Optical Simulation Study for Non-Invasive Jaundice Application: Effect of Bilirubin, Melanosome, LED Radial Width Distribution and Optode Distance

Abstract

One of the promising diagnosis devices is the non-invasive bilirubin detection for estimating newborn jaundice. From the light interaction through tissue perspective, less attention has been given to the effect of LED radial width distribution at different melanosome content and bilirubin concentrations. Besides, different optode (emitter-detector) spacing can affect the light measured at the detector. This paper aims to investigate the effects of three LED radial width distributions (30°, 40° and 60°) on three types of skin pigmentation (light-skinned Caucasians, well-tanned Caucasians and Mediterranean, and dark-skinned pigmented Africans) based on hyperbilirubinemia and excessive hyperbilirubinemia conditions by using MCmatlab to simulate a 3D cuboid shape of neonatal forehead tissue layers. To mimic the tissues model, optical properties such as absorption coefficient (μ_a), reduced scattering coefficient (〖'μ〗_s), and scattering anisotropy (g) were applied in every layer. Wavelength 470 nm was chosen since it is the most responsive wavelength at bilirubin’s absorption spectra. Two optode spacing (0.7 cm and 2 cm) were used to demonstrate the effect of LED radial width. Main findings revealed that for all three types of skin, 30° LED radial width distribution resulted different trends in 0.7 cm and 2 cm of optode spacing. At 0.7 cm, a higher percentage of incident light was collected at the detector, whereas diffuse reflectance was lower. However, at a 2cm distance, both diffuse reflectance and the percentage of incident light collected on the detector were lower. These measured outcomes in diffuse reflectance on light skin were increased by six times, and the incident light collected was one time larger than on tanned and dark skin, as light skin colour absorbs less light and therefore gives a better reflection. Different optode spacing will be investigated for future studies as this information can serve as valuable input when designing optical hardware for non-invasive jaundice detection.