Dr. David Levitz Profile

Dr. David Levitz

Co-Founder & CTO at MobileODT Ltd

SPIE Involvement:

Conference Chair | Editor | Author

Publications (34)

SPIE Conference Volume | May 14, 2018

Optics and Biophotonics in Low-Resource Settings IV

PROCEEDINGS ARTICLE | February 19, 2018

Optical tests for using smartphones inside medical devices

Proc. SPIE. 10486, Design and Quality for Biomedical Technologies XI

KEYWORDS: Biomedical optics, Cameras, Calibration, Skin, Diagnostics, Optical testing, Medical imaging, Medical devices, Biomedical engineering, Communication engineering

Read Abstract

PROCEEDINGS ARTICLE | February 13, 2018

Scattering and absorption measurements of cervical tissues measures using low cost multi-spectral imaging

Proc. SPIE. 10485, Optics and Biophotonics in Low-Resource Settings IV

KEYWORDS: Optical imaging, Light emitting diodes, Data modeling, Optical properties, Tissues, Scattering, Blood, Cervical cancer, Scatter measurement, Absorption

Read Abstract

PROCEEDINGS ARTICLE | February 13, 2018

Smartphone-coupled rhinolaryngoscopy at the point of care

Proc. SPIE. 10485, Optics and Biophotonics in Low-Resource Settings IV

KEYWORDS: Point-of-care devices, Databases, Video, Pathology, Control systems, Clouds, Endoscopes, Software development, Medical devices, Image storage

Read Abstract

PROCEEDINGS ARTICLE | February 13, 2018

Characterization of cervigram image sharpness using multiple self-referenced measurements and random forest classifiers

Proc. SPIE. 10485, Optics and Biophotonics in Low-Resource Settings IV

KEYWORDS: Cancer, Image segmentation, Image analysis, Cervix, Image quality, Digital imaging, Feature selection, Cervical cancer, Algorithm development

Read Abstract

SPIE Conference Volume | April 7, 2017

Optics and Biophotonics in Low-Resource Settings III

PROCEEDINGS ARTICLE | March 3, 2017

Cloud-based processing of multi-spectral imaging data

Proc. SPIE. 10055, Optics and Biophotonics in Low-Resource Settings III

KEYWORDS: Image compression, Tissues, Cameras, Image segmentation, Image processing, Video, Spectroscopy, Reflectivity, Clouds, Cervix

Read Abstract

PROCEEDINGS ARTICLE | March 3, 2017

Measurement and evaluation of digital cervicography programs in two cervical cancer screening camps in East Africa

Proc. SPIE. 10055, Optics and Biophotonics in Low-Resource Settings III

KEYWORDS: Light sources, Cell phones, Cancer, Translational research, Visualization, Tissues, Diagnostics, Cervix, Digital imaging, Cervical cancer

Read Abstract

PROCEEDINGS ARTICLE | March 3, 2017

Development and testing of a homogenous multi-wavelength LED light source

Proc. SPIE. 10055, Optics and Biophotonics in Low-Resource Settings III

KEYWORDS: Light sources, Light emitting diodes, Data modeling, Tissues, Imaging systems, Cameras, Light scattering, Multispectral imaging, Image transmission, Tissue optics

Read Abstract

SPIE Conference Volume | May 23, 2016

Optics and Biophotonics in Low-Resource Settings II

PROCEEDINGS ARTICLE | March 11, 2016

Development and bench testing of a multi-spectral imaging technology built on a smartphone platform

Proc. SPIE. 9699, Optics and Biophotonics in Low-Resource Settings II

KEYWORDS: Light emitting diodes, Cell phones, Visualization, Tissues, Imaging systems, Cameras, Blood, Imaging technologies, Cervix, Cervical cancer

Read Abstract

PROCEEDINGS ARTICLE | March 11, 2016

Mobile colposcopy in urban and underserved suburban areas in Baja California

Proc. SPIE. 9699, Optics and Biophotonics in Low-Resource Settings II

KEYWORDS: Cancer, Visualization, Image processing, Biopsy, Cervix, Image quality, Cell biology, Image enhancement, Cervical cancer, Outreach programs

