The Determination of Absorption and Reduced Scattering Coefficients of Optical Phantoms Using a Frequency-Domain Multi-Distance Method in a Non-contact Manner

Abstract

A non-contact optical system has been designed to determine the absorption and reduced scattering coefficients of optical phantoms. The frequency-domain multi-distance method, which allows an estimation of optical properties in biological tissue uses the phase and intensity of radio frequency modulated light. The proposed design has been evaluated with optical phantoms. Estimated values for an absorption coefficient equal to 1 cm-1 are 0.795, 0.690, 0.670 and 0.613 cm-1 for wavelengths of 658 nm, 705 nm, 785 nm and 833 nm, respectively and for a reduced scattering coefficient equal to 22 cm-1, the estimated values are 19.876, 18.845, 17.134 and 17.927 cm-1. It has been concluded that this novel non-contact design can be used to determine the absorption and reduced scattering coefficients of optical phantoms. This system is the first step in medical equipment that may be used to measure absolute quantification of HbO, Hb, HbCO and HbMet concentrations in a contactless manner. Current oximeters with hemoglobin measurement capability require contact between the sensor and the skin. These oximeters have drawbacks when measuring child patients with asthma, bronchiolitis and bronchopneumonia. Currently it is not possible to assess oxygenation in open wounds. Therefore, it is worthwhile to develop a non-contact oximeter.

Keywords

• absorption
• biophotonics
• optical sensors
• optoelectronic devices
• spectroscopy