Dr. Alex J. Walsh Profile

Dr. Alex J. Walsh

Assistant Professor at Texas A&M Univ

SPIE Involvement:

Education and Outreach Committee | Conference Program Committee | Conference Chair | Conference Co-Chair | Editorial Board Member: Biophotonics Discovery | Author | Editor | Student Chapter Advisor

Publications (39)

SPIE Journal Paper | 13 June 2024 Open Access

Open Access

Comparison of polystyrene and hydrogel microcarriers for optical imaging of adherent cells

Oscar Benavides, Berkley White, Holly Gibbs, Roland Kaunas, Carl Gregory, Kristen Maitland, Alex Walsh

JBO, Vol. 29, Issue S2, S22708, (June 2024) https://doi.org/10.1117/12.10.1117/1.JBO.29.S2.S22708

KEYWORDS: Polystyrene, Visualization, Fluorescence intensity, Simulations, Hydrogels, Fluorescence, Elasticity, Optical surfaces, Mie scattering, Wavefront errors

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Proceedings Article | 13 March 2024 Presentation

Presentation

Multiphoton microscopy of A. phagocytophilum infection

Alex Walsh, Vidhya Shree Ravi, Adela Oliva Chavez

Proceedings Volume PC12847, PC128470M (2024) https://doi.org/10.1117/12.3003301

KEYWORDS: Skin, Multiphoton microscopy, Collagen, Bacteria, Multiphoton fluorescence microscopy, Diseases and disorders, Autofluorescence, Tissues, Second harmonic generation, Microscopy

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Proceedings Article | 13 March 2024 Presentation

Presentation

Comparison of microcarrier composition for optical imaging of adherent cells in bioreactor-microcarrier cell cultures

Oscar Benavides, Alex Walsh

Proceedings Volume PC12840, PC128400J (2024) https://doi.org/10.1117/12.3001663

KEYWORDS: Visualization, Polystyrene, Optical imaging, Mie scattering, Simulations, Microscopy, Image visualization, 3D imaging standards, Tomography, Therapeutics

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Proceedings Article | 13 March 2024 Presentation

Presentation

PLUTO: a polarized light-sheet microscopy and tomography system for versatile multi-scale and high-throughput cellular resolution imaging

Oscar Benavides, Alex Walsh

Proceedings Volume PC12827, PC128270Q (2024) https://doi.org/10.1117/12.3001188

KEYWORDS: Imaging systems, Biological imaging, Image resolution, Tomography, Polarized microscopy, Pluto, Biological samples, Stem cells, Optical imaging, Microscopy

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Proceedings Article | 13 March 2024 Presentation

Presentation

Machine learning to advance fluorescence lifetime imaging analysis and applications

Alex Walsh, Linghao Hu, Blanche ter Hofstede, Daniela De Hoyos Canales

Proceedings Volume PC12833, PC128330H (2024) https://doi.org/10.1117/12.3009339

KEYWORDS: Machine learning, Fluorescence lifetime imaging, Fluorescence, Nicotinamide adenine dinucleotide, Mode conditioning cables, Fluorophores, Time metrology, Molecules, Image analysis, Ground state

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Proceedings Article | 12 March 2024 Poster + Paper

Poster + Paper

Autofluorescence intensity imaging for studying mitochondrial dynamics

Blanche ter Hofstede, Amanda Galloway, Alex Walsh

Proceedings Volume 12854, 128540V (2024) https://doi.org/10.1117/12.3003064

KEYWORDS: Mitochondria, Nicotinamide adenine dinucleotide, Cyanide, Autofluorescence imaging, Emission wavelengths, Breast cancer, Autofluorescence

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Proceedings Article | 12 March 2024 Presentation + Paper

Presentation + Paper

Characterization of a multispectral visible imaging system for monitoring perfusion changes in dogs under anesthesia

Elizabeth Bullard, Oscar Benavides, Erin Stout, Meghan Watt, Vanna Dickerson-Bagley, Alex Walsh

