Prof. Bernard Choi Profile

Prof. Bernard Choi

Professor at Beckman Laser Institute and Medical Clinic

SPIE Involvement:

Conference Program Committee | Editorial Board Member: Journal of Biomedical Optics | Author | Editor

Publications (95)

SPIE Journal Paper | 1 August 2024 Open Access

Open Access

Multimodal optical imaging of the oculofacial region using a solid tissue-simulating facial phantom

Lilangi S. Ediriwickrema, Shijun Sung, Kaylyn Mattick, Miranda An, Claire Malley, Stephanie Kirk, Divya Devineni, Jaylen Lee, Gordon Kennedy, Bernard Choi, Anthony Durkin

JBO, Vol. 29, Issue 08, 086002, (August 2024) https://doi.org/10.1117/12.10.1117/1.JBO.29.8.086002

KEYWORDS: Optical properties, Tissues, Optical imaging, Scattering, Light sources and illumination, Anatomy, Absorption, Optical testing, Biological imaging, Skin

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SignificanceSpatial frequency domain imaging (SFDI) applies patterned near-infrared illumination to quantify the optical properties of subsurface tissue. The periocular region is unique due to its complex ocular adnexal anatomy. Although SFDI has been successfully applied to relatively flat in vivo tissues, regions that have significant height variations and curvature may result in optical property inaccuracies.AimWe characterize the geometric impact of the periocular region on SFDI imaging reliability.ApproachSFDI was employed to measure the reduced scattering coefficient (μs′) and absorption coefficient (μa) of the periocular region in a cast facial tissue-simulating phantom by capturing images along regions of interest (ROIs): inferior temporal quadrant (ITQ), inferior nasal quadrant (INQ), superior temporal quadrant (STQ), central eyelid margin (CEM), rostral lateral nasal bridge (RLNB), and forehead (FH). The phantom was placed on a chin rest and imaged nine times from an “en face” or “side profile” position, and the flat back of the phantom was measured 15 times.ResultsThe measured μa and μs′ of a cast facial phantom are accurate when comparing the ITQ, INQ, STQ, and FH to its flat posterior surface. Paired t tests of ITQ, INQ, STQ, and FH μa and μs′ concluded that there is not enough evidence to suggest that imaging orientation impacted the measurement accuracy. Regions of extreme topographical variation, i.e., CEM and RLNB, did exhibit differences in measured optical properties.ConclusionsWe are the first to evaluate the geometric implications of wide-field imaging along the periocular region using a solid tissue-simulating facial phantom. Results suggest that the ITQ, INQ, STQ, and FH of a generalized face have minimal impact on the SFDI measurement accuracy. Areas with heightened topographic variation exhibit measurement variability. Device and facial positioning do not appear to bias measurements. These findings confirm the need to carefully select ROIs when measuring optical properties along the periocular region.

Proceedings Article | 13 March 2024 Presentation + Paper

Presentation + Paper

Effects of blood type and number concentration on the circulation time of micro-sized erythrocyte-derived optical particles in mice

G. Swajian, S. Zaman, C.-H. Lee, E. Nguyen, C. Huynh, O. Lai, J. Nelson, B. Choi, W. Jia, B. Anvari

Proceedings Volume 12859, 1285908 (2024) https://doi.org/10.1117/12.3003013

KEYWORDS: Blood, Near infrared, Particles, Fluorescence intensity, Fluorescence imaging, Fluorescence, Light absorption, Laser irradiation, Indocyanine green

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Proceedings Article | 13 March 2024 Presentation

Presentation

Hypertension provokes the development of cerebral microhemorrhages and vascular injury in a mouse model

Danny Xie, Christian Crouzet, Chuo Fang, Han Liu, Jihua Liu, Donghy Lee, Adrian Vallejo, Annlia Paganini-Hill, Wei Ling Lau, David Cribbs, Mark Fisher, Bernard Choi

Proceedings Volume PC12828, PC128280J (2024) https://doi.org/10.1117/12.3002206

KEYWORDS: Mouse models, Injuries, Cerebral blood flow, Brain, Blood circulation, Animal model studies, Neuroimaging, Magnetic resonance imaging, Laser speckle imaging, 3D image processing

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Proceedings Article | 13 March 2024 Presentation

Presentation

Optical properties of in-vivo normal and burned skin in humans and swine measured using spatial frequency domain imaging (SFDI)

Gordon Kennedy, Rebecca Rowland, Thinh Phan, Chris Campbell, Alexis Fox, Earl Steward, Bernard Choi, Theresa Chin, Victor Joe, Anthony Durkin, Robert Christy, David Burmeister

Proceedings Volume PC12833, PC128330E (2024) https://doi.org/10.1117/12.3003470

KEYWORDS: Skin, Optical properties, In vivo imaging, Systems modeling, Tissues, Wound healing, Toxicology, Tissue optics, Pathophysiology, Oxygen

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Proceedings Article | 13 March 2024 Presentation

Presentation

Three-dimensional visualization of cerebrovascular metrics in 3xTg mouse models of Alzheimer's disease

Mio Jiang, Danny Xie, Christian Crouzet, Bernard Choi

Proceedings Volume PC12828, PC128280G (2024) https://doi.org/10.1117/12.3003103

KEYWORDS: Visualization, Mouse models, Alzheimer disease, 3D modeling, Brain, Animal model studies, Pathogens, Optical microscopy, MATLAB, Biomedical optics

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SPIE Journal Paper | 19 December 2023 Open Access

Open Access

Quantifying tissue properties and absolute hemodynamics using coherent spatial imaging

Christian Crouzet, Cody E. Dunn, Bernard Choi

JBO, Vol. 28, Issue 12, 127001, (December 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.12.127001

KEYWORDS: Blood circulation, Tissues, Optical properties, Hemodynamics, Sensors, Coherence imaging, Tissue optics, Optical testing, In vivo imaging, Reflectivity

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SPIE Journal Paper | 5 December 2023 Open Access

Open Access

Improved spatial speckle contrast model for tissue blood flow imaging: effects of spatial correlation among neighboring camera pixels

Julio Cesar Juarez-Ramirez, Beatriz Coyotl-Ocelotl, Bernard Choi, Ruben Ramos-Garcia, Teresita Spezzia-Mazzocco, Julio C. Ramirez-San-Juan

JBO, Vol. 28, Issue 12, 125002, (December 2023) https://doi.org/10.1117/12.10.1117/1.JBO.28.12.125002

KEYWORDS: Speckle, Windows, Blood circulation, Tissues, Cameras, Speckle pattern, Data modeling, Laser speckle contrast imaging, Mathematical modeling, Autocorrelation

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SPIE Journal Paper | 3 October 2023 Open Access

Open Access

Quantitative hemodynamic imaging: a method to correct the effects of optical properties on laser speckle imaging

Thinh Phan, Christian Crouzet, Gordon T. Kennedy, Anthony J. Durkin, Bernard Choi

NPh, Vol. 10, Issue 04, 045001, (October 2023) https://doi.org/10.1117/12.10.1117/1.NPh.10.4.045001

KEYWORDS: Optical properties, Hemodynamics, Digital micromirror devices, Speckle, Imaging systems, Neurophotonics, Cameras, Animals, Silicon, Light sources and illumination

