You searched for +publisher:"University of Texas – Austin" +contributor:("Tunnell, James").
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University of Texas – Austin
1.
Puvanakrishnan, Priyaveena.
Near-infrared narrowband imaging of tumors using gold nanoparticles.
Degree: PhD, Biomedical Engineering, 2011, University of Texas – Austin
URL: http://hdl.handle.net/2152/14362 
► A significant challenge in the surgical resection of tumors is accurate identification of tumor margins. Current methods for margin detection are time-intensive and often result…
(more)
▼ A significant challenge in the surgical resection of tumors is accurate identification of tumor margins. Current methods for margin detection are time-intensive and often result in incomplete tumor excision and recurrence of disease. The objective of this project was to develop a near-infrared narrowband imaging (NIR NBI) system to image tumor and its margins in real-time during surgery utilizing the contrast provided by gold nanoparticles (GNPs). NIR NBI images narrow wavelength bands to enhance contrast from plasmonic particles in a widefield, portable and non-contact device that is clinically compatible for real-time tumor margin demarcation. GNPs have recently gained significant traction as nanovectors for combined imaging and photothermal therapy of tumors. Delivered systemically, GNPs preferentially accumulate at the tumor site via the enhanced permeability and retention effect, and when irradiated with NIR light, produce sufficient heat to treat tumor tissue. The NIR NBI system consists of 1) two LED's: green (530 nm) and NIR (780 nm) LED for illuminating the blood vessels and GNP, respectively, 2) a filter wheel for wavelength selection, and 3) a CCD to collect reflected light from the sample. The NIR NBI system acquires and processes images at a rate of at least 6 frames per second. We have developed custom control software with a graphical user interface that handles both image acquisition and processing/display in real-time. We used mice with a subcutaneous tumor xenograft model that received intravenous administration and topical administration of gold nanoshells and gold nanorods. We determined the GNP's distribution and accumulation pattern within tumors using NIR NBI. Ex vivo NIR NBI of tumor xenografts accumulated with GNPs delivered systemically, demonstrated a highly heterogeneous distribution of GNP within the tumor with higher accumulation at the cortex. GNPs were observed in unique patterns surrounding the perivascular region. The GNPs clearly defined the tumor while surrounding normal tissue did not indicate the presence of particles. In addition, we present results from NBI of tumors that received topical delivery of conjugated GNPs. We determined that tumor labeling using topical delivery approach resulted in a more homogenous distribution of GNPs compared to the systemic delivery approach. Finally, we present results from the on-going in vivo tumor margin imaging studies using NIR NBI. Our results demonstrate the feasibility of NIR NBI in demarcating tumor margins during surgical resection and potentially guiding photo-thermal ablation of tumors.
Advisors/Committee Members: Tunnell, James W. (advisor).
Subjects/Keywords: Gold nanoparticles; Narrow-band imaging; Pancreatic cancer; Breast cancer
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APA (6th Edition):
Puvanakrishnan, P. (2011). Near-infrared narrowband imaging of tumors using gold nanoparticles. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/14362
Chicago Manual of Style (16th Edition):
Puvanakrishnan, Priyaveena. “Near-infrared narrowband imaging of tumors using gold nanoparticles.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/14362.
MLA Handbook (7th Edition):
Puvanakrishnan, Priyaveena. “Near-infrared narrowband imaging of tumors using gold nanoparticles.” 2011. Web. 17 Jan 2021.
Vancouver:
Puvanakrishnan P. Near-infrared narrowband imaging of tumors using gold nanoparticles. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/14362.
Council of Science Editors:
Puvanakrishnan P. Near-infrared narrowband imaging of tumors using gold nanoparticles. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/14362
University of Texas – Austin
2.
Hennessy, Richard J.
Depth resolved diffuse reflectance spectroscopy.
Degree: PhD, Biomedical Engineering, 2015, University of Texas – Austin
URL: http://hdl.handle.net/2152/30340
► This dissertation focuses on the development of computational models and algorithms related to diffuse reflectance spectroscopy. Specifically, this work aims to advance diffuse reflectance spectroscopy…
(more)
▼ This dissertation focuses on the development of computational models and algorithms related to diffuse reflectance spectroscopy. Specifically, this work aims to advance diffuse reflectance spectroscopy to a technique that is capable of measuring depth dependent properties in tissue.
First, we introduce the Monte Carlo lookup table (MCLUT) method for extracting optical properties from diffuse reflectance spectra. Next, we extend this method to a two-layer tissue geometry so that it can extract depth dependent properties in tissue. We then develop a computational model that relates photon sampling depth to optical properties and probe geometry. This model can be used to aid in design of application specific diffuse reflectance probes. In order to provide justification for using a two-layer model for extracting tissue properties, we show that the use of a one-layer model can lead to significant errors in the extracted optical properties. Lastly, we use our two-layer MCLUT model and a probe that was designed based on our sampling depth model to extract tissue properties from the skin of 80 subjects at 5 anatomical locations. The results agree with previously published values for skin properties and show that can diffuse reflectance spectroscopy can be used to measured depth dependent properties in tissue.