Proceedings Volume 12854, 1285406 (2024) https://doi.org/10.1117/12.3000088

KEYWORDS: Reflectivity, Imaging systems, Skin, Multispectral imaging, Tissues, Light sources and illumination, Animals, Image processing, Cameras, Tunable filters

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Proceedings Article | 16 March 2023 Presentation + Paper

Presentation + Paper

Identifying cancer cell metabolic states in autofluorescence lifetime images with machine learning

Linghao Hu, Alex Walsh

Proceedings Volume 12391, 1239104 (2023) https://doi.org/10.1117/12.2648436

KEYWORDS: Cancer, Autofluorescence, Fluorescence, Nicotinamide adenine dinucleotide, Machine learning, Education and training, Convolutional neural networks, Mode conditioning cables, Performance modeling, Fluorescence intensity

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Proceedings Article | 15 March 2023 Presentation

Presentation

Quantitative analysis of label-free fluorescence lifetime images for single cell measurements of metabolism (Conference Presentation)

Alex Walsh, Linghao Hu, Nianchao Wang, Addison Threet

Proceedings Volume PC12384, PC1238406 (2023) https://doi.org/10.1117/12.2655956

KEYWORDS: Mode conditioning cables, Luminescence, Image segmentation, Quantitative analysis, Cancer, Algorithm development, Therapeutics, Resistance, Pathology, Oxygen

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Proceedings Article | 14 March 2023 Presentation

Presentation

Metabolic perturbations of macrophages on engineered collagen scaffolds with label-free fluorescence lifetime imaging (Conference Presentation)

Linghao Hu, Dhavan Sharma, Feng Zhao, Alex Walsh

Proceedings Volume 12380, 123800G (2023) https://doi.org/10.1117/12.2650468

KEYWORDS: Fluorescence lifetime imaging, Luminescence, Collagen, Tissues, Veins, Stem cells, Skin, Proteins, Oxygen, Multiphoton microscopy

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Proceedings Article | 7 February 2023 Presentation

Presentation

Infrared light effects on coenzyme binding and cellular metabolism

Jocelyn Martinez, Anna Theodossiou, Alex Walsh

Proceedings Volume PC11958, PC1195807 (2023) https://doi.org/10.1117/12.2608239

KEYWORDS: Infrared radiation, Mode conditioning cables, Infrared imaging, Short wave infrared radiation, Thermal modeling, Neurons, Infrared technology, Thermography, Nerve, Ions

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Proceedings Article | 7 March 2022 Presentation

Presentation

Single-cell analysis of autofluorescence lifetime images

Alex Walsh, Elizabeth Cardona, Samantha Morganti, Nianchao Wang, Linghao Hu, Addison Threet

Proceedings Volume PC11965, PC119650H (2022) https://doi.org/10.1117/12.2609806

KEYWORDS: Multiphoton fluorescence microscopy, Tumors, Image analysis, Breast cancer, Mode conditioning cables, Machine learning, Image segmentation, Image processing algorithms and systems, Data modeling, Stem cells

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Proceedings Article | 7 March 2022 Poster + Presentation

Poster + Presentation

Multiphoton microscopy to characterize macrophage function and collagen alignment

Linghao Hu, Dhavan Sharma, Te-An Chen, Feng Zhao, Alex Walsh

Proceedings Volume PC11965, PC119650K (2022) https://doi.org/10.1117/12.2619396

KEYWORDS: Multiphoton microscopy, Collagen, Luminescence, Skin, Fluorescence lifetime imaging, Wound healing, Tissues, Second-harmonic generation, Oxidation, Mode conditioning cables

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Proceedings Article | 2 March 2022 Presentation + Paper

Presentation + Paper

Modeling key metabolic pathways of cancer cells using label-free fluorescence lifetime imaging

Linghao Hu, Alex Walsh

Proceedings Volume 11972, 1197206 (2022) https://doi.org/10.1117/12.2608760

KEYWORDS: Luminescence, Cancer, Fluorescence lifetime imaging, Glucose, Molecules, Cyanide, Tumor growth modeling, Multiphoton fluorescence microscopy