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SignificanceStudying cerebral hemodynamics may provide diagnostic information on neurological conditions. Wide-field imaging techniques, such as laser speckle imaging (LSI) and optical intrinsic signal imaging, are commonly used to study cerebral hemodynamics. However, they often do not account appropriately for the optical properties of the brain that can vary among subjects and even during a single measurement. Here, we describe the combination of LSI and spatial-frequency domain imaging (SFDI) into a wide-field quantitative hemodynamic imaging (QHI) system that can correct the effects of optical properties on LSI measurements to achieve a quantitative measurement of cerebral blood flow (CBF).AimWe describe the design, fabrication, and testing of QHI.ApproachThe QHI hardware combines LSI and SFDI with spatial and temporal synchronization. We characterized system sensitivity, accuracy, and precision with tissue-mimicking phantoms. With SFDI optical property measurements, we describe a method derived from dynamic light scattering to obtain absolute CBF values from LSI and SFDI measurements. We illustrate the potential benefits of absolute CBF measurements in resting-state and dynamic experiments.ResultsQHI achieved a 50-Hz raw acquisition frame rate with a 10 × 10 mm field of view and flow sensitivity up to ∼4 mm / s. The extracted SFDI optical properties agreed well with a commercial system (R2 ≥ 0.98). The system showed high stability with low coefficients of variations over multiple sessions within the same day (<1 % ) and over multiple days (<4 % ). When optical properties were considered, the in-vivo hypercapnia gas challenge showed a slight difference in CBF (−1.5 % to 0.5% difference). The in-vivo resting-state experiment showed a change in CBF ranking for nine out of 13 animals when the correction method was applied to LSI CBF measurements.ConclusionsWe developed a wide-field QHI system to account for the confounding effects of optical properties on CBF LSI measurements using the information obtained from SFDI.

SPIE Journal Paper | 2 May 2023 Open Access

Open Access

Intrinsic, widefield optical imaging of hemodynamics in rodent models of Alzheimer’s disease and neurological injury

Christian Crouzet, Thinh Phan, Robert H. Wilson, Teo Jeon Shin, Bernard Choi

NPh, Vol. 10, Issue 02, 020601, (May 2023) https://doi.org/10.1117/12.10.1117/1.NPh.10.2.020601

KEYWORDS: Hemodynamics, Optical imaging, Animal model studies, Brain, Tissues, Blood circulation, Speckle, Neurophotonics, Injuries, Optical properties

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Proceedings Article | 17 March 2023 Presentation

Presentation

Absolute measurement of blood flow using a wide-field cerebral metabolic imaging (CMI) system

Thinh Phan, Christian Crouzet, Gordon Kennedy, Anthony Durkin, Bernard Choi

Proceedings Volume PC12365, PC1236502 (2023) https://doi.org/10.1117/12.2648084

KEYWORDS: Imaging systems, Blood circulation, Speckle, Dubnium, Optical testing, Optical properties, Diffusion, Scattering, Pixel resolution, Oxygen

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Proceedings Article | 17 March 2023 Presentation

Presentation

Quantification of cerebral microhemorrhages with three-dimensional histology

Danny Xie, Christian Crouzet, Chuo Fang, Jihua Liu, Han Liu, Wei Ling Lau, David Cribbs, Mark Fisher, Bernard Choi

Proceedings Volume PC12365, PC1236506 (2023) https://doi.org/10.1117/12.2650417

KEYWORDS: Tissues, Visualization, Brain, Tissue clearing, Neuroimaging, Ischemic stroke, 3D image processing

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Proceedings Article | 7 March 2022 Presentation

Presentation

Quantifying tissue properties and absolute hemodynamics using coherent spatial imaging

Christian Crouzet, Cody Dunn, Bernard Choi

Proceedings Volume PC11934, PC1193403 (2022) https://doi.org/10.1117/12.2610549

KEYWORDS: Coherence imaging, Tissues, Tissue optics, Hemodynamics, Blood circulation, Scattering, Absorption, Oximetry, Spectroscopy, Silicon

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Proceedings Article | 2 March 2022 Presentation + Paper

Presentation + Paper

A 2x2-aperture 4-tap multi-modal tissue imager for multi-band SFDI and MELSCI

Yuto Shimada, Kazuki Takada, Hoang Son Nam, Kakeru Miyazaki, Keita Yasutomi, Shoji Kawahito, Christian Crouzet, Bernard Choi, Gordon Kennedy, Anthony Durkin, Keiichiro Kagawa

Proceedings Volume 11951, 1195107 (2022) https://doi.org/10.1117/12.2608397

KEYWORDS: Tissues, Imaging systems, CMOS sensors, Image sensors, Scattering, Tissue optics

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Proceedings Article | 2 March 2022 Presentation

Presentation

Three-dimensional visualization of cerebral microhemorrhages and surrounding microvasculature in hypertension

Danny Xie, Christian Crouzet, Krystal LoPresti, Yuke Wang, Christopher Robinson, David Cribbs, Mark Fisher, Bernard Choi

Proceedings Volume PC11966, PC1196606 (2022) https://doi.org/10.1117/12.2609926

KEYWORDS: Visualization, Brain, Tissues, Ischemic stroke, Tissue clearing, Neurons, Neuroimaging, MATLAB, Confocal microscopy, Capillaries

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SPIE Journal Paper | 19 April 2021 Open Access

Open Access

Simple methodology to visualize whole-brain microvasculature in three dimensions

Katiana Khouri, Danny Xie, Christian Crouzet, Adrian Bahani, David Cribbs, Mark Fisher, Bernard Choi

NPh, Vol. 8, Issue 02, 025004, (April 2021) https://doi.org/10.1117/12.10.1117/1.NPh.8.2.025004

KEYWORDS: Brain, Visualization, Luminescence, Neuroimaging, 3D image processing, Green fluorescent protein, Video, Tissues, Neurophotonics, Optical clearing

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SPIE Journal Paper | 8 April 2021 Open Access

Open Access

High-speed quantitative optical imaging of absolute metabolism in the rat cortex

Robert Wilson, Christian Crouzet, Mohammad Torabzadeh, Afsheen Bazrafkan, Niki Maki, Bruce Tromberg, Yama Akbari, Bernard Choi

NPh, Vol. 8, Issue 02, 025001, (April 2021) https://doi.org/10.1117/12.10.1117/1.NPh.8.2.025001

KEYWORDS: Brain, Mode conditioning cables, Optical imaging, Oxygen, Ischemia, Tissue optics, Tissues, Positron emission tomography, Optical properties, Neuroimaging

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Proceedings Article | 30 March 2021 Presentation

Presentation

A multi-aperture multi-tap image sensor for simultaneous multi-band SFDI and multi-exposure laser speckle contrast blood flow imaging

Keiichiro Kagawa, Gordon Kennedy, Adrien Ponticorvo, Iori Shibata, Keita Yasutomi, Shoji Kawahito, Jun Tanida, Christian Crouzet, Bernard Choi, Anthony Durkin

Proceedings Volume 11651, 116510H (2021) https://doi.org/10.1117/12.2578055

KEYWORDS: Image sensors, Blood circulation, Speckle, Modulators, Laser speckle contrast imaging, Imaging devices, Cameras, Video, Tissue optics, Spatial frequencies

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Proceedings Article | 5 March 2021 Presentation

Presentation

Welcome and Introduction to 2021 Photonics in Dermatology and Plastic Surgery Conference

Bernard Choi, Haishan Zeng

Proceedings Volume 11618, 1161802 (2021) https://doi.org/10.1117/12.2592874

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Proceedings Article | 5 March 2021 Presentation

Presentation

Contributions of diffuse and directed flow in turbid media to absolute measurements of tissue perfusion and oxygen consumption using laser speckle and spatial frequency domain imaging

Robert Wilson, Christian Crouzet, Afsheen Bazrafkan, Masih Rafi, Yama Akbari, Bernard Choi

Proceedings Volume 11629, 116290E (2021) https://doi.org/10.1117/12.2579039

KEYWORDS: Speckle, Oxygen, Laser tissue interaction, Tissues, Blood circulation, Tissue optics, Scattering, Positron emission tomography, Optical properties, Monte Carlo methods

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Proceedings Article | 5 March 2021 Presentation

