Visualization of backscattering photon distribution with beam-offset OCT

Abstract

To image the underlying structures of a scattering medium, raster scanning imaging technologies capture least scattered photons (LSPs) and reject multiple scattered photons (MSPs) in backscattered photons. However, MSPs can still squeeze into the images, resulting in limited imaging depth, degraded contrast, and significantly reduced lateral resolution. Great efforts have been made to understand how MSPs affect imaging performance through modeling, but how the backscattered photons are distributed in a scattering medium during imaging remains a conceived picture base on simulations. Here, we demonstrate a method of reconstructing BSPP using beam-offset optical coherence tomography (OCT), where OCT images are acquired at offset positions from the illumination beam. By separating LSPs and MSPs, we can quantify imaging depth, contrast, and lateral resolution and access the depth-resolved modulated transfer function (MTF). This approach presents great opportunities for better retrieving tissue optical properties, correctly interpreting images, or directly using MTF as the feedback for adaptive optical imaging.