You searched for +publisher:"University of Texas – Austin" +contributor:("Dunn, Andrew Kenneth, 1970-").
Showing records 1 – 21 of
21 total matches.
No search limiters apply to these results.
University of Texas – Austin
1.
Arkin, Jeremy Sandon.
Investigation into optimizing laser speckle contrast imaging illumination.
Degree: MSin Engineering, Biomedical Engineering, 2017, University of Texas – Austin
URL: http://hdl.handle.net/2152/61564 
► The primary purpose of this work is to optimize the illumination parameters used for laser speckle imaging and investigate how spatial modulation of the light…
(more)
▼ The primary purpose of this work is to optimize the illumination parameters used for laser speckle imaging and investigate how spatial modulation of the light used for illumination can enhance the sampling volume. An in-line illumination scheme is detailed that removes the need to manually position a side mounted coherent light source, instead utilizing a polarizing beam splitter (PBS) and linear polarizer to illuminate the sample plane through the same objective used to collect the backscattered light. This method ensures repeated, robust interrogation of the sample plane and allows for control over the light intensity using the polarizing elements.
Spatial modulation of the illumination beam was then investigated as a method to increase the depth-penetration of LSCI. The premise was to use a focused beam of light, as opposed to a traditional wide-field beam, and illuminate the sample at various distances from the detector increasing the probability scattered photons sample deeper volumes. Single and two-point source configurations were used to image a microfluidic phantom with added static scattering layers to simulate different vessel depths. Varying the distance between the source and the detector, the camera field of view (FOV), we showed that it is possible to collect information from submerged vessels using a non-full field approach. This led to the design and implementation of an in-line, DMD-based illumination scheme that allows the projection and modulation of spatially complex illumination schemes.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor).
Subjects/Keywords: Laser speckle contrast imaging; Illumination
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Arkin, J. S. (2017). Investigation into optimizing laser speckle contrast imaging illumination. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/61564
Chicago Manual of Style (16th Edition):
Arkin, Jeremy Sandon. “Investigation into optimizing laser speckle contrast imaging illumination.” 2017. Masters Thesis, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/61564.
MLA Handbook (7th Edition):
Arkin, Jeremy Sandon. “Investigation into optimizing laser speckle contrast imaging illumination.” 2017. Web. 20 Jan 2021.
Vancouver:
Arkin JS. Investigation into optimizing laser speckle contrast imaging illumination. [Internet] [Masters thesis]. University of Texas – Austin; 2017. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/61564.
Council of Science Editors:
Arkin JS. Investigation into optimizing laser speckle contrast imaging illumination. [Masters Thesis]. University of Texas – Austin; 2017. Available from: http://hdl.handle.net/2152/61564
University of Texas – Austin
2.
Olin, Katherine Elizabeth.
Characterizing the depth dependence of resolution and signal strength for two-photon microscopy.
Degree: MSin Engineering, Biomedical Engineering, 2018, University of Texas – Austin
URL: http://hdl.handle.net/2152/68025
► Two-photon (2P) microscopy is a useful tool for studying structure and function of biological samples. As optical optimizations occur in 2P systems that allow imaging…
(more)
▼ Two-photon (2P) microscopy is a useful tool for studying structure and function of biological samples. As optical optimizations occur in 2P systems that allow imaging at deeper depths, there is a need to characterize the resolution and the signal interactions with tissue at these depths. Here, we discuss processes to determine the resolution of a 2P microscope using sub-resolution sized micro-spheres to mimic point spread functions. Through this process, the resolution of the microscope was determined to be about 0.942 μm in vitro and about 1.08 μm in vivo, values that did not change with respect to depth. Additionally, we investigated the relationship between contrast, background intensity, and noise with depth in vivo. From this study, contrast decreased with depth, while background intensity and noise both increased. These results suggest that the decrease in resolving power at deep depths is likely due to the inability to differentiate signal from background and not due to a decrease in the overall resolution of the system.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor).
Subjects/Keywords: Two-photon microscopy; Resolution; Signal strength; Biological samples
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Olin, K. E. (2018). Characterizing the depth dependence of resolution and signal strength for two-photon microscopy. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/68025
Chicago Manual of Style (16th Edition):
Olin, Katherine Elizabeth. “Characterizing the depth dependence of resolution and signal strength for two-photon microscopy.” 2018. Masters Thesis, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/68025.
MLA Handbook (7th Edition):
Olin, Katherine Elizabeth. “Characterizing the depth dependence of resolution and signal strength for two-photon microscopy.” 2018. Web. 20 Jan 2021.
Vancouver:
Olin KE. Characterizing the depth dependence of resolution and signal strength for two-photon microscopy. [Internet] [Masters thesis]. University of Texas – Austin; 2018. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/68025.
Council of Science Editors:
Olin KE. Characterizing the depth dependence of resolution and signal strength for two-photon microscopy. [Masters Thesis]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/68025
3.
Mark, Andrew Evan.
Computational modeling of stimulated emission depletion microscopy in biological cells under one- and two-photon excitation.
Degree: MSin Engineering, Electrical and Computer Engineering, 2014, University of Texas – Austin
URL: http://hdl.handle.net/2152/28265
► The finite-difference time-domain method is used to simulate the propagation of focused beams used for stimulated emission depletion (STED) microscopy as they scatter through layers…
(more)
▼ The finite-difference time-domain method is used to simulate the propagation of focused beams used for stimulated emission depletion (STED) microscopy as they scatter through layers of biological cells. Depletion beams that facilitate axial and lateral confinement of the fluorescence emission are modeled, and the effective point spread function of the system as a function of focal depth is assessed under one- and two-photon excitation. Results show that the lateral depletion beam retains a well-defined minimum up to the maximum simulation depth of 42 µm. In addition, the relative spatial shift between excitation and de-excitation beam foci is less than 44 nm for all simulated depths. PSF calculations suggest that sub-diffraction imaging is possible beyond the maximum simulated depth, as long as the fluorescence emission is detectable. However, strong attenuation of the fluorescence emission by the axial confinement beam may make this beam unsuitable for sub-diffraction imaging in scattering samples.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor).
Subjects/Keywords: STED microscopy; Scattering; Optical microscopy; Computer simulation
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Mark, A. E. (2014). Computational modeling of stimulated emission depletion microscopy in biological cells under one- and two-photon excitation. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/28265
Chicago Manual of Style (16th Edition):
Mark, Andrew Evan. “Computational modeling of stimulated emission depletion microscopy in biological cells under one- and two-photon excitation.” 2014. Masters Thesis, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/28265.
MLA Handbook (7th Edition):
Mark, Andrew Evan. “Computational modeling of stimulated emission depletion microscopy in biological cells under one- and two-photon excitation.” 2014. Web. 20 Jan 2021.
Vancouver:
Mark AE. Computational modeling of stimulated emission depletion microscopy in biological cells under one- and two-photon excitation. [Internet] [Masters thesis]. University of Texas – Austin; 2014. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/28265.
Council of Science Editors:
Mark AE. Computational modeling of stimulated emission depletion microscopy in biological cells under one- and two-photon excitation. [Masters Thesis]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/28265
4.
Schrandt, Christian John.
Chronic monitoring of cortical hemodynamics after ischemic stroke using funcional optical imaging techniques.
Degree: PhD, Biomedical Engineering, 2015, University of Texas – Austin
URL: http://hdl.handle.net/2152/30334
► The roles of the vascular architecture and blood flow in response to neurovascular diseases are important in predicting physiological outcomes. Observing these parameters chronically with…
(more)
▼ The roles of the vascular architecture and blood flow in response to neurovascular diseases are important in predicting physiological outcomes. Observing these parameters chronically with optical imaging techniques provides insight into the neurovascular recovery process. We develop and deploy optical imaging systems for monitoring the progression of vascular structure, perfusion, and functional blood response after ischemic stroke in a chronic rodent model to observe vascular dynamics of the cortex under normal and diseased pathologies.