Presentation

Spectroscopic based approach to identify and quantify cerebral microhemorrhages

Christian Crouzet, Gwangjin Jeong, Rachel Chae, Krystal LoPresti, Cody Dunn, Danny Xie, Chiagoziem Agu, Ane C. Nunes, Wei Ling Lau, Sehwan Kim, David Cribbs, Mark Fisher, Bernard Choi

Proceedings Volume 11647, 116470H (2021) https://doi.org/10.1117/12.2577039

KEYWORDS: Image segmentation, Spectroscopy, RGB color model, Mouse models, Cameras, Brain

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Proceedings Article | 5 March 2021 Presentation

Presentation

Three-dimensional quantification of cerebral vasculature in mouse brains with confocal microscopy

Danny Xie, Christian Crouzet, Katiana Khouri, Krystal LoPresti, Yuke Wang, Christopher Robinson, David Cribbs, Mark Fisher, Bernard Choi

Proceedings Volume 11649, 116490Z (2021) https://doi.org/10.1117/12.2578057

KEYWORDS: Image segmentation, Brain, Confocal microscopy, Blood vessels, Algorithm development, Optical clearing, Neurons, Luminescence, Kidney, Blood

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SPIE Journal Paper | 24 March 2018 Open Access

Open Access

Quantitative real-time optical imaging of the tissue metabolic rate of oxygen consumption

Michael Ghijsen, Griffin Lentsch, Sylvain Gioux, Matthew Brenner, Anthony Durkin, Bernard Choi, Bruce Tromberg

JBO, Vol. 23, Issue 03, 036013, (March 2018) https://doi.org/10.1117/12.10.1117/1.JBO.23.3.036013

KEYWORDS: Oxygen, Tissues, Mode conditioning cables, Tissue optics, Cyanide, Chromophores, Optical imaging, Blood circulation, Blood, Speckle

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SPIE Journal Paper | 15 March 2018 Open Access

Open Access

Correcting for motion artifact in handheld laser speckle images

Ben Lertsakdadet, Bruce Yang, Cody Dunn, Adrien Ponticorvo, Christian Crouzet, Nicole Bernal, Anthony Durkin, Bernard Choi

JBO, Vol. 23, Issue 03, 036006, (March 2018) https://doi.org/10.1117/12.10.1117/1.JBO.23.3.036006

KEYWORDS: Fermium, Frequency modulation, Speckle, Blood circulation, Data acquisition, Motion measurement, In vivo imaging, In vitro testing, Laser speckle imaging, Imaging systems

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Proceedings Article | 14 March 2018 Presentation

Presentation

Blood flow quantification of biopsied skin lesions using a laser speckle imaging dermatoscope (Conference Presentation)

Cody Dunn, Sean White, Manuel Valdebran, Kristen Kelly, Bernard Choi

Proceedings Volume 10467, 104670G (2018) https://doi.org/10.1117/12.2289390

KEYWORDS: Blood circulation, Skin, Laser speckle imaging, Speckle, Biopsy, Optical inspection, Image processing, Structural analysis, Laser development, Cameras

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Proceedings Article | 14 March 2018 Open Access

Open Access

Presentation

Global cerebral ischemia induces spatial propagation of cerebral blood flow during cardiac arrest and after resuscitation (Conference Presentation)

Christian Crouzet, Robert Wilson, Afsheen Bazrafkan, Juan Alcocer, Bruce Tromberg, Yama Akbari, Bernard Choi

Proceedings Volume 10481, 1048110 (2018) https://doi.org/10.1117/12.2291043

KEYWORDS: Brain, Ischemia, Cerebral blood flow, Speckle, Laser speckle imaging, Cranial windows

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SPIE Journal Paper | 26 December 2017 Open Access

Open Access

High-speed spatial frequency domain imaging of rat cortex detects dynamic optical and physiological properties following cardiac arrest and resuscitation

Robert Wilson, Christian Crouzet, Mohammad Torabzadeh, Afsheen Bazrafkan, Maryam Hosseini-Farahabadi, Babak Jamasian, Dishant Donga, Juan Alcocer, Shuhab Mohammed Zaher, Bernard Choi, Yama Akbari, Bruce Tromberg

NPh, Vol. 4, Issue 04, 045008, (December 2017) https://doi.org/10.1117/12.10.1117/1.NPh.4.4.045008

KEYWORDS: Scattering, Tissues, Brain, Tissue optics, Absorption, Cameras, Heart, Spatial frequencies, Oxygen, Light emitting diodes

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Proceedings Article | 6 February 2017 Presentation + Paper

Presentation + Paper

Quantitative assessment of graded burn wounds using a commercial and research grade laser speckle imaging (LSI) system

A. Ponticorvo, R. Rowland, B. Yang, B. Lertsakdadet, C. Crouzet, N. Bernal, B. Choi, A. Durkin

Proceedings Volume 10037, 100370I (2017) https://doi.org/10.1117/12.2253957

KEYWORDS: Imaging systems, Laser speckle imaging, Injuries, Speckle, Optical inspection, Doppler effect, Tissues, Analytical research, Photonics, Dermatology, Blood circulation, RGB color model, Wound healing, Surgery

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SPIE Journal Paper | 27 October 2016 Open Access

Open Access

Design and evaluation of a miniature laser speckle imaging device to assess gingival health

Caitlin Regan, Sean White, Bruce Yang, Thair Takesh, Jessica Ho, Cherie Wink, Petra Wilder-Smith, Bernard Choi

JBO, Vol. 21, Issue 10, 104002, (October 2016) https://doi.org/10.1117/12.10.1117/1.JBO.21.10.104002

KEYWORDS: Cameras, Speckle, Blood circulation, Imaging systems, In vivo imaging, Semiconductor lasers, Teeth, Laser speckle imaging, In vitro testing, Imaging devices

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SPIE Journal Paper | 31 August 2016 Open Access

Open Access

Handheld, point-of-care laser speckle imaging

Ryan Farraro, Omid Fathi, Bernard Choi

JBO, Vol. 21, Issue 09, 094001, (August 2016) https://doi.org/10.1117/12.10.1117/1.JBO.21.9.094001

KEYWORDS: Speckle, Blood circulation, Point-of-care devices, Laser speckle imaging, Tissues, In vivo imaging, In vitro testing, Cameras, Liquids, Surgery

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SPIE Journal Paper | 8 July 2016 Open Access

Open Access

Special Section Guest Editorial:Tissue and Blood Optical Clearing for Biomedical Applications

Dan Zhu, Bernard Choi, Elina Genina, Valery Tuchin

JBO, Vol. 21, Issue 08, 081201, (July 2016) https://doi.org/10.1117/12.10.1117/1.JBO.21.8.081201

KEYWORDS: Optical clearing, Biomedical optics, Optical coherence tomography, Tissue optics, Tissues, Blood, In vivo imaging, Visualization, Optical imaging, Skin

Proceedings Article | 27 April 2016 Presentation

Presentation

Quantitative long term measurements of burns in a rat model using spatial frequency domain imaging and laser speckle imaging (Conference Presentation)

Adrien Ponticorvo, Rebecca Rowland, Melissa Baldado, Gordon Kennedy, Rolf Saager, Bernard Choi, Anthony Durkin

Proceedings Volume 9711, 971102 (2016) https://doi.org/10.1117/12.2214080

KEYWORDS: Injuries, Laser speckle imaging, Wound healing, Speckle imaging, Optical inspection, Biopsy, Visualization, Inflammation, Scattering, Scatter measurement

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Proceedings Article | 27 April 2016 Presentation

Presentation

Modeling laser speckle imaging of perfusion in the skin (Conference Presentation)

