Refractive errors and corrections for OCT images in an inflated lung phantom

Golabchi, Ali; Faust, Jessica L.; Golabchi, Fatemeh Noushin; Brooks, Dana H.; Gouldstone, Andrew; DiMarzio, Charles A.

doi:10.1364/boe.3.001101

Cited by 10 publications

(7 citation statements)

References 21 publications

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“…It is also important to note that the lung is inherently a very porous organ because of the distal airways and the alveoli. While that is not represented in this phantom, the optical effects of similar structures have been observed using a Bragg-Nye bubble raft for optical coherence tomography 21 , air bubbles in olive oil 42 , and shaving cream or dish detergent for nuclear magnetic resonance imaging 43 . Creating polymer foams with reproducible characteristics may be able to reconcile this difference between the solid phantoms presented here and the lung microstructure 44 .…”

Section: Recipes For Materials With Different Optical Properties Are mentioning

confidence: 69%

Fabrication and Characterization of Optical Tissue Phantoms Containing Macrostructure

Durkee

Nash

Nooshabadi

et al. 2018

JoVE

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The rapid development of new optical imaging techniques is dependent on the availability of low-cost, customizable, and easily reproducible standards. By replicating the imaging environment, costly animal experiments to validate a technique may be circumvented. Predicting and optimizing the performance of in vivo and ex vivo imaging techniques requires testing on samples that are optically similar to tissues of interest. Tissue-mimicking optical phantoms provide a standard for evaluation, characterization, or calibration of an optical system. Homogenous polymer optical tissue phantoms are widely used to mimic the optical properties of a specific tissue type within a narrow spectral range. Layered tissues, such as the epidermis and dermis, can be mimicked by simply stacking these homogenous slab phantoms. However, many in vivo imaging techniques are applied to more spatially complex tissue where three dimensional structures, such as blood vessels, airways, or tissue defects, can affect the performance of the imaging system. This protocol describes the fabrication of a tissue-mimicking phantom that incorporates three-dimensional structural complexity using material with optical properties of tissue. Look-up tables provide India ink and titanium dioxide recipes for optical absorption and scattering targets. Methods to characterize and tune the material optical properties are described. The phantom fabrication detailed in this article has an internal branching mock airway void; however, the technique can be broadly applied to other tissue or organ structures.

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Section: Recipes For Materials With Different Optical Properties Are mentioning

confidence: 69%

Fabrication and Characterization of Optical Tissue Phantoms Containing Macrostructure

Durkee

Nash

Nooshabadi

et al. 2018

JoVE

View full text Add to dashboard Cite

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“…The OPL is the product of RI and the physical distance that light travels when it propagates through the sample. The determination of the sample RI map is a challenging problem that has been tackled by several groups 5,7,27 including ours. 14 Our overarching method described in Sec.…”

Section: Mathematical Modelsmentioning

confidence: 99%

“…5 Lung tissue, for example, demonstrates RI variability because there is air (RI ¼ 1.00) in the alveoli, which are surrounded by cellular material with RI between 1.30 and 1.41. 6,7 3-D imaging of such specimen with wide-field microscopy suffers from both defocus and spherical aberration (SA). 3-D imaging with confocal or structured illumination microscopy, although not affected by defocus, is still prone to SA.…”

Section: Introductionmentioning

confidence: 99%

Fluorescence microscopy point spread function model accounting for aberrations due to refractive index variability within a specimen

Ghosh

Preza

2015

J. Biomed. Opt

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Abstract. A three-dimensional (3-D) point spread function (PSF) model for wide-field fluorescence microscopy, suitable for imaging samples with variable refractive index (RI) in multilayered media, is presented. This PSF model is a key component for accurate 3-D image restoration of thick biological samples, such as lung tissue. Microscope-and specimen-derived parameters are combined with a rigorous vectorial formulation to obtain a new PSF model that accounts for additional aberrations due to specimen RI variability. Experimental evaluation and verification of the PSF model was accomplished using images from 175-nm fluorescent beads in a controlled test sample. Fundamental experimental validation of the advantage of using improved PSFs in depth-variant restoration was accomplished by restoring experimental data from beads (6 μm in diameter) mounted in a sample with RI variation. In the investigated study, improvement in restoration accuracy in the range of 18 to 35% was observed when PSFs from the proposed model were used over restoration using PSFs from an existing model. The new PSF model was further validated by showing that its prediction compares to an experimental PSF (determined from 175-nm beads located below a thick rat lung slice) with a 42% improved accuracy over the current PSF model prediction. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…These goals are the successful development of (1) a methodology to derive the sample RI distribution; (2) an accurate but practical PSF model that accounts for specimen RI variability, which we reported elsewhere; 32 (3) a computationally tractable SV forward imaging model; 23,33 and (4) a practical restoration algorithm based on the SV model. The determination of the sample RI map is a challenging problem that has been tackled by several groups [34][35][36][37][38] including ours, 39,40 and it is beyond the scope of this paper. In this paper, we focus on the mathematical formulation, simulation, and experimental validation in the development of the third and fourth goals, in which we integrate our new PSF model from the second goal.…”

Section: Introductionmentioning

confidence: 99%

Three-dimensional block-based restoration integrated with wide-field fluorescence microscopy for the investigation of thick specimens with spatially variant refractive index

Ghosh

Preza

2016

J. Biomed. Opt

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Development of a block-based restoration (BBR) method that addresses spatially variant (SV) imaging in wide-field fluorescence microscopy of thick samples is presented. The BBR method is based on a block-based imaging model, which approximates SV imaging using an efficient orthonormal basis decomposition of multiple SV point-spread functions computed at block vertices. The effect of reducing the number of blocks needed to account for SV imaging on the restoration accuracy was investigated with simulations using a numerical lung tissue phantom relevant to biological studies. Results show that reducing the number of blocks by 82% and 98% resulted in a 19% and 27% reduction in restoration accuracy, respectively, thereby establishing a reasonable tradeoff between computational resources and accuracy. Comparison of the BBR method to existing methods (deconvolution) that do not account for SV imaging demonstrates a 90% improvement in restoration accuracy. BBR results from synthetic and experimental images of a controlled test sample with SV refractive index (RI) show consistency, providing a validation of the BBR approach. In this study, information from DIC and fluorescence images was combined to identify regions with changing RI within the imaging volume. The BBR method provides a first step toward computationally tractable reconstruction of images from thick samples.

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Refractive errors and corrections for OCT images in an inflated lung phantom

Cited by 10 publications

References 21 publications

Fabrication and Characterization of Optical Tissue Phantoms Containing Macrostructure

Fabrication and Characterization of Optical Tissue Phantoms Containing Macrostructure

Fluorescence microscopy point spread function model accounting for aberrations due to refractive index variability within a specimen

Three-dimensional block-based restoration integrated with wide-field fluorescence microscopy for the investigation of thick specimens with spatially variant refractive index

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