Read Abstract

PROCEEDINGS ARTICLE | March 7, 2016

Initial clinical testing of a multi-spectral imaging system built on a smartphone platform

Proc. SPIE. 9699, Optics and Biophotonics in Low-Resource Settings II

KEYWORDS: Light emitting diodes, Cancer, Visualization, Imaging systems, Scattering, Image acquisition, Biopsy, Cervix, Cervical cancer, Absorption

Read Abstract

PROCEEDINGS ARTICLE | July 17, 2015

Epithelial cancers and photon migration: Monte Carlo simulations and diffuse reflectance measurements

Proc. SPIE. 9540, Novel Biophotonics Techniques and Applications III

KEYWORDS: Diffuse reflectance spectroscopy, Tissues, Diffusion, Reflectivity, Cervix, Monte Carlo methods, Tissue optics, Algorithm development, Photon transport, Absorption

Read Abstract

SPIE Conference Volume | April 7, 2015

Optics and Biophotonics in Low-Resource Settings

PROCEEDINGS ARTICLE | March 12, 2015

Cellphone based mobile colposcope for the evaluation of women with abnormal cervical cancer screening

Proc. SPIE. 9314, Optics and Biophotonics in Low-Resource Settings

KEYWORDS: Eye, Light emitting diodes, Cancer, Image analysis, Biopsy, Cervix, Image filtering, Cervical cancer, Optical mounts, Standards development

Read Abstract

PROCEEDINGS ARTICLE | March 12, 2015

Remote quality assurance in cervical cancer screening in low resource settings using a handheld smartphone-based colposcope

Proc. SPIE. 9314, Optics and Biophotonics in Low-Resource Settings

KEYWORDS: Mobile devices, Light sources, Eye, Light emitting diodes, Cancer, Image analysis, Optical inspection, Cervix, Cervical cancer, Tissue optics

Read Abstract

PROCEEDINGS ARTICLE | March 12, 2015

Optical design of low cost imaging systems for mobile medical applications

Proc. SPIE. 9314, Optics and Biophotonics in Low-Resource Settings

KEYWORDS: Cell phones, Imaging systems, Cameras, Sensors, Distortion, Lens design, Imaging devices, Cervix, Medical imaging, Medical devices

Read Abstract

PROCEEDINGS ARTICLE | February 9, 2012

Attenuation fluctuations and local dermal reflectivity are indicators of immune cell infiltrate and epidermal hyperplasia in skin inflammation

Proc. SPIE. 8207, Photonic Therapeutics and Diagnostics VIII

KEYWORDS: Coherence imaging, Tissues, Signal attenuation, Optical coherence tomography, Skin, Reflectivity, Control systems, Inflammation, Ear, In vivo imaging

Read Abstract

SPIE Journal Paper | April 1, 2011

Dermal reflectivity determined by optical coherence tomography is an indicator of epidermal hyperplasia and dermal edema within inflamed skin

Phillips, Kevin , Wang, Yun , Choudhury, Niloy , Swanzey, Emily , Lagowski, James , Kulesz-Martin, Molly , Jacques, Steven , Levitz, David

JBO Vol. 16 Issue 04

KEYWORDS: Optical coherence tomography, Reflectivity, Skin, Ear, Tissues, Inflammation, In vivo imaging, Coherence imaging, Signal attenuation, Scattering

Read Abstract

DOWNLOAD PDF

SPIE Journal Paper | March 1, 2010

Quantitative characterization of developing collagen gels using optical coherence tomography

Levitz, David , Hinds, Monica , Choudhury, Niloy , Tran, Noi , Hanson, Stephen , Jacques, Steven

JBO Vol. 15 Issue 02

KEYWORDS: Collagen, Optical coherence tomography, Optical properties, Scattering, Reflectivity, Signal attenuation, Tissues, Anisotropy, Optical spheres, Data modeling