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Proceedings Article | 2 March 2022 Presentation

Presentation

High speed autofluorescence imaging of the effects of short pulses of infrared light

Alex Walsh, Jocelyn Martinez, Anna Theodossiou

Proceedings Volume PC11971, PC119710B (2022) https://doi.org/10.1117/12.2613561

KEYWORDS: Infrared radiation, Infrared imaging, Auto-fluorescence imaging, Short wave infrared radiation, Thermal modeling, Neurons, Mode conditioning cables, Microscopy, Machine learning, Luminescence

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SPIE Journal Paper | 25 May 2021 Open Access

Open Access

Extracellular pH affects the fluorescence lifetimes of metabolic co-factors

Rebecca Schmitz, Kelsey Tweed, Christine Walsh, Alex Walsh, Melissa Skala

JBO, Vol. 26, Issue 05, 056502, (May 2021) https://doi.org/10.1117/12.10.1117/1.JBO.26.5.056502

KEYWORDS: Luminescence, Fluorescence lifetime imaging, Calibration, Mode conditioning cables, Molecules, Tumors, Tissues, Image segmentation, Carbon monoxide, Breast cancer

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Proceedings Article | 5 March 2021 Presentation + Paper

Presentation + Paper

Optical imaging of zebrafish xenograft tumors for a high throughput drugs screen

Uyen Nguyen, Johanna Webb, Rebecca Schmitz, Kelsey Tweed, Anna Huttenlocher, Melissa Skala, Alex Walsh

Proceedings Volume 11622, 116220E (2021) https://doi.org/10.1117/12.2577637

KEYWORDS: Tumors, Optical imaging, Breast cancer, Luminescence, Image resolution, Cancer, Toxicity, Tissues, Oncology

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Proceedings Article | 5 March 2021 Presentation + Paper

Presentation + Paper

Classification of T cell metabolism from autofluorescence imaging features

Linghao Hu, Nianchao Wang, Alex Walsh

Proceedings Volume 11647, 1164707 (2021) https://doi.org/10.1117/12.2577004

KEYWORDS: Mode conditioning cables, Luminescence, Auto-fluorescence imaging, Signal detection, Feature extraction

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Proceedings Article | 5 March 2021 Presentation

Presentation

Fluorescence lifetime imaging of metabolic co-enzymes to determine cell type and function

Alex Walsh, Linghao Hu, Elizabeth Cardona, Nianchao Wang, Jocelyn Martinez, Uyen Nguyen, Naman Bala

Proceedings Volume 11648, 116480K (2021) https://doi.org/10.1117/12.2577866

KEYWORDS: Fluorescence lifetime imaging, Luminescence, Tumors, Tissues, Multiphoton fluorescence microscopy, Mode conditioning cables, Image segmentation, Image classification, Image analysis, Cancer

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Proceedings Article | 9 March 2020 Presentation

Presentation

Label-free classification of T cell activation (Conference Presentation)

Melissa Skala, Alex Walsh, Kelsey Tweed, Katie Mueller, Isabel Jones, Steven Trier, Krishanu Saha

Proceedings Volume 11244, 112440A (2020) https://doi.org/10.1117/12.2546366

KEYWORDS: Nondestructive evaluation, Auto-fluorescence imaging, Optical imaging, Mode conditioning cables, Machine learning, Blood, Multiphoton fluorescence microscopy, Microscopes, Feature selection, Cancer

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Proceedings Article | 4 March 2019 Presentation + Paper

Presentation + Paper

Zebrafish xenograft breast cancer models for high-throughput drug response screening

Rebecca Schmitz, Alex Walsh, Kelsey Tweed, Steve Trier, Anna Huttenlocher, Melissa Skala

Proceedings Volume 10888, 1088804 (2019) https://doi.org/10.1117/12.2513688

KEYWORDS: Tumors, Breast cancer, Tumor growth modeling, Luminescence, Cancer, In vivo imaging, Fluorescence lifetime imaging, Oncology, Statistical modeling, Statistical analysis

