---------------------------------- ---------------------------------- -------- Akhil Kallepalli -------- --- kallepalliakhil@icloud.com --- ---------------------------------- ---------------------------------- -----Monte Carlo simulations ----- -----run for SPIE Proceedings ---- -----titled "Quantification ------ -----and influence of skin ------- -----chromophores for remote ----- -----detection of anemic --------- -----conditions", presented at --- -----SPIE Photonics West 2020 ---- ---------------------------------- ---------------------------------- *************** Results shared with a CC-BY license (attribution to original work mandatory) *************** Abstract Current standards for diagnosing and monitoring anemia are relatively invasive. The superficial symptoms of this condition are due to an underlying deficiency of red blood cells (RBC) or erythrocytes, and hemoglobin in the blood. This results in an inadequate supply of oxygen to the body’s tissues. For point-of-care diagnostic systems, remote determination of blood conditions will depend on an understanding of the interaction of light with hemoglobin. However, the skin acts as the first barrier for this detection. In this study, we pursue the possibility of detecting anemic conditions from the perfused blood in the dermis using optical models and Monte Carlo (MC) methods. The skin is composed of two primary layers, the epidermis and the dermis. The avascular epidermis absorbs light due to its primary chromophore, melanin. Subsequently, the absorption in the dermis layer is quantified by hematocrit and hemoglobin concentrations. Two-layer models of the human skin are set up and optical properties are assigned to these models. The optical variability across these models are defined by six melanin (epidermis) and two erythrocytes (dermis) concentrations. The twelve combinations of optical properties are assessed at six wavelengths of interest in the Virtual Tissue Simulator (VTS) environment. The chosen wavelengths range across the visible and near-infrared spectrum, which is a known and important diagnostic window for biological tissues. In this study, we explore the variability of light interactions for healthy and anemic blood conditions quantified in the dermis while accounting for variable melanin concentrations in the epidermis. *************** Project Description The research results were generated for two-layer optical models. The layers are modeled as semi-infinite slabs with characteristics of the layers' chromophores. The optical properties (refractive index, absorption coefficient, scattering coefficient and anisotropy factor) define the attenuation when photons interact with these layers. The epidermis is modeled with different volume fractions of melanin. The dermis modeled according to the absorption coefficient model (Eq. 11, Quantitative assessment of skin layers absorption and skin reflectance spectra simulation in the visible and near-infrared spectral regions, Meglinski and Matcher, 2002). The factors that are varied are hematocrit and the vol. frac. of RBCs in the blood. An assumption of a standard, average vol. frac. of Hemoglobin the RBCs is made. *************** Folder organisation \Healthy Blood Perfusion -- Results (.png) outputs of the simulations including all skin types (Fitzpatrick scale) and dermal perfusion modeled with healthy blood characteristics (hematocrit and vol. frac. of RBCs). \Anaemic Blood Perfusion -- Results (.png) outputs of the simulations including all skin types (Fitzpatrick scale) and dermal perfusion modeled with anaemic blood characteristics (hematocrit and vol. frac. of RBCs). \#0 Simulation Results (MCCL Output) -- These are the simulation results. The results can be visualised using the package/contents of the archive "MC_v4.8.0Beta" in folder "MCCL Files (VTS and MATLAB files)" *************** Acknowledgement to the Virtual Photonics Technology Initiative (https://virtualphotonics.org/) This work was made possible through open-source software resources offered by the Virtual Photonics Technology Initiative, at the Beckman Laser Institute, University of California, Irvine. *************** This research is presented in SPIE Photonics West 2020 (February 2020) with the article titled: Quantification and influence of skin chromophores for remote detection of anemic conditions *************** Important Links Virtual Photonics Technology Initiative: https://virtualphotonics.org/ Virtual Technology Software (VTS) Documentation: https://virtualphotonics.org/documentation Virtual Photonics Repo: https://github.com/VirtualPhotonics Monte Carlo Command Line (MCCL) implementation: https://github.com/VirtualPhotonics/VTS/wiki/MCCL-Getting-Started All the information necessary to understand the the infiles, input, analysis, results generation are presented in the Git repository. The projects are regularly updated with new features/modalities.