Febrile neutropenia (FN) is a common cause of hospitalization for cancer patients undergoing chemotherapy treatment. To screen for FN, patients require invasive blood draws and complete blood cell counts, which increases risk of nosocomial infection while in an immunocompromised state. There is a pressing clinical need for non-invasive, point-of-care technology to frequently screen for FN, which, if detected early, can be prophylactically managed. A promising approach to address this need is capillaroscopy, through which blood cells are imaged in capillaries non-invasively. Visualization of shadows caused by absorption of individual red blood cells is currently achievable, and correlation between the absence of optical absorption gaps and severe neutropenia has been observed. However, a completely accurate identification of the physical origin of these optical absorption gaps for conclusive neutropenia diagnosis remains an elusive task. Here we present scattering oblique plane microscopy as a means of imaging moving scattering particles within a turbid medium with the goal of eventually imaging and characterizing blood cells in vivo flowing in superficial capillaries. Our imaging system illuminates an oblique light sheet through a capillary bed and collects back-scatter using a single objective at frame rates of >200 Hz. To validate this system, we develop phantoms mimicking capillaries with 200 μm diameter lumens embedded deep in silicone doped with TiO₂ and India ink. Single 3 μm diameter polystyrene beads flowing through the capillaries are resolved with a signal to noise ratio of approximately 5:1 at a depth of 1 mean free path.

Date Published: 4 March 2019
PDF: 7 pages
Proc. SPIE 10890, Label-free Biomedical Imaging and Sensing (LBIS) 2019, 108902K (4 March 2019); doi: 10.1117/12.2509865

Published in SPIE Proceedings Vol. 10890:
Label-free Biomedical Imaging and Sensing (LBIS) 2019
Natan T. Shaked; Oliver Hayden, Editor(s)