title: Continuous Wave Spectroscopy with Diffusion Theory for Quantification of Optical Properties: Comparison Between Multi-distance and Multi-wavelength Data Fitting Methods.
abstract: Typically, continuous wave spectroscopy (CWS) can be used to accurately quantify biological tissue optical properties (μ a and μ s ') by employing the diffuse reflectance information acquired at multiple source-detector separations (multi-distance). On the other hand, sample optical properties can also be obtained by fitting multi-wavelength light reflectance acquired at a single source detector separation to the diffusion theory equation. To date, multi-wavelength and multi-distance methods have not yet been rigorously compared for their accuracy in quantification of the sample optical properties. In this investigation, we compared the accuracy of the two above-mentioned quantifying methods in the optical properties recovery. The liquid phantoms had μ a between 0.004 and 0.011 mm(-1) and μ s ' between 0.55 and 1.07 mm(-1) whose optical properties mimic the human breast. Multi-distance data and multi-wavelength data were fitted to the same diffusion equation for consistency. The difference between benchmark μ a and μ s ' and the fitted results, ΔError (ΔE) was used to evaluate the accuracy of the two methods. The results showed that either method yielded ΔE within 15-30 % when values were within certain limits to standard values applicable to μ s ' and μ a for human adipose tissue. Both methods showed no significant differences in ΔE values. Our results suggest that both multi-distance and multi-wavelength methods can yield similar reasonable optical properties in biological tissue with a proper calibration.
authors.affiliation: Institute of Computer and Communication Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yung-Chi
authors.initials: YC
authors.lastname: Lin
authors.affiliation: Department of Photonics, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Zhi-Fong
authors.initials: ZF
authors.lastname: Lin
authors.affiliation: Department of Radiology, Medical School of University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Shoko
authors.initials: S
authors.lastname: Nioka
authors.affiliation: Institute of Computer and Communication Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Li-Hsin
authors.initials: LH
authors.lastname: Chen
authors.affiliation: Department of Photonics, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Sheng-Hao
authors.initials: SH
authors.lastname: Tseng
authors.affiliation: Institute of Computer and Communication Engineering, National Cheng Kung University, Tainan, Taiwan. pcchung@ee.ncku.edu.tw.
authors.forename: Pau-Choo
authors.initials: PC
authors.lastname: Chung
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry*; D000465:Algorithms; D000814:Aniline Compounds / Q000737:chemistry; D002138:Calibration; D003198:Computer Simulation; D004058:Diffusion; D004655:Emulsions / Q000737:chemistry; D006801:Humans; D008962:Models, Theoretical; D009010:Monte Carlo Method; D055095:Optics and Photonics / Q000379:methods* / Q000592:standards; D019047:Phantoms, Imaging; D010743:Phospholipids / Q000737:chemistry; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013024:Soybean Oil / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods* / Q000592:standards
chemical_list: D000814:Aniline Compounds; D004655:Emulsions; D010743:Phospholipids; C545823:soybean oil, phospholipid emulsion; D013024:Soybean Oil; C002712:nigrosin
keywords: Curve fitting; Diffuse reflectance; Near-infrared spectroscopy; Optical property; Simulating phantom