Reconstruction of angle-resolved backscattering through a multimode fiber for cell nuclei and particle size determination

Haoran Zhang,Silvia Ceballos,Kengyeh K Chu,Adam Wax,Zachary A Steelman

doi:10.1063/5.0011500

Abstract

We demonstrate reconstruction of angle-resolved optical backscattering after transmission through a multimode fiber. Angle-resolved backscattering is an important tool for particle sizing, and has been developed as a diagnostic modality for detecting epithelial precancer. In this work, we fully characterized the transfer function of a multimode fiber using a plane-wave illumination basis across two dimensions. Once characterized, angle-resolved scattering information which has been scrambled by multimodal propagation can be easily and accurately reconstructed. Our technique was validated using a Mie theory-based inverse light scattering analysis (ILSA) algorithm on polystyrene microsphere phantoms of known sizes. To demonstrate the clinical potential of this approach, nuclear morphology was determined from the reconstructed angular backscattering from MCF-10A human mammary epithelial cell samples and validated against quantitative image analysis (QIA) of fluorescence microscopy images.

Highlights

Endoscopic imaging has become a widely researched field due to its ability to visualize inaccessible structures1–5 including the esophagus, colon, and cervix
The angular range from 0○ to 16.2○ collected by the multimode fiber is sufficient to accurately measure the size of the scatterer, and satisfies the required resolution for diagnostic modalities such as angle-resolved low-coherence interferometry (a/LCI).36
The typical sampling period of fiber bundles used for clinical endoscopy would be ∼0.5○,38 which is limited by the distance between two adjacent core elements in the fiber bundle

Summary

Introduction

Endoscopic imaging has become a widely researched field due to its ability to visualize inaccessible structures including the esophagus, colon, and cervix. An imaging fiber bundle is used as a flexible image conduit, where each single-core element at the distal face maps light to a corresponding location on the proximal side of the bundle to relay intensity-based images while maintaining spatial orientation. Because fiber bundles have a sparse field of single-mode cores interspersed among a surfeit of space-occupying cladding, commercially available fiber bundles usually have relatively low OAR (poor light throughput). An alternative approach is to relay the image using a single multimode fiber using the multiple modes supported by the fiber to encode spatial image data. Imaging through a multimode fiber has a clear advantage over transmitting images through a fiber bundle, including improved resolution, throughput, simplicity, cost, and the ability to access more spatially constrained applications such as brain imaging. Optical transmission through a multimode fiber constitutes a linear system for which any input function can be reconstructed from its corresponding output function, assuming complete knowledge of the system’s transfer function

Methods

Results

Discussion

Conclusion