Determining the optical properties of blood using He-Ne laser and double integrating sphere set-up

Abstract

The behaviour of light interaction with biological tissue is determined by micro-optical parameters: refractive index (n), absorption coefficient (μa), scattering coefficient (μs), and anisotropy (g). The goal of this study is to measure the optical properties of normal whole blood using He-Ne laser (wavelength 632.8 nm). The refractive index is measured using the traveller microscope. The integrating sphere method is used to measure the macro-optical parameters: total diffusive reflectance, transmittance, and collimated transmittance at wavelength 632.8 nm. The macro-optical parameters are fed to Inverse Adding Doubling (IAD) theoretical technique, to estimate the micro-optical parameters (μs, μa, g). An alternative practical method is used to measure the g value based on utilising the goniometric table. The study reveals that the refractive index (n) equals 1.395±0.0547, absorption coefficient (μa) equals 2.37 mm-1, scattering coefficient (μs) equals 55.69 mm-1, and anisotropy (g) equals 0.82. In conclusion, these findings approved, in general, the applicability of the suggested experimental set up. The set up depend on using three devices: the integrating sphere method to estimate (μs, μa, g), traveller microscope (n) and goniometer (g).