Optical Phantoms: Diffuse and Sub-diffuse Imaging and Spectroscopy Validation

Greening, Gage J.; James, Haley M.; Muldoon, Timothy J.

doi:10.1117/3.2226012

Cited by 5 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2,11,12,25 Information regarding software requirements for converting reflectance spectra into optical parameters can be found elsewhere. 11,24,26 In regards to troubleshooting, spectra resulting in poor fits (average percent errors greater than 10% between raw data and fitted data) These simple improvements should fix the accurate fitting of sub-diffuse reflectance spectra, and if questions remain, spectra can be validated with phantoms with known optical properties (reduced scattering and absorption coefficients).…”

Section: Discussionmentioning

confidence: 99%

Multimodal Imaging and Spectroscopy Fiber-bundle Microendoscopy Platform for Non-invasive, <em>In Vivo</em> Tissue Analysis

Greening

Rajaram

Muldoon

2016

JoVE

Self Cite

View full text Add to dashboard Cite

Recent fiber-bundle microendoscopy techniques enable non-invasive analysis of in vivo tissue using either imaging techniques or a combination of spectroscopy techniques. Combining imaging and spectroscopy techniques into a single optical probe may provide a more complete analysis of tissue health. In this article, two dissimilar modalities are combined, high-resolution fluorescence microendoscopy imaging and diffuse reflectance spectroscopy, into a single optical probe. High-resolution fluorescence microendoscopy imaging is a technique used to visualize apical tissue micro-architecture and, although mostly a qualitative technique, has demonstrated effective real-time differentiation between neoplastic and non-neoplastic tissue. Diffuse reflectance spectroscopy is a technique which can extract tissue physiological parameters including local hemoglobin concentration, melanin concentration, and oxygen saturation. This article describes the specifications required to construct the fiber-optic probe, how to build the instrumentation, and then demonstrates the technique on in vivo human skin. This work revealed that tissue micro-architecture, specifically apical skin keratinocytes, can be co-registered with its associated physiological parameters. The instrumentation and fiber-bundle probe presented here can be optimized as either a handheld or endoscopically-compatible device for use in a variety of organ systems. Additional clinical research is needed to test the viability of this technique for different epithelial disease states. Video LinkThe video component of this article can be found at

show abstract

Section: Discussionmentioning

confidence: 99%

Multimodal Imaging and Spectroscopy Fiber-bundle Microendoscopy Platform for Non-invasive, <em>In Vivo</em> Tissue Analysis

Greening

Rajaram

Muldoon

2016

JoVE

Self Cite

View full text Add to dashboard Cite

show abstract

“…Since scattering contributes much more to reflectance intensity compared to absorption, the μ a was held constant at 0 cm −1 66 . Additionally, the phantom “epithelia” was made to be 300 μm thick to approximately simulate the thickness of oral mucosa 67 . With the understanding that the 374 and 730 μm SDSs sample different depths, it was expected that the 374 μm SDS may be more sensitive to shallower, epithelial-confined scattering changes associated with early dysplasia.…”

Section: Methodsmentioning

confidence: 99%

“…For each geometry in Fig. 4 , two 150 μm layers were stacked to generate the desired phantom 67 68 . The total phantom “epithelial” thickness was thus 300 μm, not including the “stromal” semi-infinite base layer, which was 1 cm thick.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Towards monitoring dysplastic progression in the oral cavity using a hybrid fiber-bundle imaging and spectroscopy probe

