Parallel inverseproblem solver for timedomain optical tomography with perfect parallel scaling
Abstract
This paper presents an efficient parallel radiative transferbased inverseproblem solver for timedomain optical tomography. The radiative transfer equation provides a physically accurate model for the transport of photons in biological tissue, but the high computational cost associated with its solution has hindered its use in timedomain opticaltomography and other areas. In this paper this problem is tackled by means of a number of computational and modeling innovations, including (1) A spatial paralleldecomposition strategy with perfect parallel scaling for the forward and inverse problems of optical tomography on parallel computer systems; and, (2) A Multiple Staggered Source method (MSS) that solves the inverse transport problem at a computational cost that is independent of the number of sources employed, and which significantly accelerates the reconstruction of the optical parameters: a sixfold MSS acceleration factor is demonstrated in this paper. Finally, this contribution presents (3) An intuitive derivation of the adjointbased formulation for evaluation of functional gradients, including the highlyrelevant general Fresnel boundary conditionsthus, in particular, generalizing results previously available for vacuum boundary conditions. Solutions of large and realistic 2D inverse problems are presented in this paper, which were produced on a 256core computer system. The combined parallel/MSS acceleration approach reduced the required computing times by several orders of magnitude, from months to a few hours.
 Publication:

Journal of Quantitative Spectroscopy and Radiative Transfer
 Pub Date:
 November 2022
 DOI:
 10.1016/j.jqsrt.2022.108300
 arXiv:
 arXiv:2202.09421
 Bibcode:
 2022JQSRT.29008300G
 Keywords:

 Physics  Medical Physics;
 Physics  Computational Physics
 EPrint:
 doi:10.1016/j.jqsrt.2022.108300