Scattering-independent glucose absorption measurement using a spectrally resolved reflectance setup with specialized variable source-detector separations.

Jin Liu,Jingying Jiang,Kexin Xu,Caigang Zhu

doi:10.1364/boe.9.005903

Abstract

We report a novel approach for the accurate measurement of glucose absorption in turbid media using a spectrally resolved reflectance setup. Our proposed reflectance setup with specialized variable source-detector separations enables scattering-independent absorption measurement, which is critical to in vivo long-term glucose concentration monitoring. Starting from the first-order approximation of the radiative transfer equation (RTE), we developed a scattering-independent glucose absorption measurement method and then evaluated this approach by Monte Carlo simulations as well as tissue-mimicking phantom studies in which glucose concentration was accurately measured. Our study demonstrates the potential of our proposed scattering-independent absorption measurement technique as an effective tool to quantify glucose levels in turbid media, which is an important step towards future in vivo long-term glucose concentration monitoring in human subjects.

Highlights

Near-infrared spectroscopy (NIRS) techniques have been explored extensively for biomedical applications in the past decade [1]
Starting from the first-order approximation of the radiative transfer equation (RTE) [33], we developed a novel equation to describe the relationship between the scattering independent source-detector separations and the tissue background optical properties
To demonstrate the proof-of-concept, we reported a reflectance setup with specialized variable source-detector separations to enable accurate glucose absorption measurement from a turbid medium

Summary

Introduction

Near-infrared spectroscopy (NIRS) techniques have been explored extensively for biomedical applications in the past decade [1]. Many analyzing techniques have been developed to reduce scattering effect and some of them achieved decent results as long as sufficient training data was used [19,20,21,22], while most of these techniques failed when they were used for in vivo long-term glucose monitoring [23,24] This is likely because tissue scattering is sensitive to body temperature and motion artifact et al [25]. Duadi et al [31] has taken an angularisobaric-points based approach to perform scattering insensitive reflectance measurements on cylindrical tissues like fingertip or earlobe with a goal of quantifying tissue blood content Their angular-based source-detector design will potentially improve the accuracy of vascular endpoints quantification using a pulse oximeter [32]. Our study demonstrates the great potential of our technique for scattering-independent glucose absorption measurement in turbid media, which is an important step towards future long-term in vivo glucose concentration monitoring in human subjects. It should be noted that the isobaric-points based techniques would generally be applicable to the characterization of other tissue components [35] in addition to glucose, other fields including milk purity characterization, juice purity characterization, and so on, as long as the specialized sourcedetector separations for a given turbid medium were found

Materials and methods

Monte Carlo simulations

Prediction model for glucose concentration estimation

Results

Discussion

Conclusion