Caitlin Regan, Carole Hayakawa, Bernard Choi

Proceedings Volume 9689, 96890D (2016) https://doi.org/10.1117/12.2212237

KEYWORDS: Monte Carlo methods, Skin, Speckle, Laser speckle imaging, Laser tissue interaction, Optical properties, Blood circulation, Blood vessels, Visualization, Vascular diseases

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Proceedings Article | 26 April 2016 Presentation

Presentation

Momentum transfer Monte Carlo model for the simulation of laser speckle contrast imaging (Conference Presentation)

Caitlin Regan, Carole Hayakawa, Bernard Choi

Proceedings Volume 9707, 970703 (2016) https://doi.org/10.1117/12.2212209

KEYWORDS: Monte Carlo methods, Tissues, Optical simulations, Speckle, Laser speckle contrast imaging, Laser speckle imaging, Optical properties, Tissue optics, Absorption, Light scattering

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Proceedings Article | 26 April 2016 Presentation

Presentation

Visualization of microhemorrhages with optical histology in mouse model of cerebral amyloid angiopathy (Conference Presentation)

Patrick Lo, Christian Crouzet, Vitaly Vasilevko, Bernard Choi

Proceedings Volume 9690, 969006 (2016) https://doi.org/10.1117/12.2213944

KEYWORDS: Visualization, Mouse models, Magnetic resonance imaging, Positron emission tomography, Brain, Medical laser equipment, In vivo imaging, Optical clearing, Optical imaging, Alzheimer's disease

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SPIE Journal Paper | 26 February 2016 Open Access

Open Access

Laser speckle imaging based on photothermally driven convection

Caitlin Regan, Bernard Choi

JBO, Vol. 21, Issue 02, 026011, (February 2016) https://doi.org/10.1117/12.10.1117/1.JBO.21.2.026011

KEYWORDS: Blood, Speckle, Convection, Laser speckle imaging, Pulsed laser operation, Particles, Temperature metrology, Scattering, Solids, Laser scattering

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SPIE Journal Paper | 12 October 2015 Open Access

Open Access

Differential pathlength factor informs evoked stimulus response in a mouse model of Alzheimer’s disease

Alexander Lin, Adrien Ponticorvo, Anthony Durkin, Vasan Venugopalan, Bernard Choi, Bruce Tromberg

NPh, Vol. 2, Issue 04, 045001, (October 2015) https://doi.org/10.1117/12.10.1117/1.NPh.2.4.045001

KEYWORDS: Brain, Optical properties, Oxygen, Mouse models, Scattering, Absorption, Hemodynamics, Neuroimaging, Near infrared, Reflectivity

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SPIE Journal Paper | 21 September 2015 Open Access

Open Access

Optical properties of mouse brain tissue after optical clearing with FocusClear™

Austin Moy, Bernard Capulong, Rolf Saager, Matthew Wiersma, Patrick Lo, Anthony Durkin, Bernard Choi

JBO, Vol. 20, Issue 09, 095010, (September 2015) https://doi.org/10.1117/12.10.1117/1.JBO.20.9.095010

KEYWORDS: Tissue optics, Optical clearing, Brain, Scattering, Tissues, Optical properties, Transmittance, Integrating spheres, Geometrical optics, Reflectivity

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SPIE Journal Paper | 21 October 2014 Open Access

Open Access

Spatial versus temporal laser speckle contrast analyses in the presence of static optical scatterers

Julio Ramirez-San-Juan, Caitlin Regan, Beatriz Coyotl-Ocelotl, Bernard Choi

JBO, Vol. 19, Issue 10, 106009, (October 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.10.106009

KEYWORDS: Speckle, Laser scattering, Teeth, Biomedical optics, Laser speckle contrast imaging, Scattering, Blood circulation, Biological research, Blood vessels, CCD cameras

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SPIE Journal Paper | 13 August 2014 Open Access

Open Access

Quantitative short-wave infrared multispectral imaging of in vivo tissue optical properties

Robert Wilson, Kyle Nadeau, Frank Jaworski, Rebecca Rowland, John Quan Nguyen, Christian Crouzet, Rolf Saager, Bernard Choi, Bruce Tromberg, Anthony Durkin

JBO, Vol. 19, Issue 08, 086011, (August 2014) https://doi.org/10.1117/12.10.1117/1.JBO.19.8.086011

KEYWORDS: Short wave infrared radiation, Scattering, Absorption, Tissue optics, Optical properties, In vivo imaging, Tissues, Multispectral imaging, Infrared imaging, Infrared radiation

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SPIE Journal Paper | 28 May 2014 Open Access

Open Access

Optical imaging in an Alzheimer’s mouse model reveals amyloid-β-dependent vascular impairment

Alexander Lin, Gangjun Liu, Nicholas Castello, James Yeh, Rombod Rahimian, Grace Lee, Victoria Tsay, Anthony Durkin, Bernard Choi, Frank LaFerla, Zhongping Chen, Kim Green, Bruce Tromberg

NPh, Vol. 1, Issue 01, 011005, (May 2014) https://doi.org/10.1117/12.10.1117/1.NPh.1.1.011005

KEYWORDS: Control systems, Brain, Optical imaging, Mouse models, Alzheimer's disease, Optical coherence tomography, In vivo imaging, Neuroimaging, Tissues, Proteins

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SPIE Journal Paper | 4 September 2013 Open Access

Open Access

Visible spatial frequency domain imaging with a digital light microprojector

Alexander Lin, Adrien Ponticorvo, Soren Konecky, Haotian Cui, Tyler Rice, Bernard Choi, Anthony Durkin, Bruce Tromberg

JBO, Vol. 18, Issue 09, 096007, (September 2013) https://doi.org/10.1117/12.10.1117/1.JBO.18.9.096007

KEYWORDS: Tissue optics, Scattering, Absorption, Spectrophotometry, Skull, Brain, Spatial frequencies, Projection systems, Optical properties, Cameras

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SPIE Journal Paper | 13 June 2013 Open Access

Open Access

Spatial frequency domain imaging of burn wounds in a preclinical model of graded burn severity

John Quan Nguyen, Christian Crouzet, Tuan Mai, Kathleen Riola, Daniel Uchitel, Lih-Huei Liaw, Nicole Bernal, Adrien Ponticorvo, Bernard Choi, Anthony Durkin

JBO, Vol. 18, Issue 06, 066010, (June 2013) https://doi.org/10.1117/12.10.1117/1.JBO.18.6.066010

KEYWORDS: Scattering, Injuries, Tissue optics, Tissues, Blood, Chromophores, Optical properties, Visualization, Skin, Oxygen

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Proceedings Article | 8 March 2013 Paper

Paper

Quantitative longitudinal measurement in a rat model of controlled burn severity using spatial frequency domain imaging

John Quan Nguyen, Christian Crouzet, Tuan Mai, Kathleen Riola, Daniel Uchitel, Lih-Huei Liaw, Nicole Bernal, Adrien Ponticorvo, Bernard Choi, Anthony Durkin

Proceedings Volume 8565, 85650S (2013) https://doi.org/10.1117/12.2004894

KEYWORDS: Oxygen, Tissues, Injuries, Chromophores, Optical microscopy, Skin, Optical properties, Optical imaging, Wound healing, Laser tissue interaction

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Proceedings Article | 13 February 2012 Paper

Paper

Implementation of an LED-based clinical spatial frequency domain imaging system

Amaan Mazhar, Seyed Sharif, Steve Saggese, Bernard Choi, David Cuccia, Anthony Durkin

Proceedings Volume 8254, 82540A (2012) https://doi.org/10.1117/12.909813

KEYWORDS: Optical properties, Absorption, Tissues, Light emitting diodes, Imaging systems, Scattering, Chromophores, Tissue optics, Skin, Oxygen

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Proceedings Article | 9 February 2012 Open Access