Read Abstract

DOWNLOAD PDF

PROCEEDINGS ARTICLE | February 25, 2010

Statistical characterization of engineered tissues using confocal mosaic technology

Proc. SPIE. 7566, Optics in Tissue Engineering and Regenerative Medicine IV

KEYWORDS: Microelectromechanical systems, Confocal microscopy, Statistical analysis, Tissues, Luminescence, Reflectivity, Collagen, Optical engineering, Spatial resolution, Tissue optics

Read Abstract

PROCEEDINGS ARTICLE | February 20, 2010

Characterizing matrix remodeling in collagen gels using optical coherence tomography

Proc. SPIE. 7554, Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIV

KEYWORDS: Microelectromechanical systems, Optical properties, Visualization, Tissues, Scattering, Signal attenuation, Optical coherence tomography, Reflectivity, Collagen, Anisotropy

Read Abstract

PROCEEDINGS ARTICLE | February 24, 2009

Optically characterizing collagen gels made with different cell types

Proc. SPIE. 7179, Optics in Tissue Engineering and Regenerative Medicine III

KEYWORDS: Data modeling, Optical properties, Tissues, Scattering, Signal attenuation, Optical coherence tomography, Reflectivity, Control systems, Collagen, Anisotropy

Read Abstract

The ability of optical imaging techniques such as optical coherence tomography (OCT) to non-destructively characterize tissue-engineered constructs has generated enormous interest recently. Collagen gels are 3D structures that represent a simple common model of many engineered tissues that contain 2 primary scatterers: collagen and cells. We are testing the ability of OCT data to characterize the remodeling of such collagen-based constructs by 3 different types of cells: vascular smooth muscle cells (SMCs), endothelial cells (ECs), and osteoblasts (OBs). Collagen gels were prepared with SMCs, ECs, and OBs with a seeding density of 1×10⁶ cells/ml; additionally, acellular controls were also prepared. The disk-shaped constructs were allowed to remodel in the incubator for 5 days, with OCT imaging occurring on days 1 and 5. From the OCT data, the attenuation and reflectivity were evaluated by fitting the data to a theoretical model that relates the tissue optical properties (scattering coefficient and anisotropy factor) and imaging conditions to the OCT signal. The degree of gel compaction was determined from the volume of the culture medium that feeds the constructs. We found that gel compaction (relative to the acellular control) occurred in the SMC constructs, but not in the OB or EC constructs. The optical property data showed that at day 5 the SMC constructs had an overall higher reflectivity (lower g) relative to day 1, whereas there was no obvious change in reflectivity of the EC, OB constructs and acellular controls relative to day 1. Moreover, there was a difference in the attenuation of the OB constructs on day 5 relative to day 1, but not in the other constructs. The apparent decrease in anisotropy observed in the SMC constructs, but not in the OB and EC constructs and acellular controls, suggests that OCT is sensitive to the remodeling of the collagen matrix that accompanies gel compaction, and can offer highly localized information on the construct microstructure. The apparent increase in the scattering coefficient of the OB constructs is believed to be caused by a higher rate of proliferation by these cell types relative to the others. Overall, these results suggest that the optical properties of collagen gels contain information on both cell number and collagen gel microstructure.

PROCEEDINGS ARTICLE | February 12, 2009

The effect of wavelength on optical properties extracted from images of engineered tissue

Proc. SPIE. 7179, Optics in Tissue Engineering and Regenerative Medicine III

KEYWORDS: Confocal microscopy, Data modeling, Optical properties, Scattering, Signal attenuation, Optical coherence tomography, Reflectivity, Collagen, Tissue optics, Anisotropy

