Scattering signal extraction using quantitative phase imaging technique

Abstract

Flow cytometry, a technique for diagnostic and clinical analysis based on scattering signal analysis, is extensively used in medical applications. Although there is a close relationship between the intensity of distant scattering and the electric field at the image plane, this connection has not been studied in the context of flow cytometry. This thesis explores the relationship between scattering signals measured in flow cytometry and quantitative phase imaging. It demonstrates angle-resolved light scattering (ARLS), which is estimated using Fourier transform light scattering. This research employs off-axis holography to retrieve phase and amplitude from intensity raw images. By transforming the holography image into Fourier space, angle-dependent scattering signals. We successfully extract forward and side scattering signals from ARLS, allowing for the clear differentiation of bead types in the forward scatter (FSC) and side scatter (SSC) plots. We confirmed that the extraction of forward and side scatter signals from white blood cells showed a similar trend to that seen in conventional flow cytometry analysis. Additionally, it was demonstrated that using intermediate scatter signals around $45^\circ$ can more effectively differentiate white blood cells. The proposed method bridges the gap between flow cytometry data and quantitative phase imaging. It repurposes existing holographic images for scattering information, contributing to a deeper understanding of flow cytometry by providing insight into the relationship between light scattering and imaging.