title: Optical coherence tomography for blood glucose monitoring in vitro through spatial and temporal approaches.
abstract: As diabetes causes millions of deaths worldwide every year, new methods for blood glucose monitoring are in demand. Noninvasive approaches may increase patient adherence to treatment while reducing costs, and optical coherence tomography (OCT) may be a feasible alternative to current invasive diagnostics. This study presents two methods for blood sugar monitoring with OCT in vitro. The first, based on spatial statistics, exploits changes in the light total attenuation coefficient caused by different concentrations of glucose in the sample using a 930-nm commercial OCT system. The second, based on temporal analysis, calculates differences in the decorrelation time of the speckle pattern in the OCT signal due to blood viscosity variations with the addition of glucose with data acquired by a custom built Swept Source 1325-nm OCT system. Samples consisted of heparinized mouse blood, phosphate buffer saline, and glucose. Additionally, further samples were prepared by diluting mouse blood with isotonic saline solution to verify the effect of higher multiple scattering components on the ability of the methods to differentiate glucose levels. Our results suggest a direct relationship between glucose concentration and both decorrelation rate and attenuation coefficient, with our systems being able to detect changes of 65  mg/dL in glucose concentration.
authors.affiliation: Nuclear and Energy Research Institute, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, BrazilbUniversity of São Paulo, Postgraduate Program in Nuclear Technology, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, Brazil.
authors.forename: Lucas Ramos
authors.initials: LR
authors.lastname: De Pretto
authors.affiliation: Nuclear and Energy Research Institute, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, BrazilbUniversity of São Paulo, Postgraduate Program in Nuclear Technology, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, Brazil.
authors.forename: Tania Mateus
authors.initials: TM
authors.lastname: Yoshimura
authors.affiliation: Nuclear and Energy Research Institute, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, Brazil.
authors.forename: Martha Simões
authors.initials: MS
authors.lastname: Ribeiro
authors.affiliation: Nuclear and Energy Research Institute, Av. Professor Lineu Prestes, 2242, São Paulo, SP, 05508-000, Brazil.
authors.forename: Anderson
authors.initials: A
authors.lastname: Zanardi de Freitas
mesh_terms: D000818:Animals; D001774:Blood Chemical Analysis / Q000295:instrumentation* / Q000379:methods*; D001786:Blood Glucose / Q000032:analysis*; D003920:Diabetes Mellitus / Q000097:blood*; D006801:Humans; D051379:Mice; D015203:Reproducibility of Results; D041623:Tomography, Optical Coherence
chemical_list: D001786:Blood Glucose