Open Access

Paper

Towards spatial frequency domain optical imaging of neurovascular coupling in a mouse model of Alzheimer's disease

Alexander Lin, Soren Konecky, Tyler Rice, Kim Green, Bernard Choi, Anthony Durkin, Bruce Tromberg

Proceedings Volume 8207, 82074U (2012) https://doi.org/10.1117/12.907557

KEYWORDS: Reflectivity, Mouse models, Cameras, Alzheimer's disease, Optical properties, Neurovascular coupling, Scattering, Optical imaging, Absorption, Tissue optics

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Proceedings Article | 30 January 2012 Paper

Paper

Intensity-based modified Doppler variance algorithm dedicated for phase instable optical coherence tomography systems

Gangjun Liu, Wangcun Jia, Danny Chou, Wenjuan Qi, Bernard Choi, Zhongping Chen

Proceedings Volume 8213, 821315 (2012) https://doi.org/10.1117/12.907151

KEYWORDS: Doppler tomography, Optical coherence tomography, Blood vessels, Blood circulation, Imaging systems, Doppler effect, In vivo imaging, Scanners, Mirrors, Spectroscopy

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SPIE Journal Paper | 1 January 2011 Open Access

Open Access

Real-time blood flow visualization using the graphics processing unit

Owen Yang, David Cuccia, Bernard Choi

JBO, Vol. 16, Issue 1, 016009, (January 2011) https://doi.org/10.1117/12.10.1117/1.3528610

KEYWORDS: Image processing, Speckle, Visualization, LabVIEW, Blood circulation, Image visualization, Video, Graphics processing units, Cameras, Video acceleration

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SPIE Journal Paper | 1 November 2010 Open Access

Open Access

Spectral Doppler optical coherence tomography imaging of localized ischemic stroke in a mouse model

Lingfeng Yu, Elaine Nguyen, Gangjun Liu, Bernard Choi, Zhongping Chen

JBO, Vol. 15, Issue 06, 066006, (November 2010) https://doi.org/10.1117/12.10.1117/1.3505016

KEYWORDS: Photodynamic therapy, Doppler tomography, Optical coherence tomography, Coherence imaging, Blood circulation, Optical imaging, Ischemic stroke, Resistance, Ischemia, Laser coagulation

Read Abstract +

Proceedings Article | 3 March 2010 Paper

Paper

Functional Doppler optical coherence tomography for cortical blood flow imaging

Lingfeng Yu, Gangjun Liu, Elaine Nguyen, Bernard Choi, Zhongping Chen

Proceedings Volume 7548, 75483Q (2010) https://doi.org/10.1117/12.842820

KEYWORDS: Doppler tomography, Optical coherence tomography, Blood circulation, Doppler effect, Brain mapping, Ischemic stroke, Tomography, Imaging systems, Resistance, Positron emission tomography

Read Abstract +

Proceedings Article | 26 February 2010 Paper

Paper

Effects of spatial and spectral frequencies on wide-field functional imaging (wifi) characterization of preclinical breast cancer models

Austin Moy, Jae Kim, Eva Y. H. Lee, Bernard Choi

Proceedings Volume 7573, 757309 (2010) https://doi.org/10.1117/12.842829

KEYWORDS: Tumors, Tissues, Tissue optics, Spatial frequencies, Breast cancer, Animal model studies, Tumor growth modeling, Monte Carlo methods, Instrument modeling, Functional imaging

Read Abstract +

Proceedings Article | 20 February 2010 Paper

Paper

Optical Doppler tomography and spectral Doppler imaging of localized ischemic stroke in a mouse model

Lingfeng Yu, Elaine Nguyen, Gangjun Liu, Bin Rao, Bernard Choi, Zhongping Chen

Proceedings Volume 7554, 75542E (2010) https://doi.org/10.1117/12.843016

KEYWORDS: Doppler tomography, Ischemic stroke, Optical coherence tomography, Blood circulation, Doppler effect, Mouse models, Arteries, Tomography, Resistance, Ultrasonography

Read Abstract +

SPIE Journal Paper | 1 January 2010 Open Access

Open Access

Magnetomotive laser speckle imaging

Jeehyun Kim, Junghwan Oh, Bernard Choi

JBO, Vol. 15, Issue 01, 011110, (January 2010) https://doi.org/10.1117/12.10.1117/1.3285612

KEYWORDS: Magnetism, Nanoparticles, Speckle, Blood circulation, Particles, Laser speckle imaging, Tissue optics, Iron, Optical coherence tomography, Capillaries

Read Abstract +

SPIE Journal Paper | 1 January 2010 Open Access

Open Access

Guest Editorial: Optical Methods in Vascular Biology and Medicine

Bernard Choi, Brett Bouma, Dai Fukumura, Rakesh Jain

JBO, Vol. 15, Issue 01, 011001, (January 2010) https://doi.org/10.1117/12.10.1117/1.3338696

KEYWORDS: Biomedical optics, Medicine, Biology, Optical coherence tomography, Photonics, Optical microscopy, Microscopy, Tumors, Animal model studies, Medical research

Proceedings Article | 24 February 2009 Paper

Paper

Revisiting optical clearing with dimethyl sulfoxide (DMSO): in vitro and in vivo studies

R. Anthony McClure, Charles Stoianovici, Sanjeev Karma, Bernard Choi

Proceedings Volume 7187, 718707 (2009) https://doi.org/10.1117/12.810888

KEYWORDS: Optical clearing, Scattering, In vivo imaging, Skin, In vitro testing, Tissue optics, Tissues, Biomedical optics, Luminescence, Light scattering

Read Abstract +

Proceedings Article | 24 February 2009 Open Access

Open Access

Paper

Brca1/p53 deficient mouse breast tumor hemodynamics during hyperoxic respiratory challenge monitored by a novel wide-field functional imaging (WiFI) system

Austin Moy, Jae Kim, Eva Y. H. Lee, Bruce Tromberg, Albert Cerussi, Bernard Choi

Proceedings Volume 7174, 71742L (2009) https://doi.org/10.1117/12.823745

KEYWORDS: Tumors, Blood, Oxygen, Tissues, Laser tissue interaction, Tissue optics, Breast, Functional imaging, Imaging systems, Reflectivity

Read Abstract +

Proceedings Article | 23 February 2009 Paper

Paper

Blood flow dynamics after laser therapy of port wine stain birthmarks

Yu-Chih Huang, Nadia Tran, E. Victor Ross, Peter Shumaker, J. Stuart Nelson, Kristen Kelly, Bernard Choi

Proceedings Volume 7161, 71610V (2009) https://doi.org/10.1117/12.811061

KEYWORDS: Laser therapeutics, Blood, Blood circulation, Skin, Speckle, Laser coagulation, Alexandrite lasers, Medical laser equipment, Surgery, Laser vision correction

Read Abstract +

Proceedings Article | 21 February 2009 Paper

Paper

Spectral Doppler imaging of micro-vasculature response to laser irradiation

Bin Rao, Wangcun Jia, Lingfeng Yu, Bernard Choi, Ronald Kurtz, J. Stuart Nelson, Zhongping Chen

Proceedings Volume 7168, 71681T (2009) https://doi.org/10.1117/12.809692

KEYWORDS: Doppler tomography, Laser irradiation, Optical coherence tomography, Blood circulation, Ultrasonography, Resistance, Laser speckle imaging, Doppler effect, In vivo imaging, Eye

Read Abstract +

Proceedings Article | 10 March 2008 Paper

Paper

Making CARS better

Max Zimmerley, Hyun Min Kim, Desiré Whitmore, Vishnu Vardhan Krishnamachari, Carole Hayakawa, Bernard Choi, Vasan Venugopalan, Eric Potma