Specifically, we monitor the progression of the vascular structure and cerebral blood flow (CBF) over a chronic period in the rodent cortex after photo-thrombotic occlusion. Multi-Exposure Speckle Imaging (MESI) provides surface measurements of microvascular flow dynamics while Two-Photon Fluorescence Microscopy offers direct visualization of the microvascular structure. We observe the occurrence of vascular reorientation in the sub-surface microvascular structure over a 35 day post-occlusion period. We also correlate MESI flow estimates in the parenchyma with sub-surface microvascular volume fractions from two-photon microscopy to assess how vascular density influences the surface-integrated MESI measurements.
Next, we develop and validate a MESI technique for measuring absolute changes of the functional blood flow response to forepaw stimulation in rodents, termed FA MESI. The optimal camera exposures for capturing the CBF response to forepaw stimulation are extracted from a training set of animal data and the feasibility of the technique is demonstrated in a testing animal set by comparing functional response results between new and existing techniques. We then deploy this system in a chronic study monitoring the progression of hemodynamic parameters after ischemic stroke within the functionally responding area of the cortex. The progression of the regional CBF perfusion and absolute changes in the magnitude of the functional blood flow response are monitored chronically after photo-thrombotic occlusion. We compare the differences between absolute and relative measurements of the functional blood flow responses, and validate FA MESI by comparing baseline measurements to 15-exposure MESI over the sampled flow distributions. We demonstrate the differences measured between the functional outcomes and the regional CBF perfusion over a three week post-occlusion time period.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor).
Subjects/Keywords: Chronic stroke imaging; Ischemic stroke; Multi-exposure speckle imaging; Two-photon microscopy; Vascular remodeling; Cortical hemodynamics; Functional activation
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Schrandt, C. J. (2015). Chronic monitoring of cortical hemodynamics after ischemic stroke using funcional optical imaging techniques. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/30334
Chicago Manual of Style (16th Edition):
Schrandt, Christian John. “Chronic monitoring of cortical hemodynamics after ischemic stroke using funcional optical imaging techniques.” 2015. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/30334.
MLA Handbook (7th Edition):
Schrandt, Christian John. “Chronic monitoring of cortical hemodynamics after ischemic stroke using funcional optical imaging techniques.” 2015. Web. 20 Jan 2021.
Vancouver:
Schrandt CJ. Chronic monitoring of cortical hemodynamics after ischemic stroke using funcional optical imaging techniques. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2015. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/30334.
Council of Science Editors:
Schrandt CJ. Chronic monitoring of cortical hemodynamics after ischemic stroke using funcional optical imaging techniques. [Doctoral Dissertation]. University of Texas – Austin; 2015. Available from: http://hdl.handle.net/2152/30334
5.
Weber, Erica L.
Quantifying the impact of thermal lensing on visual function in ocular media.
Degree: PhD, Biomedical Engineering, 2012, University of Texas – Austin
URL: http://hdl.handle.net/2152/22130
► Several studies have been conducted in the past which determined that some near-infrared (NIR) sources are capable of inducing a thermal lens within ocular media…
(more)
▼ Several studies have been conducted in the past which determined that some near-infrared (NIR) sources are capable of inducing a thermal lens within ocular media of rhesus and, potentially, human subjects. Typically, the role of thermal lensing in the eye was explored in terms of its influence on damage thresholds for these NIR lasers entering the eye. However, the effect of a thermal lens on visible wavefronts entering the eye has yet to be explored. In recent years military and law enforcement agencies in the United States and elsewhere have devoted considerable resources to the area of "non-lethal weapons." Devices such as tasers, spike strips and ocular interruption (OI) devices provide the user with an escalation of force while minimizing casualties and collateral damage. One particular form of OI device, the laser dazzler, employs a visible laser capable of saturating retinal receptors causing a temporary flash blindness effect. While these visible devices have proven safe and effective in the field, an inherent risk exists when any light source is used to saturate retinal tissue. By adding the use of a thermal lens, these OI devices would create significant distortions in the visible wavefront to alter vision and/or increase the diameter of a focused visible dazzler at the retina to both improve safety and effectiveness of the visible device. This dissertation describes experiments involving artificial eye, human subject, and computational modeling which were conducted to quantify the impact of thermal lensing on visual acuity.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor).
Subjects/Keywords: Thermal lensing; Visual acuity
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Weber, E. L. (2012). Quantifying the impact of thermal lensing on visual function in ocular media. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/22130
Chicago Manual of Style (16th Edition):
Weber, Erica L. “Quantifying the impact of thermal lensing on visual function in ocular media.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/22130.
MLA Handbook (7th Edition):
Weber, Erica L. “Quantifying the impact of thermal lensing on visual function in ocular media.” 2012. Web. 20 Jan 2021.
Vancouver:
Weber EL. Quantifying the impact of thermal lensing on visual function in ocular media. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/22130.
Council of Science Editors:
Weber EL. Quantifying the impact of thermal lensing on visual function in ocular media. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/22130
University of Texas – Austin
6.
Miller, David Roger.
Extending the depth limit of multiphoton microscopy for in vivo brain imaging.
Degree: MSin Engineering, Biomedical engineering, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/41746
► The benefit of high-resolution imaging provided by optical microscopy has resulted in many discoveries in both biology and neuroscience. Two-photon fluorescence microscopy (2PM) is widely…
(more)
▼ The benefit of high-resolution imaging provided by optical microscopy has resulted in many discoveries in both biology and neuroscience. Two-photon fluorescence microscopy (2PM) is widely used for in vivo brain imaging to visualize cerebral vasculature and neuronal physiology. Conventional 2PM using titanium-doped sapphire oscillators is typically limited to imaging depths less than 600 um due to their short excitation wavelengths (700 -1,000 nm) and low pulse energy (~10 nJ). The ideal approach for deep imaging is to use both longer wavelengths to reduce the effects of scattering by heterogeneous brain tissue and higher energy pulses such that more photons reach the excitation volume at deeper tissue depths. I perform high-resolution, non-invasive, in vivo deep-tissue imaging of the mouse neocortex using multiphoton microscopy with a high repetition rate optical parametric amplifier (OPA). The OPA outputs 400 nJ pulse energies and is tunable from 1,100 to 1,400 nm. The tunability of the OPA is an advantage over other high-pulse-energy lasers because the OPA wavelength can be matched to the peak absorption of the target fluorophore, enabling the excitation of numerous different fluorophores. I demonstrate an imaging depth of 1,200 um in vasculature labeled with
Texas Red and 1,
160 um in neurons labeled with tdTomato, and perform line scans as deep as 1200 um to measure the blood flow speed in a single capillary. I also demonstrate deep-tissue imaging using Indocyanine Green (ICG), which is FDA approved and a promising route to translate multiphoton microscopy to human applications.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Yeh, Hsin-Chih "Tim" (committee member).
Subjects/Keywords: Multiphoton microscopy; Optical parametric amplifier; Deep-tissue brain imaging
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Miller, D. R. (2016). Extending the depth limit of multiphoton microscopy for in vivo brain imaging. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/41746
Chicago Manual of Style (16th Edition):
Miller, David Roger. “Extending the depth limit of multiphoton microscopy for in vivo brain imaging.” 2016. Masters Thesis, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/41746.
