Debasish
authors.initials: D
authors.lastname: Roy
authors.forename: Daqing
authors.initials: D
authors.lastname: Piao
authors.forename: Ram M
authors.initials: RM
authors.lastname: Vasu
mesh_terms: D000465:Algorithms; D005240:Feasibility Studies; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007259:Infrared Rays; D013997:Time Factors; D041622:Tomography, Optical / Q000379:methods*