Greening

James

Dierks

et al. 2016

Sci Rep

Self Cite

View full text Add to dashboard Cite

Intraepithelial dysplasia of the oral mucosa typically originates in the proliferative cell layer at the basement membrane and extends to the upper epithelial layers as the disease progresses. Detection of malignancies typically occurs upon visual inspection by non-specialists at a late-stage. In this manuscript, we validate a quantitative hybrid imaging and spectroscopy microendoscope to monitor dysplastic progression within the oral cavity microenvironment in a phantom and pre-clinical study. We use an empirical model to quantify optical properties and sampling depth from sub-diffuse reflectance spectra (450–750 nm) at two source-detector separations (374 and 730 μm). Average errors in recovering reduced scattering (5–26 cm−1) and absorption coefficients (0–10 cm−1) in hemoglobin-based phantoms were approximately 2% and 6%, respectively. Next, a 300 μm-thick phantom tumor model was used to validate the probe’s ability to monitor progression of a proliferating optical heterogeneity. Finally, the technique was demonstrated on 13 healthy volunteers and volume-averaged optical coefficients, scattering exponent, hemoglobin concentration, oxygen saturation, and sampling depth are presented alongside a high-resolution microendoscopy image of oral mucosa from one volunteer. This multimodal microendoscopy approach encompasses both structural and spectroscopic reporters of perfusion within the tissue microenvironment and can potentially be used to monitor tumor response to therapy.

show abstract

“…The μ a was calculated by measuring a diluted solution of teal India ink in distilled water using a spectrophotometer (5102-00, PerkinElmer) and the Beer-Lambert Law. [18][19][20]26 A 5 × 3 (15 total) set of calibration phantoms was created, corresponding to five scattering ranges and three absorbing ranges ( Fig. 3).…”

Section: Optical Phantomsmentioning

confidence: 99%

Sampling depth of a diffuse reflectance spectroscopy probe for in-vivo physiological quantification of murine subcutaneous tumor allografts

et al. 2018

Self Cite

View full text Add to dashboard Cite

Diffuse reflectance spectroscopy (DRS) is a probe-based spectral biopsy technique used in cancer studies to quantify tissue reduced scattering (μs') and absorption (μa) coefficients and vary in source-detector separation (SDS) to fine-tune sampling depth. In subcutaneous murine tumor allografts or xenografts, a key design requirement is ensuring that the source light interrogates past the skin layer into the tumor without significantly sacrificing signal-to-noise ratio (target of ≥15 dB). To resolve this requirement, a DRS probe was designed with four SDSs (0.75, 2.00, 3.00, and 4.00 mm) to interrogate increasing tissue volumes between 450 and 900 nm. The goal was to quantify percent errors in extracting μa and μs', and to quantify sampling depth into subcutaneous Balb/c-CT26 colon tumor allografts. Using an optical phantom-based experimental method, lookup-tables were constructed relating μa,μs', diffuse reflectance, and sampling depth. Percent errors were <10 % and 5% for extracting μa and μs', respectively, for all SDSs. Sampling depth reached up to 1.6 mm at the first Q-band of hemoglobin at 542 nm, the key spectral region for quantifying tissue oxyhemoglobin concentration. This work shows that the DRS probe can accurately extract optical properties and the resultant physiological parameters such as total hemoglobin concentration and tissue oxygen saturation, from sufficient depth within subcutaneous Balb/c-CT26 colon tumor allografts. Methods described here can be generalized for other murine tumor models. Future work will explore the feasibility of the DRS in quantifying volumetric tumor perfusion in response to anticancer therapies.

show abstract

Optical Phantoms: Diffuse and Sub-diffuse Imaging and Spectroscopy Validation

Cited by 5 publications

References 0 publications

Multimodal Imaging and Spectroscopy Fiber-bundle Microendoscopy Platform for Non-invasive, <em>In Vivo</em> Tissue Analysis

Multimodal Imaging and Spectroscopy Fiber-bundle Microendoscopy Platform for Non-invasive, <em>In Vivo</em> Tissue Analysis

Towards monitoring dysplastic progression in the oral cavity using a hybrid fiber-bundle imaging and spectroscopy probe

Sampling depth of a diffuse reflectance spectroscopy probe for in-vivo physiological quantification of murine subcutaneous tumor allografts

Contact Info

Product

Resources

About