MLA Handbook (7th Edition):
Miller, David Roger. “Extending the depth limit of multiphoton microscopy for in vivo brain imaging.” 2016. Web. 20 Jan 2021.
Vancouver:
Miller DR. Extending the depth limit of multiphoton microscopy for in vivo brain imaging. [Internet] [Masters thesis]. University of Texas – Austin; 2016. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/41746.
Council of Science Editors:
Miller DR. Extending the depth limit of multiphoton microscopy for in vivo brain imaging. [Masters Thesis]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/41746
7.
Davis, Mitchell Alan.
Monte Carlo simulation of fluorescence imaging of microvasculature.
Degree: MSin Engineering, Electrical and Computer Engineering, 2011, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2011-08-4191
► Little numerical analysis has been done on fluorescence lifetime imaging \emph{in-vivo}. Here, a 3D fluorescence Monte Carlo model is used to evaluate a microvasculature geometry…
(more)
▼ Little numerical analysis has been done on fluorescence lifetime imaging \emph{in-vivo}. Here, a 3D fluorescence Monte Carlo model is used to evaluate a microvasculature geometry obtained via two-photon microscopy. I found that a bulk-vascularization assumption does not provide an accurate picture of penetration depth of the collected fluorescence signal. Instead the degree of absorption difference between extravascular and intravascular space, as well as the absorption difference between excitation and emission wavelengths must be taken into account to determine the depth distribution. Additionally, I found that using targeted illumination can provide for superior surface vessel sensitivity over wide-field illumination, with small area detection offering an even greater amount of sensitivity to surface vasculature. Depth sensitivity can be enhanced by either increasing the detector area or increasing the illumination area. Finally, it is shown that the excitation wavelength and vessel size can affect intra-vessel sampling distribution, as well as the amount of signal that originates from inside the vessel under targeted illumination conditions.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Pearce, John A., 1946- (advisor).
Subjects/Keywords: Light propagation in tissues
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Davis, M. A. (2011). Monte Carlo simulation of fluorescence imaging of microvasculature. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-08-4191
Chicago Manual of Style (16th Edition):
Davis, Mitchell Alan. “Monte Carlo simulation of fluorescence imaging of microvasculature.” 2011. Masters Thesis, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/ETD-UT-2011-08-4191.
MLA Handbook (7th Edition):
Davis, Mitchell Alan. “Monte Carlo simulation of fluorescence imaging of microvasculature.” 2011. Web. 20 Jan 2021.
Vancouver:
Davis MA. Monte Carlo simulation of fluorescence imaging of microvasculature. [Internet] [Masters thesis]. University of Texas – Austin; 2011. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-4191.
Council of Science Editors:
Davis MA. Monte Carlo simulation of fluorescence imaging of microvasculature. [Masters Thesis]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-08-4191
8.
Bhave, Gauri Suresh.
Micro-patterning colloidal quantum dots based light sources for cellular array imaging.
Degree: PhD, Biomedical Engineering, 2014, University of Texas – Austin
URL: http://hdl.handle.net/2152/26872
► Lab-on-chip systems have been developed for various applications like point of care diagnostics and compact imaging systems. Compact, on-chip imaging systems face a challenge in…
(more)
▼ Lab-on-chip systems have been developed for various applications like point of care diagnostics and compact imaging systems. Compact, on-chip imaging systems face a challenge in the integration of multicolor light sources on-chip. This is because of the unavailability of compact, individually addressable, multicolor light sources on a single planar substrate. Colloidal Quantum Dot based Light Emitting Diodes (QDLEDs), which have found wide appeal, due to their unique properties like their tunable and narrow emission bandwidth and easy fabrication, are ideal for lab-on-chip integration. Among different types of QDLED structures implemented, inorganic QDLEDs have shown great promise. We have demonstrated designs and fabrication strategies for creating QDLEDs with enhanced performance. In particular: (I) We introduce a sandwich structure with a spin coated inorganic hole transporting layer of nickel oxide underlying the QD layer and with a spin coated zinc oxide electron transporting layer, with patterning of anode and cathode on the substrate. Compared to the use of sputtered thin films, solution processed charge transporting layers (CTLs) improve robustness of the device, as crystalline ZnO shows low CB and VB edge energy levels, efficiently suppressing hole leakage current resulting in LEDs with longer lifetimes. We also use Atomic Layer Deposition to deposit an additional hole injecting layer to protect the QDs from direct contact with the anode. With this device design, we demonstrate a working lifetime of more than 12 hours and a shelf-life of more than 240 days for the devices. Our solution based process is applicable to micro-contact printed and also spin-coated QD films. QDLEDs with spin-coated CTLs show a lifetime increase of more than three orders of magnitude compared to devices made using sputtered CTLs. (II) We implement strategies of the enhancement of light extraction from the fabricated QDLEDs. We discuss the integration of a two dimensional grating structure based on a metal-dielectric-metal plasmonic waveguide with the metal electrode of a QDLED, with the aim of enhancing the light intensity by resonant suppression of transmitted light. The grating structure reflects the light coupled with the metal electrode in the QDLED and we found an increase of 34.72% in the electroluminescence intensity from the area of the pattern and an increase of 32.63% from photoluminescence of QDs deposited on a metal surface. (III) We demonstrate the capability of our fabricated devices as a light source by measuring intensity across stained cells with QDLEDs of two different wavelengths and show the correlation as expected with the absorption profile of the fluorescent dye. We measure the absorption from the biological samples using QDLEDs fabricated with various design modifications, as a quantification of the improvements in device performance, directly affecting to our target application.
Advisors/Committee Members: Zhang, John X. J. (advisor), Dunn, Andrew Kenneth, 1970- (advisor).
Subjects/Keywords: Quantum dot; LEDs; Plasmonic; Cell imaging
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Bhave, G. S. (2014). Micro-patterning colloidal quantum dots based light sources for cellular array imaging. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/26872
Chicago Manual of Style (16th Edition):
Bhave, Gauri Suresh. “Micro-patterning colloidal quantum dots based light sources for cellular array imaging.” 2014. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/26872.
MLA Handbook (7th Edition):
Bhave, Gauri Suresh. “Micro-patterning colloidal quantum dots based light sources for cellular array imaging.” 2014. Web. 20 Jan 2021.
Vancouver:
Bhave GS. Micro-patterning colloidal quantum dots based light sources for cellular array imaging. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/26872.
Council of Science Editors:
Bhave GS. Micro-patterning colloidal quantum dots based light sources for cellular array imaging. [Doctoral Dissertation]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/26872
University of Texas – Austin
9.
-9009-1481.
Improving optical access, sampling speed, and resolution for in vivo multiphoton microscopy.
Degree: PhD, Biomedical Engineering, 2020, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/8974
► Multiphoton microscopy is a powerful optical imaging modality renowned for its non-invasive nature and relatively affordable characteristics. In particular, it has found its niche in…
(more)
▼ Multiphoton microscopy is a powerful optical imaging modality renowned for its non-invasive nature and relatively affordable characteristics. In particular, it has found its niche in neuroimaging due to its ability to probe in vivo biological processes in scattering brain tissue approaching millimeter depths with cellular resolution. However, the brain is a large and complex organ, and in order to fully understand its heterogeneous architecture and associated functional roles, several distal regions must be imaged simultaneously. Moreover, due to the critical implications of organelle features in various macroscale processes, whole-brain imaging at subcellular resolution scales presents itself as one of the outstanding challenges faced by the neuroscientific community today. Primarily, this research aims to expand the depth, field-of-view, and temporal throughput of multiphoton microscopy to enable large volume imaging of microvasculature at greater acquisition speeds. To accomplish this, we combine multi-faceted efforts focused on the engineering and development of advanced multiphoton microscopy techniques and technologies. This includes the characterization of novel contrast agents, the optimization of scan system optics, and the integration of high-repetition rate lasers with a resonant galvanometer. In addition, we develop a two-color imaging system capable of enhancing excitation efficiency, improving signal-to- background ratio, and further extending imaging depth. Finally, we present a novel application for two-color non-degenerate mode mixing to effectively circumvent the diffraction-limited nature of optical resolution and enable subcellular imaging. Collectively, these efforts advance the state-of-the art of multiphoton microscopy for routine cerebrovascular and neuroimaging.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Harris, Kristen (committee member), Milner, Thomas (committee member), Yeh, Hsin-Chih (Tim) (committee member).