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Proceedings Article | 22 February 2019 Presentation + Paper

Presentation + Paper

Effects of pH on FAD autofluorescence lifetimes

Rebecca Schmitz, Christine Walsh, Alex Walsh, Melissa Skala

Proceedings Volume 10882, 108820C (2019) https://doi.org/10.1117/12.2513482

KEYWORDS: Fluorescence lifetime imaging, Cancer, Multiphoton fluorescence microscopy

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Proceedings Article | 15 August 2017 Presentation

Presentation

Predicting patient response to therapy in pancreatic and breast cancer using optical metabolic imaging (Conference Presentation)

Joe Sharick, Alexandra Walsh, Melinda Sanders, Mark Kelley, Ingrid Meszoely, Mary Hooks, Alexander Parikh, Melissa Skala

Proceedings Volume 10068, 1006806 (2017) https://doi.org/10.1117/12.2253431

KEYWORDS: Breast, Breast cancer, Optical imaging, Fluorescence lifetime imaging, Pancreatic cancer, Multiphoton microscopy, Multiphoton fluorescence microscopy, Luminescence, Gold, Microscopy

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Proceedings Article | 21 February 2017 Paper

Paper

Fluorescence lifetime imaging of calcium flux in neurons in response to pulsed infrared light

Alex Walsh, Anna Sedelnikova, Gleb Tolstykh, Bennett Ibey, Hope Beier

Proceedings Volume 10069, 100691B (2017) https://doi.org/10.1117/12.2249522

KEYWORDS: Scanners, Calcium, Infrared radiation, Neurons, Fluorescence lifetime imaging, Multiphoton microscopy, Action potentials, Ions, Photon counting

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Proceedings Article | 15 February 2017 Paper

Paper

Short infrared laser pulses increase cell membrane fluidity

Alex Walsh, Jody Cantu, Bennett Ibey, Hope Beier

Proceedings Volume 10062, 100620D (2017) https://doi.org/10.1117/12.2249521

KEYWORDS: Infrared radiation, Infrared imaging, Infrared lasers, Photothermal effect, Neurons, Temperature metrology, Thermal modeling, Optical filters

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Proceedings Article | 8 February 2017 Paper

Paper

Density-based clustering analyses to identify heterogeneous cellular sub-populations

Tiffany Heaster, Alex Walsh, Bennett Landman, Melissa Skala

Proceedings Volume 10043, 100430X (2017) https://doi.org/10.1117/12.2252499

KEYWORDS: Breast cancer, Resistance, Fluorescence lifetime imaging, Algorithm development, Breast, Spatial analysis, Optical imaging, Cancer, Tumors, Statistical modeling, Biological research, Tumor growth modeling, Statistical analysis, Data modeling, Oncology

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Proceedings Article | 8 February 2017 Paper

Paper

Short infrared laser pulses block action potentials in neurons

Alex Walsh, Gleb Tolstykh, Stacey Martens, Bennett Ibey, Hope Beier

Proceedings Volume 10052, 100520J (2017) https://doi.org/10.1117/12.2249519

KEYWORDS: Action potentials, Neurons, Infrared lasers, Optogenetics, Infrared radiation, Thermal effects, Neurophysiology, Microscopes, Luminescence, Surface plasmons, Cameras, Infrared imaging, Argon ion lasers

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SPIE Journal Paper | 1 December 2016 Open Access

Open Access

Action potential block in neurons by infrared light

Alex Walsh, Gleb Tolstykh, Stacey Martens, Bennett Ibey, Hope Beier

NPh, Vol. 3, Issue 04, 040501, (December 2016) https://doi.org/10.1117/12.10.1117/1.NPh.3.4.040501

KEYWORDS: Neurons, Infrared radiation, Luminescence, Thermography, Action potentials, Optogenetics, 3D modeling, Infrared imaging, Thermal modeling, Surface plasmons

