Analysis for nonlinear inversion technique developed to estimate depth-distribution of absorption by spatially resolved backscattering measurement

Kazuhiro Nishida, Takeshi Namita, Yuji Kato, Koichi Shimizu

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have proposed a new nonlinear inversion technique to estimate the spatial distribution of the absorption coefficient (μa) in the depth direction of a turbid medium by spatially resolved backscattering measurement. With this technique, we can obtain cross-sectional image of μa as deep as the backscattered light traveled even when the transmitted light through the medium cannot be detected. In this technique, the depth distribution of absorption coefficient is determined by iterative calculation using the spatial path-length distribution (SPD) of traveled photons as a function of source-detector distance. In this calculation, the variance of path-length of many photons in each layer is also required. The SPD and the variance of path-length are obtained by Monte Carlo simulation using a known reduced scattering coefficient (μs€™). Therefore, we need to know the μs€™ of the turbid medium beforehand. We have shown in computer simulation that this technique works well when the μs€™ is the typical values of mammalian body tissue, or 1.0 /mm. In this study, the accuracy of the μa estimation was analyzed and its dependence on the μs€™ was clarified quantitatively in various situations expected in practice. 10% deviations in μs€™ resulted in about 30% error in μa estimation, in average. This suggested that the measurement or the appropriate estimation of μs€™ is required to utilize the proposed technique effectively. Through this analysis, the effectiveness and the limitation of the newly proposed technique were clarified, and the problems to be solved were identified.

Original languageEnglish
Title of host publicationOptical Tomography and Spectroscopy of Tissue XI
PublisherSPIE
Volume9319
ISBN (Electronic)9781628414097
DOIs
Publication statusPublished - 2015
Externally publishedYes
EventOptical Tomography and Spectroscopy of Tissue XI - San Francisco, United States
Duration: 2015 Feb 92015 Feb 11

Other

OtherOptical Tomography and Spectroscopy of Tissue XI
CountryUnited States
CitySan Francisco
Period15/2/915/2/11

Fingerprint

Backscattering
Photons
backscattering
inversions
Light
estimates
Computer Simulation
absorptivity
Spatial distribution
Light sources
scattering coefficients
photons
Scattering
Tissue
Detectors
spatial distribution
computerized simulation
Computer simulation
deviation
detectors

Keywords

  • Absorption coefficient
  • Backscattering
  • Biomedical optics
  • CT imaging
  • Nonlinear inversion technique
  • Reduced scattering coefficient
  • Space-resolved measurement

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Radiology Nuclear Medicine and imaging

Cite this

Analysis for nonlinear inversion technique developed to estimate depth-distribution of absorption by spatially resolved backscattering measurement. / Nishida, Kazuhiro; Namita, Takeshi; Kato, Yuji; Shimizu, Koichi.

Optical Tomography and Spectroscopy of Tissue XI. Vol. 9319 SPIE, 2015. 93191X.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Nishida, K, Namita, T, Kato, Y & Shimizu, K 2015, Analysis for nonlinear inversion technique developed to estimate depth-distribution of absorption by spatially resolved backscattering measurement. in Optical Tomography and Spectroscopy of Tissue XI. vol. 9319, 93191X, SPIE, Optical Tomography and Spectroscopy of Tissue XI, San Francisco, United States, 15/2/9. https://doi.org/10.1117/12.2078168
Nishida, Kazuhiro ; Namita, Takeshi ; Kato, Yuji ; Shimizu, Koichi. / Analysis for nonlinear inversion technique developed to estimate depth-distribution of absorption by spatially resolved backscattering measurement. Optical Tomography and Spectroscopy of Tissue XI. Vol. 9319 SPIE, 2015.
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N2 - We have proposed a new nonlinear inversion technique to estimate the spatial distribution of the absorption coefficient (μa) in the depth direction of a turbid medium by spatially resolved backscattering measurement. With this technique, we can obtain cross-sectional image of μa as deep as the backscattered light traveled even when the transmitted light through the medium cannot be detected. In this technique, the depth distribution of absorption coefficient is determined by iterative calculation using the spatial path-length distribution (SPD) of traveled photons as a function of source-detector distance. In this calculation, the variance of path-length of many photons in each layer is also required. The SPD and the variance of path-length are obtained by Monte Carlo simulation using a known reduced scattering coefficient (μs€™). Therefore, we need to know the μs€™ of the turbid medium beforehand. We have shown in computer simulation that this technique works well when the μs€™ is the typical values of mammalian body tissue, or 1.0 /mm. In this study, the accuracy of the μa estimation was analyzed and its dependence on the μs€™ was clarified quantitatively in various situations expected in practice. 10% deviations in μs€™ resulted in about 30% error in μa estimation, in average. This suggested that the measurement or the appropriate estimation of μs€™ is required to utilize the proposed technique effectively. Through this analysis, the effectiveness and the limitation of the newly proposed technique were clarified, and the problems to be solved were identified.

AB - We have proposed a new nonlinear inversion technique to estimate the spatial distribution of the absorption coefficient (μa) in the depth direction of a turbid medium by spatially resolved backscattering measurement. With this technique, we can obtain cross-sectional image of μa as deep as the backscattered light traveled even when the transmitted light through the medium cannot be detected. In this technique, the depth distribution of absorption coefficient is determined by iterative calculation using the spatial path-length distribution (SPD) of traveled photons as a function of source-detector distance. In this calculation, the variance of path-length of many photons in each layer is also required. The SPD and the variance of path-length are obtained by Monte Carlo simulation using a known reduced scattering coefficient (μs€™). Therefore, we need to know the μs€™ of the turbid medium beforehand. We have shown in computer simulation that this technique works well when the μs€™ is the typical values of mammalian body tissue, or 1.0 /mm. In this study, the accuracy of the μa estimation was analyzed and its dependence on the μs€™ was clarified quantitatively in various situations expected in practice. 10% deviations in μs€™ resulted in about 30% error in μa estimation, in average. This suggested that the measurement or the appropriate estimation of μs€™ is required to utilize the proposed technique effectively. Through this analysis, the effectiveness and the limitation of the newly proposed technique were clarified, and the problems to be solved were identified.

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