Read Abstract

Optical imaging modalities such as confocal microscopy and optical coherence tomography (OCT) are emerging as appealing methods for non-destructive evaluation of engineered tissues. The information offered by such optical imaging methods depends on the wavelength vis-á-vis the optical scattering properties of the sample. These properties affect many factors critical to image analysis in a nonlinear and nontrivial manner. Thus, we sought to characterize the effect wavelength has on the optical properties collagen remodeled by cells at 3 common imaging wavelengths: 488, 633, and 1310 nm. To do this, we seeded smooth muscle cells (SMCs) in soluble collagen gels at a density of 1×106 cells/ml; similar acellular control constructs were also prepared. The constructs were allowed to remodel in the incubator for 5 days, and were examined at 24 and 120 hours by confocal imaging at 488 and 633 nm, and by OCT imaging at 1310 nm. From the confocal and OCT data, the attenuation and reflectivity were evaluated by fitting the data to a theoretical model that relates the tissue optical properties (scattering coefficient and anisotropy factor) and imaging conditions to the signal. In general, we found that at 1310 nm, the optical properties of the acellular control constructs had a lower reflectivity (higher anisotropy) than the SMC constructs. The difference in reflectivity between the SMC construct and acellular controls tended to decrease with wavelength, owing to a relative increase in reflectivity of acellular controls at lower wavelengths relative to the cellular constructs. Overall, the largest difference in optical properties occurred at 1310 nm. Taken together, the data show that the shift in optical properties of soluble collagen gels caused by cellular remodeling is nonlinearly wavelength dependent, and that this information should be considered when devising how to optimally characterize engineered tissues using optical imaging methods.

PROCEEDINGS ARTICLE | March 1, 2008

Measuring tissue optical properties in vivo using reflectance-mode confocal microscopy and OCT

Proc. SPIE. 6864, Biomedical Applications of Light Scattering II

KEYWORDS: Confocal microscopy, Tissues, Scattering, Signal attenuation, Optical coherence tomography, Photons, Light scattering, Reflectivity, Monte Carlo methods, Tissue optics

Read Abstract

PROCEEDINGS ARTICLE | February 21, 2008

Microscopic heterogeneity vs. macroscopic homogeneity in tissue phantoms using reflectance-mode confocal scanning laser microscopy

Proc. SPIE. 6870, Design and Performance Validation of Phantoms Used in Conjunction with Optical Measurements of Tissue

KEYWORDS: Confocal microscopy, Optical spheres, Optical properties, Scattering, Microscopy, Particles, Laser scattering, Chemical elements, Laser tissue interaction, Anisotropy

Read Abstract

PROCEEDINGS ARTICLE | February 21, 2008

Evaluating optical properties of isolated biological scatterers from confocal and low-coherence images

Proc. SPIE. 6870, Design and Performance Validation of Phantoms Used in Conjunction with Optical Measurements of Tissue

KEYWORDS: Confocal microscopy, Optical properties, Tissues, Scattering, Signal attenuation, Optical coherence tomography, Particles, Light scattering, Collagen, Mie scattering

Read Abstract

PROCEEDINGS ARTICLE | February 6, 2008

Optically characterizing vascular tissue constructs made with soluble versus homogenized collagen

Proc. SPIE. 6858, Optics in Tissue Engineering and Regenerative Medicine II

KEYWORDS: Data modeling, Optical properties, Scattering, Signal attenuation, Optical coherence tomography, Image processing, Reflectivity, Collagen, Tissue optics, Anisotropy

Read Abstract

PROCEEDINGS ARTICLE | February 7, 2007

A tissue-engineered 3D model of light scattering in atherosclerotic plaques

Proc. SPIE. 6439, Optics in Tissue Engineering and Regenerative Medicine

KEYWORDS: Optical fibers, Foam, Tissues, Scattering, Optical coherence tomography, Particles, Light scattering, 3D modeling, Collagen, Tissue optics

Read Abstract

PROCEEDINGS ARTICLE | July 21, 2006

Monitoring cellular remodeling of collageneous matrix using optical coherence tomography

Proc. SPIE. 6163, Saratov Fall Meeting 2005: Optical Technologies in Biophysics and Medicine VII

