title: Quantitative reconstruction of refractive index distribution and imaging of glucose concentration by using diffusing light.
abstract: We show that a two-step reconstruction method can be adapted to improve the quantitative accuracy of the refractive index reconstruction in phase-contrast diffuse optical tomography (PCDOT). We also describe the possibility of imaging tissue glucose concentration with PCDOT. In this two-step method, we first use our existing finite-element reconstruction algorithm to recover the position and shape of a target. We then use the position and size of the target as a priori information to reconstruct a single value of the refractive index within the target and background regions using a region reconstruction method. Due to the extremely low contrast available in the refractive index reconstruction, we incorporate a data normalization scheme into the two-step reconstruction to combat the associated low signal-to-noise ratio. Through a series of phantom experiments we find that this two-step reconstruction method can considerably improve the quantitative accuracy of the refractive index reconstruction. The results show that the relative error of the reconstructed refractive index is reduced from 20% to within 1.5%. We also demonstrate the possibility of PCDOT for recovering glucose concentration using these phantom experiments.
authors.affiliation: J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville 32611, USA. xliang@bme.ufl.edu
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Liang
authors.forename: Qizhi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Huabei
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000465:Algorithms; D015374:Biosensing Techniques / Q000379:methods*; D003198:Computer Simulation; D005947:Glucose / Q000032:analysis*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008027:Light; D008954:Models, Biological; D012031:Refractometry / Q000379:methods*; D012542:Scattering, Radiation
chemical_list: D005947:Glucose