Toggle Main Menu Toggle Search

Open Access padlockePrints

Spatially-resolved in-Vivo measurement system for estimating the optical properties of tissue in the wavelength range 1000-1700nm

Lookup NU author(s): Par Hjalmarsson, Dr Suresh Thennadil


Full text for this publication is not currently held within this repository. Alternative links are provided below where available.


For non-invasive estimation of optical properties (i.e. determination of the absorption and the reduced scattering coefficients) of turbid media such as tissue, spatially resolved diffuse reflectance spectroscopy is one of most used technique. So far this has only been done for wavelengths covered by CCD-detectors (about 350-1050nm). The NIR region beyond 1050nm i.e. the second and first overtone regions, has absorption peaks of interest e.g. for tissue the glucose peak at around 1250nm and 1600nm. Thus for non-invasive medical diagnostics applications, a spatially resolved measurement system capable of estimating optical properties in this region will be very useful. Until now optical properties of tissue in this region have only been estimated using in vitro methods e.g. using an integrating sphere set-up. In this paper we describe a spatially resolved system that will extend the region up to 1700nm by using a TE cooled 320x256 pixel InGaAS detector, a white light source and a probe that consists of 9x200micron fibres spanning 0.3 to 2.7mm from the source. Across the 320 pixels 680nm will be dispersed giving a resolution of 2.125nm/pixel and a resolving power of about 14nm. The system is validated using tissue-like phantoms. Since tissue has a high concentration of water which leads to high absorption after 950nm, the diffusion approximation cannot be used to extract the optical properties from the spatially resolved measurements. Instead, two techniques based around Monte Carlo simulations of diffuse reflectance profiles, to build a lookup table coupled with interpolation using splines or a third order polynomial, have been used to calculate the optical properties for different wavelengths. The performances of these techniques are compared. It was found that the spline fitting produced lower error for the wavelength region considered.

Publication metadata

Author(s): Hjalmarsson P, Thennadil SN

Editor(s): Schweitzer, D; Fitzmaurice, M

Publication type: Conference Proceedings (inc. Abstract)

Publication status: Published

Conference Name: Diagnostic Optical Spectroscopy in Biomedicine IV

Year of Conference: 2007

Pages: 62805

ISSN: 0277-786X (print) 1042-4687 (online)

Publisher: SPIE

Library holdings: Search Newcastle University Library for this item

Series Title: Proceedings of the International Society for Optical Engineering

ISBN: 9780819467720