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Proceedings Article | 14 March 2016 Paper

Paper

Temporal and spatial binning of TCSPC data to improve signal-to-noise ratio and imaging speed

Alex Walsh, Hope Beier

Proceedings Volume 9712, 97120R (2016) https://doi.org/10.1117/12.2208880

KEYWORDS: Deconvolution, Fluorescence lifetime imaging, Single photon, Data acquisition, Signal to noise ratio, Microscopes, Pulsed laser operation, Error analysis, Computer simulations, Temporal resolution

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Proceedings Article | 9 March 2016 Paper

Paper

All optical experimental design for neuron excitation, inhibition, and action potential detection

Alex Walsh, Gleb Tolstykh, Stacey Martens, Anna Sedelnikova, Bennett Ibey, Hope Beier

Proceedings Volume 9690, 96901P (2016) https://doi.org/10.1117/12.2208887

KEYWORDS: Luminescence, Cameras, Neurophysiology

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Proceedings Article | 9 March 2016 Presentation + Paper

Presentation + Paper

Differentiating quiescent cancer cell populations in heterogeneous samples with fluorescence lifetime imaging

Tiffany Heaster, Alex Walsh, Melissa Skala

Proceedings Volume 9719, 97190L (2016) https://doi.org/10.1117/12.2211734

KEYWORDS: Cancer, Fluorescence lifetime imaging, Luminescence, Data modeling, Oncology, Two photon excitation microscopy, Leukemia, Resistance, Picosecond phenomena, Cell death, Optical imaging, Image analysis

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SPIE Journal Paper | 29 July 2015 Open Access

Open Access

Blind deconvolution estimation of fluorescence measurements through quadratic programming

Daniel Campos-Delgado, Omar Gutierrez-Navarro, Edgar Arce-Santana, Melissa Skala, Alex Walsh, Javier Jo

JBO, Vol. 20, Issue 07, 075010, (July 2015) https://doi.org/10.1117/12.10.1117/1.JBO.20.7.075010

KEYWORDS: Luminescence, Deconvolution, Fluorescence lifetime imaging, Error analysis, Statistical analysis, Biological research, Computer programming, Statistical modeling, Breast cancer, Instrument modeling

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SPIE Journal Paper | 20 February 2015 Open Access

Open Access

Collagen density and alignment in responsive and resistant trastuzumab-treated breast cancer xenografts

Alex Walsh, Rebecca Cook, Jae Lee, Carlos Arteaga, Melissa Skala

JBO, Vol. 20, Issue 02, 026004, (February 2015) https://doi.org/10.1117/12.10.1117/1.JBO.20.2.026004

KEYWORDS: Tumors, Collagen, Second-harmonic generation, Breast cancer, Optical alignment, Tissues, In vivo imaging, Statistical analysis, Harmonic generation, Receptors

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SPIE Journal Paper | 29 January 2015 Open Access

Open Access

High-throughput measurements of the optical redox ratio using a commercial microplate reader

Taylor Cannon, Amy Shah, Alex Walsh, Melissa Skala

JBO, Vol. 20, Issue 01, 010503, (January 2015) https://doi.org/10.1117/12.10.1117/1.JBO.20.1.010503

KEYWORDS: Luminescence, Breast cancer, Mode conditioning cables, Microscopy, Receptors, Optical testing, Drug development, Multiphoton microscopy, Confocal microscopy, Signal detection

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Proceedings Article | 28 February 2014 Paper

Paper

An automated image processing routine for segmentation of cell cytoplasms in high-resolution autofluorescence images

Alex Walsh, Melissa Skala

Proceedings Volume 8948, 89481M (2014) https://doi.org/10.1117/12.2040644

KEYWORDS: Image segmentation, Image processing, Luminescence, Image compression, Tumors, Cancer, Image analysis, Breast cancer, Image resolution, Mode conditioning cables

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Proceedings Article | 22 February 2013 Paper