Subjects/Keywords: Multiphoton microscopy; Ultrafast lasers; Super-resolution optics
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
-9009-1481. (2020). Improving optical access, sampling speed, and resolution for in vivo multiphoton microscopy. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/8974
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-9009-1481. “Improving optical access, sampling speed, and resolution for in vivo multiphoton microscopy.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://dx.doi.org/10.26153/tsw/8974.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-9009-1481. “Improving optical access, sampling speed, and resolution for in vivo multiphoton microscopy.” 2020. Web. 20 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-9009-1481. Improving optical access, sampling speed, and resolution for in vivo multiphoton microscopy. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Jan 20].
Available from: http://dx.doi.org/10.26153/tsw/8974.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-9009-1481. Improving optical access, sampling speed, and resolution for in vivo multiphoton microscopy. [Doctoral Dissertation]. University of Texas – Austin; 2020. Available from: http://dx.doi.org/10.26153/tsw/8974
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
10.
Estrada, Arnold Delfino.
High-resolution measurement of dissolved oxygen concentration in vivo using two-photon microscopy.
Degree: PhD, Biomedical Engineering, 2011, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2011-05-2806
► Because oxygen is vital to the metabolic processes of all eukaryotic cells, a detailed understanding of its transport and consumption is of great interest to…
(more)
▼ Because oxygen is vital to the metabolic processes of all eukaryotic cells, a detailed understanding of its transport and consumption is of great interest to researchers. Existing methods of quantifying oxygen delivery and consumption are non-ideal for in vivo measurements. They either lack the three-dimensional spatial resolution needed, are invasive and disturb the local physiology, or they rely on hemoglobin spectroscopy, which is not a direct measure of the oxygen available to cells. Consequently, many fundamental physiology research questions remain unanswered. This dissertation presents our development of a novel in vivo oxygen measurement technique that seeks to address the shortcomings of existing methods. Specifically, we have combined two-photon microscopy with phosphorescence quenching oximetry to produce a system that is capable of performing depth-resolved, high-resolution dissolved oxygen concentration (PO2) measurements. Furthermore, the new technique allows for simultaneous visualization of the micro-vasculature and measurement of blood velocity. We demonstrate the technique by quantifying PO2 in rodent cortical vasculature under normal and pathophysiologic conditions. We also demonstrate the technique’s usefulness in examining the changes in oxygen transport that result from acute focal ischemia in rodent animal models.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Tunnell, James (committee member), Milner, Thomas (committee member), Rylander, Grady (committee member), Ress, David (committee member).
Subjects/Keywords: Two-photon; Multiphoton; Phosphorescence quenching; Oxygen sensing; PO2; Partial pressure of oxygen; Microscopy; In vivo; Oxygen transport
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Estrada, A. D. (2011). High-resolution measurement of dissolved oxygen concentration in vivo using two-photon microscopy. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-05-2806
Chicago Manual of Style (16th Edition):
Estrada, Arnold Delfino. “High-resolution measurement of dissolved oxygen concentration in vivo using two-photon microscopy.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/ETD-UT-2011-05-2806.
MLA Handbook (7th Edition):
Estrada, Arnold Delfino. “High-resolution measurement of dissolved oxygen concentration in vivo using two-photon microscopy.” 2011. Web. 20 Jan 2021.
Vancouver:
Estrada AD. High-resolution measurement of dissolved oxygen concentration in vivo using two-photon microscopy. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-2806.
Council of Science Editors:
Estrada AD. High-resolution measurement of dissolved oxygen concentration in vivo using two-photon microscopy. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-2806
University of Texas – Austin
11.
Davis, Mitchell Alan.
Three dimensional simulation of functional neuro-vascular imaging.
Degree: PhD, Electrical and Computer Engineering, 2014, University of Texas – Austin
URL: http://hdl.handle.net/2152/38225
► Functional optical imaging has become a powerful tool for measuring physiological parameters in the brain without disrupting normal physiology. Fluorescence lifetime imaging (FLIM) has been…
(more)
▼ Functional optical imaging has become a powerful tool for measuring physiological parameters in the brain without disrupting normal physiology. Fluorescence lifetime imaging (FLIM) has been shown to allow near real time mapping of oxygen tension in plasma (pO2), and Laser Speckle Contrast Imaging (LSCI) has been demonstrated to provide qualitative assessments of blood flow in the cortex. However, as both of these methods provide physiological parameters based on the spatial sampling of photons arriving at a detector, it is crucially important to understand either where the photons originated, in the case of FLIM, or which moving particles the photons have sampled, in the case of LSCI. Traditionally, these questions have been difficult to solve because of the heterogeneity of the distribution of particles which contribute to the measured signal. In both FLIM and LSCI, for example, only the light which samples the intravascular space will contribute to the signal. While analytical methods have proven to be successful at predicting the imaging depth of homogeneous materials, they are not able to predict imaging depth when measuring a fluorophore or a moving particle that is only present inside blood vessels. Unlike analytical methods, numerical methods can be used to approximate light propagation in an arbitrary geometry. While both deterministic and stochastic models of light propagation can, and have been, successfully employed to determine light fluence in an arbitrary geometry, deterministic methods are not well suited to the task of simulating light propagation in large volumes of turbid media. For this reason, three dimensional Monte Carlo simulations of light propagation combined with high resolution vascular anatomy were used to directly simulate FLIM and LSCI in the brain. Using these simulations, the imaging depth, degree of multiple scattering, and sensitivity of LSCI and FLIM to physiological changes were determined.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Pearce, John (committee member), Thomas, Robert (committee member), Tunnell, James (committee member), Ling, Hao (committee member).
Subjects/Keywords: Laser-tissue interactions; Vascular fluorescence imaging; Speckle contrast imaging; Dynamic light scattering; Blood flow imaging
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Davis, M. A. (2014). Three dimensional simulation of functional neuro-vascular imaging. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/38225
Chicago Manual of Style (16th Edition):
Davis, Mitchell Alan. “Three dimensional simulation of functional neuro-vascular imaging.” 2014. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/38225.
MLA Handbook (7th Edition):
Davis, Mitchell Alan. “Three dimensional simulation of functional neuro-vascular imaging.” 2014. Web. 20 Jan 2021.
Vancouver:
Davis MA. Three dimensional simulation of functional neuro-vascular imaging. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/38225.
Council of Science Editors:
Davis MA. Three dimensional simulation of functional neuro-vascular imaging. [Doctoral Dissertation]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/38225
University of Texas – Austin
12.
-6210-7941.
In vivo optical imaging to investigate neurovascular structure and cerebral hemodynamics.
Degree: PhD, Biomedical Engineering, 2018, University of Texas – Austin
URL: http://hdl.handle.net/2152/68100
► The ability to visualize structural features of the brain and associated functional information has fueled a revolution in our understanding of the brain. The optical…
(more)
▼ The ability to visualize structural features of the brain and associated functional information has fueled a revolution in our understanding of the brain. The optical technique two-photon microscopy (2PM) is widely used to study individual neural circuits and blood vessel networks in vivo because it is minimally invasive and provides three-dimensional images with cellular resolution. There is rising interest from neuroscientists for the ability to extend the traditional imaging depth of 2PM, which is typically limited to ∼500 μm below the surface of the brain.