Proceedings Volume 6853, 68530S (2008) https://doi.org/10.1117/12.778406

KEYWORDS: Scattering, Tissues, Signal detection, Microscopy, Raman spectroscopy, Skin, Tissue optics, Raman scattering, Molecules, Photons

Read Abstract +

SPIE Journal Paper | 1 March 2008 Open Access

Open Access

Enhancement of optical skin clearing efficacy using a microneedle roller

Jinhee Yoon, Taeyoon Son, Eung-Ho Choi, Bernard Choi, J. Stuart Nelson, Byungjo Jung

JBO, Vol. 13, Issue 02, 021103, (March 2008) https://doi.org/10.1117/12.10.1117/1.2907483

KEYWORDS: Skin, Optical clearing, Tissue optics, Modulation transfer functions, Light scattering, Biomedical optics, Biomedical engineering, Laser ablation, Polarization, Imaging systems

Read Abstract +

SPIE Journal Paper | 1 July 2006 Open Access

Open Access

Collagen solubility correlates with skin optical clearing

Jason Hirshburg, Bernard Choi, J. Nelson, Alvin Yeh

JBO, Vol. 11, Issue 04, 040501, (July 2006) https://doi.org/10.1117/12.10.1117/1.2220527

KEYWORDS: Collagen, Skin, Tissue optics, Optical clearing, Chemical analysis, Scattering, Tissues, Refractive index, Light scattering, In vitro testing

Read Abstract +

SPIE Journal Paper | 1 July 2006 Open Access

Open Access

Linear response range characterization and in vivo application of laser speckle imaging of blood flow dynamics

Bernard Choi, Julio Ramírez-San-Juan, Justin Lotfi, J. Nelson

JBO, Vol. 11, Issue 04, 041129, (July 2006) https://doi.org/10.1117/12.10.1117/1.2341196

KEYWORDS: Blood circulation, Speckle, In vivo imaging, Doppler tomography, Cameras, Skin, Animal model studies, Binary data, Laser speckle imaging, Medical laser equipment

Read Abstract +

Proceedings Article | 22 February 2006 Paper

Paper

Characterization and evaluation of a handheld AC-coupled pulsed photothermal radiometry system

Byungjo Jung, Chang-Seok Kim, Bernard Choi, J. Stuart Nelson

Proceedings Volume 6078, 60780M (2006) https://doi.org/10.1117/12.647103

KEYWORDS: Camera shutters, Temperature metrology, Skin, Calibration, Radiometry, In vivo imaging, Black bodies, Laser therapeutics, Infrared detectors, Pulsed laser operation

Read Abstract +

Proceedings Article | 20 February 2006 Paper

Paper

Comparison of Lorentzian- and Gaussian-based approaches for laser speckle imaging of blood flow dynamics

Julio Ramirez-San-Juan, J. Stuart Nelson, Bernard Choi

Proceedings Volume 6079, 607924 (2006) https://doi.org/10.1117/12.646891

KEYWORDS: Blood circulation, Speckle, Laser speckle imaging, Blood, In vivo imaging, Image processing, Photodynamic therapy, Doppler tomography, Scattering, Content addressable memory

Read Abstract +

Proceedings Article | 25 April 2005 Paper

Paper

Clinical feasibility of various optical instruments for quantitative evaluation of pulsed-dye laser treatment of port wine stain skin

Chang-Seok Kim, Byungjo Jung, Bernard Choi, Wim Verkruysse, Rong Zhang, John Nelson

Proceedings Volume 5686, (2005) https://doi.org/10.1117/12.589706

KEYWORDS: Skin, In vivo imaging, Reflectivity, Optical spheres, In vitro testing, Diffuse reflectance spectroscopy, Laser therapeutics, Color difference, Visualization, Spectrometers

Read Abstract +

Proceedings Article | 25 April 2005 Paper

Paper

Characterization of a laser speckle imaging instrument for monitoring skin blood flow dynamics

Bernard Choi, Julio Ramirez-San-Juan, John Nelson

Proceedings Volume 5686, (2005) https://doi.org/10.1117/12.589147

KEYWORDS: Blood circulation, Speckle, Laser speckle imaging, Skin, Data modeling, Blood, In vitro testing, Doppler tomography, Photodynamic therapy, Laser therapeutics

Read Abstract +

Proceedings Article | 25 April 2005 Paper

Paper

Evaluation of vascular effects after photodynamic and photothermal therapies using benzoporphyrin derivative monoacid ring A on a rodent dorsal skinfold model

Tia Smith, Bernard Choi, Julio Ramirez-San-Juan, John Nelson, Kristen Kelly

Proceedings Volume 5686, (2005) https://doi.org/10.1117/12.589466

KEYWORDS: Photodynamic therapy, Skin, Laser irradiation, Therapeutics, Blood vessels, Injuries, Laser speckle imaging, Animal model studies, Medical laser equipment, Continuous wave operation

Read Abstract +

Proceedings Article | 25 April 2005 Paper

Paper

Effects of lens housing temperature on subsurface temperature profiling using pulsed photothermal radiometry

Byungjo Jung, Bernard Choi, Boris Majaron, John Nelson

Proceedings Volume 5686, (2005) https://doi.org/10.1117/12.589409

KEYWORDS: Temperature metrology, Calibration, Infrared cameras, Black bodies, Infrared imaging, Profiling, Radiometry, Imaging systems, Tissues, Control systems

Read Abstract +

Proceedings Article | 25 April 2005 Paper

Paper

Effects of relative humidity on laser light transmittance during cryogen spray cooling of in vitro skin phantoms

Julio Ramirez-San-Juan, Bernard Choi, Walfre Franco, John Nelson, Guillermo Aguilar

Proceedings Volume 5686, (2005) https://doi.org/10.1117/12.591197

KEYWORDS: Cryogenics, Humidity, Transmittance, Skin, Glasses, Signal attenuation, Light scattering, Laser scattering, Scattering, Absorption

Read Abstract +

Proceedings Article | 15 April 2005 Paper

Paper

Measuring the effects of topically applied skin optical clearing agents and modeling the effects and consequences for laser therapies

Wim Verkruysse, Misbah Khan, Bernard Choi, Lars Svaasand, J. Stuart Nelson

Proceedings Volume 5695, (2005) https://doi.org/10.1117/12.591421

KEYWORDS: Skin, Scattering, Optical coherence tomography, Laser scattering, Tissue optics, Reflectors, Laser therapeutics, Optical clearing, Light scattering, Diffusion

Read Abstract +

Proceedings Article | 4 April 2005 Paper

Paper

Input polarization-independent multi-channel switching using cascaded long-period fiber grating and polarization-maintaining fiber

Chang-Seok Kim, Young-Geun Han, Bernard Choi, John Nelson, Jin Kang

Proceedings Volume 5723, (2005) https://doi.org/10.1117/12.589710

KEYWORDS: Optical filters, Polarization, Cladding, Switching, Single mode fibers, Polarization maintaining fibers, Reflection, Birefringence, Acousto-optics, Interferometers

Read Abstract +

SPIE Journal Paper | 1 March 2005 Open Access

Open Access

Determination of human skin optical properties from spectrophotometric measurements based on optimization by genetic algorithms

Rong Zhang, Wim Verkruysse, Bernard Choi, John Viator, Byungjo Jung, Lars Svaasand, Guillermo Aguilar, John Nelson

JBO, Vol. 10, Issue 02, 024030, (March 2005) https://doi.org/10.1117/12.10.1117/1.1891147

KEYWORDS: Skin, Blood, Optical properties, Diffusion, Reflectivity, Tissue optics, Genetic algorithms, Absorption, Blood vessels, Monte Carlo methods