KEYWORDS: Biomedical optics, Optical properties, Tissues, Scattering, Optical coherence tomography, Image processing, Collagen, Optical phantoms, Signal processing, Tissue optics

Read Abstract

PROCEEDINGS ARTICLE | February 22, 2006

Measuring optical properties of a blood vessel model using optical coherence tomography

Proc. SPIE. 6078, Photonic Therapeutics and Diagnostics II

KEYWORDS: Data modeling, Optical properties, Tissues, Scattering, Optical coherence tomography, Image segmentation, Image processing, Collagen, Signal processing, Tissue optics

Read Abstract

PROCEEDINGS ARTICLE | June 22, 2005

Extraction of tissue optical properties from optical coherence tomography images for diagnostic purposes

Proc. SPIE. 5771, Saratov Fall Meeting 2004: Optical Technologies in Biophysics and Medicine VI

KEYWORDS: Extremely high frequency, Data modeling, Optical properties, Tissues, Scattering, Signal attenuation, Optical coherence tomography, Integrating spheres, Tissue optics, Systems modeling

Read Abstract

PROCEEDINGS ARTICLE | October 2, 2003

Assessing blood vessel abnormality via extracting scattering properties from OCT images

Proc. SPIE. 5140, Optical Coherence Tomography and Coherence Techniques

KEYWORDS: Computer aided diagnosis and therapy, Tissues, Scattering, Blood vessels, Optical coherence tomography, Interfaces, Arteries, Collagen, Tissue optics, Anisotropy

Read Abstract

Background: Coronary artery disease (CAD) is the leading cause of mortality and morbidity in the industrialized world. Optical coherence tomography (OCT) is a high-resolution intravascular imaging technology with a potential for in vivo plaque characterization. Although structural remodeling of the arterial vessel wall during plaque development can change tissue optical scattering properties, very limited evidence is available on the exact optical scattering properties of plaques. The scattering coefficient, μs, and the anisotropy factor, g, can be derived from OCT images by fitting a theoretical model to individual depth-scans. The aim of the current study was to use this method to examine by OCT the scattering properties of human arteries with different stages of atherosclerotic lesion development. Methods: Normal (n=4), lipid-rich (n=4), and fibrous (n=3) aortic blocks as classified by parallel histopathologic examination were obtained within 24 hours of death and imaged by OCT. The intima was located in the OCT images, and then further split into 115 blocks (41 normal, 40 lipid-rich, and 34 fibrous) of adjacent OCT depth-scans transversely spanning ~200-300 μm. Scattering signals from each block were averaged and fit to the theoretical model. From these fittings, μs and g were extracted. Results and Discussion: The optical scattering properties of normal aortic intima were quite different from lipid-rich and fibrous lesions, respectively. We discovered that the normal intima was generally highly forward scattering, i.e., with 0.917-1, whereas lipid-rich blocks had μs<15mm^-1. Fibrous blocks displayed large variations in μs, reflecting a histopathology with varying amounts of collagen, lipids, and elastin. Based on our findings, we defined a criteria of μs and g for normal intimas, using the above values of μs and g as cutoffs. Our "normal" criteria demonstrated high sensitivity (92.4%) and specificity (82.4%). We conclude, that a detailed analysis of the tissue optical scattering properties can enhance the capacity of OCT to provide information about vascular pathology.

Showing 5 of 34 publications

Conference Committee Involvement (5)

Optics and Biophotonics in Low-Resource Settings V

2 February 2019 | San Francisco, California, United States

Optics and Biophotonics in Low-Resource Settings IV

27 January 2018 | San Francisco, California, United States

Optics and Biophotonics in Low-Resource Settings III

28 January 2017 | San Francisco, California, United States

Optics and Biophotonics in Low-Resource Settings II

13 February 2016 | San Francisco, California, United States

Optics and Biophotonics in Low-Resource Settings

7 February 2015 | San Francisco, California, United States

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years