In this dissertation, I detail the development of a novel laser source that enables deep-tissue in vivo multiphoton microscopy imaging of blood vessel networks and neurons. Using an excitation wavelength near 1,300 nm at which scattering in tissue is minimized, I demonstrate the ability to chronically study vascular morphology and dynamics as well as neuron morphology at imaging depths of 1 mm and beyond.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Milner, Thomas E (committee member), Yeh, Hsin-Chih "Tim" (committee member), Jones, Theresa A (committee member).
Subjects/Keywords: Two-photon microscopy; Three-photon microscopy; Deep-tissue brain imaging; Optical parametric amplifier
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
-6210-7941. (2018). In vivo optical imaging to investigate neurovascular structure and cerebral hemodynamics. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/68100
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-6210-7941. “In vivo optical imaging to investigate neurovascular structure and cerebral hemodynamics.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/68100.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-6210-7941. “In vivo optical imaging to investigate neurovascular structure and cerebral hemodynamics.” 2018. Web. 20 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-6210-7941. In vivo optical imaging to investigate neurovascular structure and cerebral hemodynamics. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/68100.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-6210-7941. In vivo optical imaging to investigate neurovascular structure and cerebral hemodynamics. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/68100
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
13.
-4887-3850.
Insights into ischemia-induced dendritic and vascular plasticity through In vivo imaging.
Degree: PhD, Neuroscience, 2018, University of Texas – Austin
URL: http://hdl.handle.net/2152/70610
► Stroke remains a leading cause of long-term disability in adults, and impairments in the upper extremities are particularly common. Many post-stroke remodeling events are activity…
(more)
▼ Stroke remains a leading cause of long-term disability in adults, and impairments in the upper extremities are particularly common. Many post-stroke remodeling events are activity dependent and can be influenced by post-ischemic behavioral experience through similar mechanisms as experience-dependent plasticity. The overarching goal of these dissertation studies was to understand how behavioral experience, in the form of rehabilitative training (RT), after ischemia impacts neuronal and vascular structural remodeling.
This was tested using a mouse model of ischemia-induced upper-limb impairments in adult transgenic mice containing yellow or green fluorescent protein (YFP/GFP) in a subset of layer V cortical pyramidal neurons. First, I examined the impact of manual skill learning on dendritic spine dynamics in vivo in the trained motor cortex (MC) of intact mice (Chapter 2). We found that spine formation was significantly enhanced after 3 days of training, which was followed by an equal and opposite increase in spine elimination by day 6 and then a return to baseline levels for the remainder of the training duration. New spines formed on day 3 were preferentially stabilized and were correlated with performance gains.
Next, I tested whether a variation of the photothrombotic stroke model that confines laser illumination to individual arteries on the cortical surface, could better reproduce aspects of the vascular penumbra, such that it would be better suited for examining how structural remodeling events are influenced by the penumbra. We monitored post-ischemic cerebral blood flow (CBF) at 6, 48, and 120 h following MC infarcts and found that artery-targeted photothrombosis created a wider, more graded penumbra. In addition, it instigated vascular structural remodeling, and caused impairments in skilled-reaching performance in mice.
Lastly, I examined the impact of RT on spine dynamics and recovery of skilled reaching performance following photothrombotic infarcts to MC. We found that ischemia instigated widespread increases in spine turnover that persisted for up to 5 weeks. RT increased the stabilization of new spines formed in weeks 2 and 3 after ischemia, which was correlated with improvements in skilled reaching, indicating that new spine maintenance could represent a structural mechanism for the recovery of reaching performance.
Advisors/Committee Members: Jones, Theresa A. (advisor), Dunn, Andrew Kenneth, 1970- (advisor), Harris, Kristen M (committee member), Nishiyama, Hiroshi (committee member), Zemelman, Boris (committee member).
Subjects/Keywords: Ischemia; In vivo imaging; Structural plasticity; Rodent models of focal ischemia
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
-4887-3850. (2018). Insights into ischemia-induced dendritic and vascular plasticity through In vivo imaging. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/70610
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-4887-3850. “Insights into ischemia-induced dendritic and vascular plasticity through In vivo imaging.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/70610.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-4887-3850. “Insights into ischemia-induced dendritic and vascular plasticity through In vivo imaging.” 2018. Web. 20 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-4887-3850. Insights into ischemia-induced dendritic and vascular plasticity through In vivo imaging. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/70610.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-4887-3850. Insights into ischemia-induced dendritic and vascular plasticity through In vivo imaging. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/70610
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
14.
Perillo, Evan Paul.
Nonlinear microscopy methods for imaging and particle tracking in thick biological specimen.
Degree: PhD, Biomedical Engineering, 2017, University of Texas – Austin
URL: http://hdl.handle.net/2152/47440
► Optical microscopy techniques such as single-particle tracking and high-resolution (<500 nm) imaging are critical tools for the advancement of biological research. However most high-resolution optical…
(more)
▼ Optical microscopy techniques such as single-particle tracking and high-resolution (<500 nm) imaging are critical tools for the advancement of biological research. However most high-resolution optical techniques utilize a camera-based or confocal-based detection scheme, which limits the working distance into samples to approximately 10 μm due to light scattering. Nonlinear excitation methods, such as two- and three-photon microscopy, have enabled imaging in thick and scattering samples due to their longer excitation wavelengths and absence of spatial filtering. However, nonlinear excitation is rarely utilized for single-particle tracking as it traditionally offers slightly worse resolution than the aforementioned methods. This dissertation presents the progress made towards adapting nonlinear excitation for high-resolution biological study at scales ranging from single-molecules up to entire tissues. We describe a novel single-particle tracking microscope based upon multiplexed nonlinear illumination, coined TSUNAMI. Single-particle tracking with nanometric resolution using TSUNAMI is demonstrated in live cells and spheroid tumor models to unprecedented depths of 200 μm. Several new long wavelength excitation laser sources are detailed which provide superior image penetration depth compared with traditional sources. Furthermore, we detail a newly discovered form of nonlinear excitation, based upon a two-color, three-photon absorption process, and discuss potential benefits of this new excitation regime. The systems and methods developed in this work will provide life scientists with a powerful toolset for the future of biological research.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Yeh, Tim H. C. (advisor), Milner, Thomas E (committee member), Zheng, Yuebing (committee member).
Subjects/Keywords: Microscopy; Single-particle tracking; Ultrafast lasers; Thick biological specimen; Nonlinear microscopy; Nonlinear excitation; High-resolution biological study; Multiplexed nonlinear illumination; Nanometric resolution
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Perillo, E. P. (2017). Nonlinear microscopy methods for imaging and particle tracking in thick biological specimen. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/47440
Chicago Manual of Style (16th Edition):
Perillo, Evan Paul. “Nonlinear microscopy methods for imaging and particle tracking in thick biological specimen.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/47440.
MLA Handbook (7th Edition):
Perillo, Evan Paul. “Nonlinear microscopy methods for imaging and particle tracking in thick biological specimen.” 2017. Web. 20 Jan 2021.
Vancouver:
Perillo EP. Nonlinear microscopy methods for imaging and particle tracking in thick biological specimen. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/47440.
Council of Science Editors:
Perillo EP. Nonlinear microscopy methods for imaging and particle tracking in thick biological specimen. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://hdl.handle.net/2152/47440
University of Texas – Austin
15.