Read Abstract +

SPIE Journal Paper | 1 March 2005 Open Access

Open Access

Determination of optimal view angles for quantitative facial image analysis

Byungjo Jung, Bernard Choi, Yongjin Shin, Anthony Durkin, John Nelson

JBO, Vol. 10, Issue 02, 024002, (March 2005) https://doi.org/10.1117/12.10.1117/1.1895987

KEYWORDS: Skin, Head, Diffuse reflectance spectroscopy, Image analysis, Human subjects, Imaging systems, RGB color model, Cameras, Reflectivity, Image acquisition

Read Abstract +

Proceedings Article | 13 July 2004 Paper

Paper

Effects of curvature and view angle on quantitative imaging of erythema and melanin content in facial port wine stain skin

Byungjo Jung, Bernard Choi, Yongjin Shin, Anthony Durkin, J. Nelson

Proceedings Volume 5312, (2004) https://doi.org/10.1117/12.528069

KEYWORDS: Head, Skin, RGB color model, Imaging systems, Diffuse reflectance spectroscopy, Reflectivity, Laser therapeutics, Image analysis, Cameras, Image acquisition

Read Abstract +

Proceedings Article | 1 July 2004 Paper

Paper

Evaluation of photothermal tomography for imaging the microvasculature of human skin

Bernard Choi, Boris Majaron, John Nelson

Proceedings Volume 5318, (2004) https://doi.org/10.1117/12.529318

KEYWORDS: Blood vessels, Skin, Tomography, Chromophores, Infrared radiation, 3D image processing, Infrared imaging, Deconvolution, 3D modeling, Computer simulations

Read Abstract +

Proceedings Article | 1 July 2004 Paper

Paper

Selection of optimal infrared detector for pulsed photothermal profiling of vascular lesions

Boris Majaron, Matija Milanic, Bernard Choi, John Nelson

Proceedings Volume 5318, (2004) https://doi.org/10.1117/12.540973

KEYWORDS: Sensors, Signal to noise ratio, Absorption, Profiling, Skin, Interference (communication), Infrared detectors, Signal detection, Infrared sensors, Infrared radiation

Read Abstract +

SPIE Journal Paper | 1 March 2004 Open Access

Open Access

Computational model to evaluate port wine stain depth profiling using pulsed photothermal radiometry

Bernard Choi, Boris Majaron, John Nelson

JBO, Vol. 9, Issue 02, (March 2004) https://doi.org/10.1117/12.10.1117/1.1646173

KEYWORDS: Skin, Blood, Absorption, Blood vessels, Monte Carlo methods, Profiling, Tissue optics, Temperature metrology, Laser therapeutics, Signal to noise ratio

SPIE Journal Paper | 1 March 2004 Open Access

Open Access

Use of optical coherence tomography to monitor biological tissue freezing during cryosurgery

Bernard Choi, Thomas Milner, Jeehyun Kim, Jared Goodman, Gracie Vargas, Guillermo Aguilar, John Nelson

JBO, Vol. 9, Issue 02, (March 2004) https://doi.org/10.1117/12.10.1117/1.1648647

KEYWORDS: Optical coherence tomography, Skin, Liquids, Tissue optics, Nitrogen, Water, In vivo imaging, Reflectivity, Tissues, Scattering

Proceedings Article | 12 September 2003 Paper

Paper

Theoretical evaluation of pulsed photothermal radiometry (PPTR) for depth profiling of port wine stain skin

Bernard Choi, Boris Majaron, J. Nelson

Proceedings Volume 4949, (2003) https://doi.org/10.1117/12.476145

KEYWORDS: Skin, Profiling, Laser therapeutics, Radiometry, Blood, Reconstruction algorithms, Tissue optics, Blood vessels, Pulsed laser operation, Monte Carlo methods

Read Abstract +

Proceedings Article | 12 September 2003 Paper

Paper

Temperature distribution in port wine stain following pulsed irradiation by a dual-wavelength Nd:YAG laser

Boris Majaron, Bernard Choi, J. Nelson

Proceedings Volume 4949, (2003) https://doi.org/10.1117/12.476148

KEYWORDS: Pulsed laser operation, Skin, Infrared cameras, Temperature metrology, Laser therapeutics, Ferroelectric materials, Solids, Laser systems engineering, Absorption, Laser safety

Read Abstract +

Proceedings Article | 1 August 2003 Paper

Paper

In vivo results using photothermal tomography for imaging cutaneous blood vessels

Bernard Choi, Boris Majaron, Gracie Vargas, Byungjo Jung, Oliver Stumpp, Nicole Kang, Kristen Kelly, Ashley Welch, J. Stuart Nelson

Proceedings Volume 5047, (2003) https://doi.org/10.1117/12.484140

KEYWORDS: Skin, Blood vessels, Infrared imaging, Infrared radiation, Laser irradiation, Infrared cameras, Absorption, In vivo imaging, Tomography, Laser therapeutics

Read Abstract +

Proceedings Article | 1 July 2003 Paper

Paper

Photoacoustic measurement of epidermal melanin

John Viator, Lars Svaasand, Guillermo Aguilar, Bernard Choi, J. Stuart Nelson

Proceedings Volume 4960, (2003) https://doi.org/10.1117/12.477648

KEYWORDS: Photoacoustic spectroscopy, Skin, Acoustics, Tissue optics, Human subjects, Laser therapeutics, Absorption, Pulsed laser operation, Optical fibers, Phototherapy

Read Abstract +

Proceedings Article | 10 June 2003 Paper

Paper

Experimental study of multiple-intermittent cryogen spurts and laser pulses for the treatment of port wine stain birthmarks

Guillermo Aguilar, Bernard Choi, John Viator, Dan Andersen, J. Stuart Nelson

Proceedings Volume 4954, (2003) https://doi.org/10.1117/12.476536

KEYWORDS: Skin, Cryogenics, Pulsed laser operation, Temperature metrology, Absorption, Infrared cameras, Solids, Transmittance, Laser therapeutics, Data modeling

Read Abstract +

Proceedings Article | 17 June 2002 Paper

Paper

Dynamic measurements of laser light attenuation by cryogen film and frost formation

Bernard Choi, Guillermo Aguilar, Gracie Vargas, Ashley Welch, J. Stuart Nelson

Proceedings Volume 4609, (2002) https://doi.org/10.1117/12.432051

KEYWORDS: Cryogenics, Transmittance, Skin, Glasses, Light scattering, Pulsed laser operation, Optical testing, Sensors, Signal attenuation, Liquids

Read Abstract +

Proceedings Article | 10 June 2002 Paper

Paper

Design limitations of a photoacoustic probe for port wine stain depth determination

John Viator, Gigi Au, Bernard Choi, J. Stuart Nelson

Proceedings Volume 4618, (2002) https://doi.org/10.1117/12.469861

KEYWORDS: Photoacoustic spectroscopy, Skin, Tissue optics, Acoustics, Absorption, Optical fibers, Signal detection, Ferroelectric polymers, Sensors, Optical properties

Read Abstract +

Proceedings Article | 21 May 2001 Paper

Paper

Jet impingement modeling of cryogen spray cooling: analysis of 2D cryogen temperature distribution

Bernard Choi, Ashley Welch

Proceedings Volume 4244, (2001) https://doi.org/10.1117/12.427836

KEYWORDS: Cryogenics, Temperature metrology, Infrared imaging, Aluminum, Infrared radiation, Skin, Thermal modeling, Tissues, Black bodies, Natural surfaces

Read Abstract +

Proceedings Article | 13 June 2000 Paper

Paper

Modeling infrared temperature measurements: comparison of experimental results with simulations

Bernard Choi, John Pearce, Ashley Welch

Proceedings Volume 3914, (2000) https://doi.org/10.1117/12.388021

KEYWORDS: Temperature metrology, Natural surfaces, Thermal modeling, Laser tissue interaction, Thermography, Absorption, Sensors, Infrared radiation, Tissues, Cameras