Paper

Optical metabolic imaging of live tissue cultures

Alex Walsh, Rebecca Cook, Carlos Arteaga, Melissa Skala

Proceedings Volume 8588, 858820 (2013) https://doi.org/10.1117/12.2001863

KEYWORDS: Luminescence, Tissues, Tissue optics, In vivo imaging, Tumors, Optical imaging, Mode conditioning cables, Photons, Cancer, Image resolution

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SPIE Journal Paper | 1 November 2012 Open Access

Open Access

Ex vivo optical metabolic measurements from cultured tissue reflect in vivo tissue status

Alex Walsh, Kristin Poole, Craig Duvall, Melissa Skala

JBO, Vol. 17, Issue 11, 116015, (November 2012) https://doi.org/10.1117/12.10.1117/1.JBO.17.11.116015

KEYWORDS: In vivo imaging, Tissue optics, Tissues, Luminescence, Biopsy, Optical testing, Biomedical optics, Mode conditioning cables, Cell death, Optical imaging

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Proceedings Article | 23 February 2010 Paper

Paper

Effects of temperature on fluorescence in human tissue

D. Masters, Alex Walsh, A. Welch, Anita Mahadevan-Jansen

Proceedings Volume 7562, 75620V (2010) https://doi.org/10.1117/12.842488

KEYWORDS: Luminescence, Tissues, Optical properties, In vitro testing, In vivo imaging, Temperature metrology, Skin, Monte Carlo methods, Tissue optics, Breast

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Proceedings Article | 12 February 2010 Paper

Paper

The effect of temperature of fluorescence: an animal study

Alex Walsh, Bart Masters, Duco Jansen, A. Welch, Anita Mahadevan-Jansen

Proceedings Volume 7562, 75620W (2010) https://doi.org/10.1117/12.842578

KEYWORDS: Luminescence, Tissues, Temperature metrology, Optical properties, Diffuse reflectance spectroscopy, Skin, Eye, Collagen, Cameras, Tissue optics

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Showing 5 of 39 publications

Proceedings Volume Editor (3)

SPIE Conference Volume | 5 April 2024

Multiscale Imaging and Spectroscopy V

SPIE Conference Volume | 27 March 2024

Optical Interactions with Tissue and Cells XXXV

SPIE Conference Volume | 26 April 2023

Multiscale Imaging and Spectroscopy IV

Conference Committee Involvement (16)

Multiscale Imaging and Spectroscopy VI

25 January 2025 | San Francisco, California, United States

Visualizing and Quantifying Drug Distribution in Tissue IX

25 January 2025 | San Francisco, California, United States

Optical Interactions with Tissue and Cells XXXVI

25 January 2025 | San Francisco, California, United States

Multiscale Imaging and Spectroscopy V

27 January 2024 | San Francisco, California, United States

Optical Interactions with Tissue and Cells XXXV

27 January 2024 | San Francisco, California, United States

Visualizing and Quantifying Drug Distribution in Tissue VIII

27 January 2024 | San Francisco, California, United States

Optical Interactions with Tissue and Cells XXXIV

28 January 2023 | San Francisco, California, United States

Multiscale Imaging and Spectroscopy IV

28 January 2023 | San Francisco, California, United States

Visualizing and Quantifying Drug Distribution in Tissue VII

28 January 2023 | San Francisco, California, United States

Multiscale Imaging and Spectroscopy III

22 January 2022 | San Francisco, California, United States

Visualizing and Quantifying Drug Distribution in Tissue VI

22 January 2022 | San Francisco, California, United States

Multiscale Imaging and Spectroscopy II

6 March 2021 | Online Only, California, United States

Visualizing and Quantifying Drug Distribution in Tissue V

6 March 2021 | Online Only, California, United States

Multiscale Imaging and Spectroscopy

1 February 2020 | San Francisco, California, United States

Visualizing and Quantifying Drug Distribution in Tissue IV

1 February 2020 | San Francisco, California, United States

Visualizing and Quantifying Drug Distribution in Tissue III

2 February 2019 | San Francisco, California, United States

Showing 5 of 16 Conference Committees

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