Kazmi, Syed Mohammad Shams.
Quantitative optical imaging of hemodynamics as platforms for studying neuro-vascular physiology and disease.
Degree: PhD, Biomedical Engineering, 2014, University of Texas – Austin
URL: http://hdl.handle.net/2152/31284
► Blood flow and its payload of molecular oxygen are two parameters of most physiological interest. Systemic tissue health is routinely gauged through measurements of vitals…
(more)
▼ Blood flow and its payload of molecular oxygen are two parameters of most physiological interest. Systemic tissue health is routinely gauged through measurements of vitals and oxygen saturation to estimate the state of these physiological parameters. We design, develop, and deploy optical imaging systems for examining perfusion and oxygenation at the local tissue level and apply these techniques for elucidating the normal and pathological processes associated with neurovascular disease. Specifically, we develop and validate the ability to use Multi-Exposure Speckle Imaging (MESI) to estimate microvascular flow dynamics in rodents over acute and chronic periods. Next, we pose significant optimizations to improve the efficacy of the widefield imaging technique for adoption by bench-side and clinical perfusion studies. We also introduce re-interpretations of the underlying physics to advance the theory that quantifies motion from the imaged speckle patterns. Finally, the technique is deployed for chronic monitoring of cortical flow dynamics before after focal ischemia of the motor cortex as part of a behavioral study in rodents. At the microscale, we develop and validate Two Photon Phosphorescence Lifetime Microscopy (2PLM) to examine dissolved oxygen concentration in microvasculature in three dimensions. We examine the technique’s ability for functional mapping of the rodent cortical microvascular network by quantifying the partial pressure of oxygen (pO₂) before and after occlusion of critical arterioles. Automation of acquisitions and processing for robust oxygen mapping within the micro-vascular network are developed and evaluated. The in vivo results are presented in light of those from studies utilizing more invasive mapping electrodes to provide independent corroboration of the observed neurovascular oxygen distributions. The technique is deployed for examining high resolution functional and structural remodeling after focal cerebral ischemia.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Milner, Thomas E (committee member), Tunnell, James W (committee member), Rylander, H. Grady (committee member), Jones, Theresa A (committee member).
Subjects/Keywords: Optical imaging; Blood flow mapping; Oxygen tension
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Kazmi, S. M. S. (2014). Quantitative optical imaging of hemodynamics as platforms for studying neuro-vascular physiology and disease. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/31284
Chicago Manual of Style (16th Edition):
Kazmi, Syed Mohammad Shams. “Quantitative optical imaging of hemodynamics as platforms for studying neuro-vascular physiology and disease.” 2014. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/31284.
MLA Handbook (7th Edition):
Kazmi, Syed Mohammad Shams. “Quantitative optical imaging of hemodynamics as platforms for studying neuro-vascular physiology and disease.” 2014. Web. 20 Jan 2021.
Vancouver:
Kazmi SMS. Quantitative optical imaging of hemodynamics as platforms for studying neuro-vascular physiology and disease. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/31284.
Council of Science Editors:
Kazmi SMS. Quantitative optical imaging of hemodynamics as platforms for studying neuro-vascular physiology and disease. [Doctoral Dissertation]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/31284
University of Texas – Austin
16.
-0656-3800.
Laser speckle contrast imaging for intraoperative monitoring of cerebral blood flow.
Degree: PhD, Biomedical Engineering, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/63850
► Ensuring adequate blood flow during surgical procedures is crucial, as prolonged ischemia can result in tissue death and lead to poor clinical outcomes. This is…
(more)
▼ Ensuring adequate blood flow during surgical procedures is crucial, as prolonged ischemia can result in tissue death and lead to poor clinical outcomes. This is especially important during neurosurgery, since the brain relies on a constant supply of cerebral blood flow (CBF) to maintain normal function. Intraoperative blood flow monitoring tools are essential to detect ischemia in a timely manner, and allow surgical correction before the onset of irreversible brain injury. Laser speckle contrast imaging (LSCI) is an optical imaging method that provides blood flow maps with high spatiotemporal resolution, and overcomes many of the limitations of current intraoperative monitoring technologies. The objective of this dissertation is to demonstrate that LSCI is an effective tool for blood flow monitoring during neurosurgery, and to optimize and improve LSCI technology for clinical use.
This research has two primary elements: assessing the LSCI instrumentation components in a controlled laboratory setting, and evaluating the clinical performance of LSCI during neurosurgery. The laboratory study aims to determine the optimal specifications for the clinical instrument design, using controlled static and microfluidic flow experiments. Two of the main components of the LSCI instrument are the camera used for recording, and the laser used for coherent illumination of the tissue. Thus, a broad camera and laser comparison was performed spanning a wide array of available hardware options to determine which specifications are the most important for reliable and highly sensitive flow measurements. The two-phase clinical study aims to demonstrate the performance and utility of LSCI in a neurosurgical setting as a potential tool for real-time, continuous, and noninvasive image guidance. These studies demonstrate that LSCI can produce blood flow maps consistent with expected physiological trends, and show the impact of instrument design and image acquisition techniques on image quality and quantitative flow assessment. The results from both the laboratory and clinical studies can be used to design a more sensitive and robust LSCI system, which increases its value as an intraoperative tool for monitoring blood flow. LSCI has the potential to be the next generation of neurosurgical image guidance for blood flow visualization, and the work presented in this dissertation can accelerate its clinical adoption.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Fox, Jr., Douglas J (committee member), Rylander, III, Henry G (committee member), Tunnell, James W (committee member), Emelianov, Stanislav Y (committee member).
Subjects/Keywords: Laser speckle contrast imaging; Cerebral blood flow; Intraoperative imaging
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
-0656-3800. (2016). Laser speckle contrast imaging for intraoperative monitoring of cerebral blood flow. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/63850
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-0656-3800. “Laser speckle contrast imaging for intraoperative monitoring of cerebral blood flow.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/63850.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-0656-3800. “Laser speckle contrast imaging for intraoperative monitoring of cerebral blood flow.” 2016. Web. 20 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-0656-3800. Laser speckle contrast imaging for intraoperative monitoring of cerebral blood flow. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/63850.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-0656-3800. Laser speckle contrast imaging for intraoperative monitoring of cerebral blood flow. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/63850
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
17.
-7772-6051.
Applications of ultrasound and photoacoustics in the central nervous system.
Degree: PhD, Biomedical Engineering, 2017, University of Texas – Austin
URL: http://hdl.handle.net/2152/60433
► Ultrasound imaging has seen a new resurgence in both clinical and preclinical research as demand for affordable and accessible imaging techniques has increased. There are…
(more)
▼ Ultrasound imaging has seen a new resurgence in both clinical and preclinical research as demand for affordable and accessible imaging techniques has increased. There are both therapeutic and imaging applications of ultrasound. In these studies, the feasibility of several new applications for ultrasound-based imaging techniques are explored. Specifically, a new method for measuring the flow of cerebrospinal fluid (CSF) in cerebral shunt systems of patients with hydrocephalus was investigated. A cross-correlation based speckle-tracking algorithm was used to measure displacement of flowing perfluorocarbon microbubbles in a catheter. This method was able to detect lower flow rates than other CSF flow measurement methods in the literature and could be used for both an initial evaluation of shunt function as well as a tool for studying CSF flow dynamics over time in patients with hydrocephalus. Additionally, the use of focused ultrasound (FUS) blood brain barrier (BBB) disruption for delivery of imaging contrast agents is presented. First, FUS BBB disruption was used to deliver an oxygen-sensitive two-photon contrast agent in the parenchyma of C57BL/6 mice. Both fluorescence and phosphorescence signal from the dye were detectable in the extravascular space after sonication. Then, the delivery of photoacoustic (PA) gold nanorods (AuNRs) via FUS BBB disruption was demonstrated, though further parameter optimization will be necessary. Finally, a possible PA contrast agents for Alzheimer’s Disease was tested. Antibodies for beta-amyloid were conjugated to gold nanoparticles and the conjugated nanoparticles were tested with synthetic peptides and in AD tissue samples. These studies showed that the nanoparticles could specifically bind to synthetic peptides, though electrostatic interactions with the surface the peptides were deposited on complicated interpretation of specificity of the particles. The results of the overall studies indicate that, with the increase in demand for affordable, non-invasive methods for brain imaging and, more broadly, neuroscience, there are numerous potential applications for ultrasound-based techniques.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Emelianov, Stanislav Y. (advisor), Aglyamov, Salavat (committee member), Tunnell, James (committee member), Xie, Chong (committee member).