Read Abstract +

Proceedings Article | 17 May 2000 Paper

Paper

Simultaneous video and thermal imaging of cryogen spray cooling

Bernard Choi, Ashley Welch

Proceedings Volume 3907, (2000) https://doi.org/10.1117/12.386257

KEYWORDS: Cryogenics, Thermography, Skin, Video, Thermal modeling, Temperature metrology, In vivo imaging, CCD cameras, Convection, Tissues

Read Abstract +

Proceedings Article | 28 April 2000 Paper

Paper

Free-electron laser tissue-soldering in vitro with an albumin solder

Brian Sorg, Bernard Choi, Karen McNally-Heintzelman, E. Duco Jansen, Ashley Welch

Proceedings Volume 3925, (2000) https://doi.org/10.1117/12.384257

KEYWORDS: Absorption, Free electron lasers, Laser welding, Laser tissue interaction, Tissues, Chromophores, Natural surfaces, In vitro testing, Infrared radiation, Proteins

Read Abstract +

Proceedings Article | 28 April 2000 Paper

Paper

Influence of optical absorption on urinary calculus threshold fluence and ablation efficiency during infrared laser ablation

Kin Foong Chan, Daniel Hammer, Bernard Choi, Gracie Vargas, Brian Sorg, T. Joshua Pfefer, Joel Teichman, H. Stan McGuff, Hans Pratisto, E. Duco Jansen, Ashley Welch

Proceedings Volume 3925, (2000) https://doi.org/10.1117/12.384253

KEYWORDS: Laser ablation, Absorption, Calculi, Laser damage threshold, Tissue optics, Calculus, Absorbance, Hard tissue optics, Free electron lasers, Infrared radiation

Read Abstract +

Proceedings Article | 25 June 1999 Paper

Paper

Step and flash imprint lithography: a new approach to high-resolution patterning

Matthew Colburn, Stephen Johnson, Michael Stewart, S. Damle, Todd Bailey, Bernard Choi, M. Wedlake, Timothy Michaelson, S. Sreenivasan, John Ekerdt, C. Grant Willson

Proceedings Volume 3676, (1999) https://doi.org/10.1117/12.351155

KEYWORDS: Etching, Semiconducting wafers, Lithography, Silicon, Photomasks, Quartz, Ultraviolet radiation, Liquids, Interfaces, Chromium

Read Abstract +

Proceedings Article | 22 June 1999 Paper

Paper

Temperature measurements during laser skin welding

Nathaniel Fried, Bernard Choi, Ashley Welch, Joseph Walsh

Proceedings Volume 3590, (1999) https://doi.org/10.1117/12.350953

KEYWORDS: Temperature metrology, In vitro testing, Tissues, Skin, Laser welding, In vivo imaging, Natural surfaces, Laser damage threshold, Cameras, Laser tissue interaction

Read Abstract +

Proceedings Article | 22 June 1999 Paper

Paper

Mechanisms of laser-induced thermal coagulation of whole blood in vitro

T. Joshua Pfefer, Bernard Choi, Gracie Vargas, Karen McNally-Heintzelman, Ashley Welch

Proceedings Volume 3590, (1999) https://doi.org/10.1117/12.350970

KEYWORDS: Blood, Pulsed laser operation, Temperature metrology, Laser damage threshold, Optical coherence tomography, Scattering, In vitro testing, Laser scattering, Cameras, Skin

Read Abstract +

Proceedings Article | 30 April 1999 Paper

Paper

Assessing vessel damage with color Doppler optical coherence tomography following irradiations with cooling

Gracie Vargas, Jennifer Barton, Bernard Choi, Joseph Izatt, Ashley Welch

Proceedings Volume 3598, (1999) https://doi.org/10.1117/12.347488

KEYWORDS: Skin, Blood vessels, Cryogenics, Temperature metrology, Laser irradiation, Optical coherence tomography, Ferroelectric materials, Doppler tomography, Blood circulation, Pulsed laser operation

Read Abstract +

Proceedings Article | 1 July 1998 Paper

Paper

Infrared imaging of CO2 laser ablation: implications for laser skin resurfacing

Bernard Choi, Jennifer Barton, Eric Chan, Sharon Thomsen, Ashley Welch

Proceedings Volume 3245, (1998) https://doi.org/10.1117/12.312306

KEYWORDS: Skin, Tissues, Temperature metrology, Carbon dioxide lasers, Laser ablation, Combustion, Natural surfaces, Cameras, In vivo imaging, Laser tissue interaction

Read Abstract +

Proceedings Article | 22 May 1997 Paper

Paper

Infrared imaging of CO2 laser resurfacing

Ashley Welch, Eric Chan, Jennifer Barton, Bernard Choi, Sharon Thomsen

Proceedings Volume 2970, (1997) https://doi.org/10.1117/12.275061

KEYWORDS: Temperature metrology, Pulsed laser operation, Carbon dioxide lasers, Skin, Cameras, Laser ablation, Tissues, Picosecond phenomena, Infrared imaging, Laser tissue interaction

Read Abstract +

Showing 5 of 95 publications

Proceedings Volume Editor (18)

SPIE Conference Volume | 14 April 2023

Photonics in Dermatology and Plastic Surgery 2023

SPIE Conference Volume | 21 March 2022

Photonics in Dermatology and Plastic Surgery 2022

SPIE Conference Volume | 22 April 2021

Photonics in Dermatology and Plastic Surgery 2021

SPIE Conference Volume | 6 March 2020

Photonics in Dermatology and Plastic Surgery 2020

SPIE Conference Volume | 7 June 2019

Photonics in Dermatology and Plastic Surgery 2019

Showing 5 of 18 publications

Conference Committee Involvement (32)

Neural Imaging and Sensing 2025

27 January 2025 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery 2025

25 January 2025 | San Francisco, California, United States

Clinical and Translational Neurophotonics 2025

25 January 2025 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery 2024

27 January 2024 | San Francisco, California, United States

Neural Imaging and Sensing 2024

27 January 2024 | San Francisco, California, United States

Neural Imaging and Sensing 2023

30 January 2023 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery 2023

28 January 2023 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery 2022

22 January 2022 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery 2021

6 March 2021 | Online Only, California, United States

Photonics in Dermatology and Plastic Surgery 2020

1 February 2020 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery 2019

2 February 2019 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery 2018

27 January 2018 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

28 January 2017 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

13 February 2016 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

7 February 2015 | San Francisco, California, United States

Biomedical Applications of Light Scattering VIII

1 February 2014 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

1 February 2014 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

2 February 2013 | San Francisco, California, United States

Biomedical Applications of Light Scattering VII

2 February 2013 | San Francisco, California, United States

Biomedical Applications of Light Scattering VI

21 January 2012 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

21 January 2012 | San Francisco, California, United States

Biomedical Applications of Light Scattering V

22 January 2011 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

22 January 2011 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

23 January 2010 | San Francisco, California, United States

Biomedical Applications of Light Scattering IV

23 January 2010 | San Francisco, California, United States

Photonics in Dermatology and Plastic Surgery

24 January 2009 | San Jose, California, United States

Biomedical Applications of Light Scattering III

24 January 2009 | San Jose, California, United States

Complex Dynamics and Fluctuations in Biomedical Photonics V

19 January 2008 | San Jose, California, United States

Photonics in Dermatology and Plastic Surgery

19 January 2008 | San Jose, California, United States

Complex Dynamics and Fluctuations in Biomedical Photonics IV

20 January 2007 | San Jose, California, United States

Photonics in Dermatology and Plastic Surgery

20 January 2007 | San Jose, California, United States

Photonics in Dermatology and Plastic Surgery

21 January 2006 | San Jose, California, United States

Showing 5 of 32 Conference Committees

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