Subjects/Keywords: Biomedical imaging; Ultrasound; Photoacoustics; Brain imaging; Blood brain barrier; Focused ultrasound; Alzheimer's; Hydrocephalus; Stroke
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
-7772-6051. (2017). Applications of ultrasound and photoacoustics in the central nervous system. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/60433
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-7772-6051. “Applications of ultrasound and photoacoustics in the central nervous system.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/60433.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-7772-6051. “Applications of ultrasound and photoacoustics in the central nervous system.” 2017. Web. 20 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-7772-6051. Applications of ultrasound and photoacoustics in the central nervous system. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/60433.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-7772-6051. Applications of ultrasound and photoacoustics in the central nervous system. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://hdl.handle.net/2152/60433
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
18.
Tom, William James.
Focusing light within turbid media with virtual aperture culling of the eigenmodes of a resonator.
Degree: PhD, Biomedical Engineering, 2012, University of Texas – Austin
URL: http://hdl.handle.net/2152/19998
► Virtual aperture culling of the eigenmodes of a resonator (VACER) is a technique to focus light within turbid media at arbitrary locations. A seed pulse…
(more)
▼ Virtual aperture culling of the eigenmodes of a resonator (VACER) is a technique to focus light within turbid media at arbitrary locations. A seed pulse of light is directed through a phase-conjugate mirror (PCM) into a turbid medium. Though much of the light may be lost, any light which reaches the second PCM is phase conjugated and thus returned to the first PCM where the light will be phase conjugated again. Amplification by the PCMs can prevent decay of the light cycling between the PCMs. Introducing a mechanism which filters light based on position enables attenuation of the modes not traveling through the center of the virtual aperture resulting in a focusing of light at the center of the virtual aperture. The seed pulse and the positioning of the PCMs on opposite sides of the virtual aperture ensure that modes cannot bypass the virtual aperture. Magnetic fields and ultrasound waves are potential means for implementation of a virtual aperture. Generally, only weak filtration mechanisms like magnetic fields and ultrasound waves are innocuous to turbid media. Fortunately, weak effects can strongly cull modes in VACER because the filtration mechanism affects the modes during each pass between PCMs and the modes compete. A combination of theory and computational modeling prove that sound physical principles underlie VACER. Moreover, computational modeling reveals how mode overlap, the seed pulse, and other variables impact VACER performance. Good experimental performance is predicted.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Downer, Michael (committee member), Emelianov, Stanislav (committee member), Milner, Thomas E (committee member), Rylander, Henry G (committee member).
Subjects/Keywords: Biomedical optics; Lasers; Mode competition; Multiple scattering; Phase conjugation; Turbid media
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Tom, W. J. (2012). Focusing light within turbid media with virtual aperture culling of the eigenmodes of a resonator. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/19998
Chicago Manual of Style (16th Edition):
Tom, William James. “Focusing light within turbid media with virtual aperture culling of the eigenmodes of a resonator.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/19998.
MLA Handbook (7th Edition):
Tom, William James. “Focusing light within turbid media with virtual aperture culling of the eigenmodes of a resonator.” 2012. Web. 20 Jan 2021.
Vancouver:
Tom WJ. Focusing light within turbid media with virtual aperture culling of the eigenmodes of a resonator. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/19998.
Council of Science Editors:
Tom WJ. Focusing light within turbid media with virtual aperture culling of the eigenmodes of a resonator. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/19998
University of Texas – Austin
19.
Parthasarathy, Ashwin Bharadwaj.
Quantitative cerebral blood flow measurement with Multi Exposure Speckle Imaging.
Degree: PhD, Biomedical Engineering, 2010, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2010-05-996
► Cerebral blood flow (CBF) measures are central to the investigation of ischemic strokes, spreading depressions, functional and neuronal activation. Laser Speckle Contrast Imaging (LSCI) is…
(more)
▼ Cerebral blood flow (CBF) measures are central to the investigation of ischemic strokes, spreading depressions, functional and neuronal activation. Laser Speckle Contrast Imaging (LSCI) is an optical imaging technique that has been used to obtain CBF measures in vivo at high spatial and temporal resolutions, by quantifying the localized spatial blurring of backscattered coherent light induced by blood flow. Despite being widely used for biomedical applications, LSCI's critical limitations such as its tendency to underestimate large flow changes and its inability to accurately estimate CBF through a thinned skull have not been overcome. This dissertation presents a new Multi Exposure Speckle Imaging (MESI) technique that combines a new instrument and mathematical model to overcome these limitations. Additionally, in a pilot clinical study, an adapted neurosurgical microscope was used to obtain intra-operative LSCI images of CBF in humans. The MESI instrument accurately estimates experimental constants by imaging backscattered speckles over a wide range of the camera's exposure durations. The MESI mathematical model helps account for light that has scattered from both static and moving particles. In controlled flow experiments using tissue simulating phantoms, the MESI technique was found to estimate large changes in flow accurately and the estimates of flow changes were found to be unaffected by the presence of static particles in these phantoms. In an in vivo experiment in which the middle cerebral artery in mice was occluded to induce ~100% reduction in CBF, not only was the reduction in CBF accurately estimated by the MESI technique but these estimates of CBF changes were found to be unaffected by the presence of a thinned skull. The validity of statistical models used to derive the MESI mathematical model was confirmed using in vivo dynamic light scattering (DLS) measurements of CBF in mice. The MESI technique's potential to estimate absolute values of CBF in vivo was demonstrated by comparing CBF estimates obtained using the MESI technique to DLS measurements. The MESI technique's ability to measure CBF changes quantitatively through a thinned skull makes it particularly useful in chronic and long term studies leading to the development of better, more accurate stroke models.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Milner, Thomas (committee member), Tunnell, James (committee member), Emelianov, Stanislav (committee member), Fox, Douglas (committee member).
Subjects/Keywords: Laser Speckle Contrast Imaging; Multi Exposure Speckle Imaging; Optical blood flow measurements; LSCI; MESI; Cerebral blood flow; Ischemic stroke; Speckle spectroscopy; Dynamic Light Scattering; Intra-operative imaging
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Parthasarathy, A. B. (2010). Quantitative cerebral blood flow measurement with Multi Exposure Speckle Imaging. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2010-05-996
Chicago Manual of Style (16th Edition):
Parthasarathy, Ashwin Bharadwaj. “Quantitative cerebral blood flow measurement with Multi Exposure Speckle Imaging.” 2010. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/ETD-UT-2010-05-996.
MLA Handbook (7th Edition):
Parthasarathy, Ashwin Bharadwaj. “Quantitative cerebral blood flow measurement with Multi Exposure Speckle Imaging.” 2010. Web. 20 Jan 2021.
Vancouver:
Parthasarathy AB. Quantitative cerebral blood flow measurement with Multi Exposure Speckle Imaging. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2010. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/ETD-UT-2010-05-996.
Council of Science Editors:
Parthasarathy AB. Quantitative cerebral blood flow measurement with Multi Exposure Speckle Imaging. [Doctoral Dissertation]. University of Texas – Austin; 2010. Available from: http://hdl.handle.net/2152/ETD-UT-2010-05-996
University of Texas – Austin
20.
Ponticorvo, Adrien.
Novel optical techniques for imaging oxygen and other hemodynamic parameters during physiological events.
Degree: PhD, Biomedical Engineering, 2010, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2010-12-2044
► This dissertation presents the development and use of a novel optical imaging system capable of monitoring changes in blood flow, oxygenated hemoglobin, deoxygenated hemoglobin, and…
(more)
▼ This dissertation presents the development and use of a novel optical imaging system capable of monitoring changes in blood flow, oxygenated hemoglobin, deoxygenated hemoglobin, and absolute pO₂ in the brain. There are several imaging modalities capable of monitoring these parameters separately. Laser speckle contrast imaging (LSCI) and multi-spectral reflectance imaging (MSRI) have been used to monitor relative blood flow and hemoglobin changes respectively. Phosphorescence quenching, while not typically used for imaging, is capable of noninvasive measurements of pO₂. Combining these three techniques has led to the development of an imaging system that could ultimately lead to a better understanding of brain physiology. By combining techniques such as LSCI and MSRI, it becomes possible to estimate the cerebral metabolic rate of oxygen (CMRO₂), an important indicator of neuronal function. It is equally important to understand absolute pO₂ levels so that oxygen metabolism can be examined in context. Integrating phosphorescence quenching and a spatial light modulator into the imaging system allowed absolute pO₂ to be simultaneously measured in distinct regions. This new combined system was used to investigate pathophysiological conditions such as cortical spreading depression (CSD) and ischemia. The observed hemodynamic changes associated with these events were largely dictated by baseline oxygen levels and varied significantly in different regions. This finding highlighted the importance of having a system capable of monitoring hemodynamic changes and absolute pO₂ simultaneously while maintaining enough spatial resolution to distinguish the changes in different regions. It was found that animals with low baseline pO₂ were unable to deliver enough oxygen to the brain during events like CSD because of the high metabolic demand. In order for this technique to become more prevalent among researchers, it is essential to make it cost effective and simple to use. This was accomplished by replacing the expensive excitation sources with cheaper light emitting diodes (LEDs) and redesigning the software interface so that it was easier to control the entire device. The final system shows the potential to become a key tool for researchers studying the role of absolute pO₂ and other hemodynamic parameters during pathophysiological conditions such as CSD and ischemia.
Advisors/Committee Members: Dunn, Andrew Kenneth, 1970- (advisor), Jones, Theresa (committee member), Ress, David (committee member), Rylander, Grady (committee member), Tunnell, James (committee member).
Subjects/Keywords: Optical imaging; Oxygen tension; Blood flow; Hemoglobin; MSRI; LSCI; Multi-spectral reflectance imaging; Laser speckle contrast imaging
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Ponticorvo, A. (2010). Novel optical techniques for imaging oxygen and other hemodynamic parameters during physiological events. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2010-12-2044
Chicago Manual of Style (16th Edition):
Ponticorvo, Adrien. “Novel optical techniques for imaging oxygen and other hemodynamic parameters during physiological events.” 2010. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/ETD-UT-2010-12-2044.
MLA Handbook (7th Edition):
Ponticorvo, Adrien. “Novel optical techniques for imaging oxygen and other hemodynamic parameters during physiological events.” 2010. Web. 20 Jan 2021.
Vancouver:
Ponticorvo A. Novel optical techniques for imaging oxygen and other hemodynamic parameters during physiological events. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2010. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/ETD-UT-2010-12-2044.
Council of Science Editors:
Ponticorvo A. Novel optical techniques for imaging oxygen and other hemodynamic parameters during physiological events. [Doctoral Dissertation]. University of Texas – Austin; 2010. Available from: http://hdl.handle.net/2152/ETD-UT-2010-12-2044
University of Texas – Austin
21.
Starosta, Matthew Samuel, 1981-.
Three-dimensional computation of light scattering by multiple biological cells.
Degree: PhD, Electrical and Computer Engineering, 2010, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2010-05-941
► This work presents an investigation into the optical scattering of heterogeneous cells with an application to two-photon imaging, optical scattering measurements and STED imaging. Using…
(more)
▼ This work presents an investigation into the optical scattering of heterogeneous cells with an application to two-photon imaging, optical scattering measurements and STED imaging. Using the finite difference time-domain (FDTD) method, the full-wave scattering by many cells containing multiple organelles with varying indices of refraction is computed. These simulations were previously limited to single cells for reasons of computational cost. A superposition approximation that uses the coherent linear superposition of FDTD-determined farfield scattering patterns of small numbers of cells to estimate the scattering from a larger tissue was developed and investigated. It was found that for the approximation to be accurate, the scattering sub-problems must at minimum extend along the incident field propagation axis for the full depth of the tissue, preserving the scattering that takes place in the direction of propagation. The FDTD method was used to
study the scattering effects of multiple inhomogeneous cells on the propagation of a focused Gaussian beam with an application to two-photon imaging. It was found that scattering is mostly responsible for the reduction in two-photon fluorescence signal as depth is increased. It was also determined that for the chosen beam parameters and the cell and organelle configurations used, the nuclei are the dominant scatterers. FDTD was also utilized in an investigation of cellular scattering effects on the propagation of a common depletion beam used in STED microscopy and how scattering impacts the image obtained with a STED microscope. An axial doughnut beam was formulated and implemented in FDTD simulations, along with a corresponding focused Gaussian beam to simulate a fluorescence excitation beam. It was determined that the depletion beam will maintain a well-defined axial null in spite of scattering, although scattering will reduce the resulting fluorescence signal with focal
depth.
Advisors/Committee Members: Pearce, John A., 1946- (advisor), Dunn, Andrew Kenneth, 1970- (advisor), Thomas, Robert J. (committee member), Milner, Thomas E. (committee member), Wilson, Preston S. (committee member), Ling, Hao (committee member).
Subjects/Keywords: Tissue optics; Optical propagation; Computational electromagnetics; Finite-difference time-domain
Record Details
Similar Records
Cite
Share »
Record Details
Similar Records
Cite
« Share
❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Starosta, Matthew Samuel, 1. (2010). Three-dimensional computation of light scattering by multiple biological cells. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2010-05-941
Chicago Manual of Style (16th Edition):
Starosta, Matthew Samuel, 1981-. “Three-dimensional computation of light scattering by multiple biological cells.” 2010. Doctoral Dissertation, University of Texas – Austin. Accessed January 20, 2021.
http://hdl.handle.net/2152/ETD-UT-2010-05-941.
MLA Handbook (7th Edition):
Starosta, Matthew Samuel, 1981-. “Three-dimensional computation of light scattering by multiple biological cells.” 2010. Web. 20 Jan 2021.
Vancouver:
Starosta, Matthew Samuel 1. Three-dimensional computation of light scattering by multiple biological cells. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2010. [cited 2021 Jan 20].
Available from: http://hdl.handle.net/2152/ETD-UT-2010-05-941.
Council of Science Editors:
Starosta, Matthew Samuel 1. Three-dimensional computation of light scattering by multiple biological cells. [Doctoral Dissertation]. University of Texas – Austin; 2010. Available from: http://hdl.handle.net/2152/ETD-UT-2010-05-941
. 
Open Access Theses and Dissertations