Advisors/Committee Members: Markey, Mia Kathleen (advisor), Tunnell, James W. (advisor).
Subjects/Keywords: Diffuse reflectance spectroscopy; Biomedical optics; Computational modeling; Monte Carlo simulation
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APA (6th Edition):
Hennessy, R. J. (2015). Depth resolved diffuse reflectance spectroscopy. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/30340
Chicago Manual of Style (16th Edition):
Hennessy, Richard J. “Depth resolved diffuse reflectance spectroscopy.” 2015. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/30340.
MLA Handbook (7th Edition):
Hennessy, Richard J. “Depth resolved diffuse reflectance spectroscopy.” 2015. Web. 17 Jan 2021.
Vancouver:
Hennessy RJ. Depth resolved diffuse reflectance spectroscopy. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2015. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/30340.
Council of Science Editors:
Hennessy RJ. Depth resolved diffuse reflectance spectroscopy. [Doctoral Dissertation]. University of Texas – Austin; 2015. Available from: http://hdl.handle.net/2152/30340
University of Texas – Austin
3.
-3001-4994.
An arborizing, multiport catheter for maximizing drug distribution in the brain via convection enhanced delivery.
Degree: PhD, Biomedical Engineering, 2018, University of Texas – Austin
URL: http://hdl.handle.net/2152/69265
► Glioblastoma (GBM) is a high-grade malignant glioma with a mortality rate that exceeds 95% despite over eight decades of medical research dedicated to improve outcomes.…
(more)
▼ Glioblastoma (GBM) is a high-grade malignant glioma with a mortality rate that exceeds 95% despite over eight decades of medical research dedicated to improve outcomes. GBM is extremely difficult to treat and practically incurable with standard treatment involving surgical resection, radiation, concomitant and/or adjuvant chemotherapy. Therefore, convection enhanced delivery (CED) was developed to improve therapeutic outcomes. CED involves intraparenchymal delivery of drugs into diseased tissue via a small catheter. CED has proven to bypass the blood brain barrier and achieve better drug distribution than diffusion-based therapies. Nevertheless, the large volumes necessary to target entire tumors and peritumor volumes have been previously unachievable with currently-available catheters. This dissertation describes the development of a multiport, arborizing catheter designed specifically for improving drug distribution in the brain. The performance of early-stage arborizing catheter prototypes was compared to single-port catheters in infusion studies using agarose brain phantoms. Volume dispersed (V [subscript d]) and mean distribution ratios (V [subscript d] :V [subscript i]) were quantified and compared between the two catheters. The arborizing catheter produced higher V [subscript d] values; however, it did not exhibit the greatest V [subscript d] :V [subscript i], likely due to overlapping distribution volumes from the multiple individual ports. Following infusion in brain phantoms, a biotransport study of the arborizing catheter was conducted using a multiphasic finite element framework. The model was used to predict dispersion volume of a solute in a permeable hyperelastic solid matrix as a function of separation distance between adjacent ports. Results show that increasing port distance can increase V [subscript d]; however, infusion time also increases significantly with greater port distance. One way to mitigate increased infusion times is to employ higher infusion flow rates. Finally, the performance of improved arborizing catheters was compared to reflux-preventing single-port catheters in excised pig brains. CT scans were used to quantify V [subscript d] and V [subscript d] :V [subscript i] of infused iohexol (contrast-enhancing agent). The average volume dispersed for the arborizing catheter was 5.8 times greater than the single-port catheter. Mean distribution ratios for both catheters were similar. Using the multiple ports of the arborizing catheter, high V [subscript d] was achieved at a low infusion rate with negligible reflux. Given that previous attempts of CED reported poor drug distribution, the arborizing catheter may help overcome the limitations of CED.
Advisors/Committee Members: Rylander, Christopher Grady, 1978- (advisor), Rausch, Manuel K (committee member), Rossmeisl, John (committee member), Tunnell, James (committee member), Yankeelov, Thomas (committee member).
Subjects/Keywords: Convection enhanced delivery; Glioblastoma; Biphasic finite elements; Infusions; Agarose tissue phantoms
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APA (6th Edition):
-3001-4994. (2018). An arborizing, multiport catheter for maximizing drug distribution in the brain via convection enhanced delivery. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/69265
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-3001-4994. “An arborizing, multiport catheter for maximizing drug distribution in the brain via convection enhanced delivery.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/69265.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-3001-4994. “An arborizing, multiport catheter for maximizing drug distribution in the brain via convection enhanced delivery.” 2018. Web. 17 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-3001-4994. An arborizing, multiport catheter for maximizing drug distribution in the brain via convection enhanced delivery. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/69265.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-3001-4994. An arborizing, multiport catheter for maximizing drug distribution in the brain via convection enhanced delivery. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://hdl.handle.net/2152/69265
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
4.
Chen, Peng, active 21st century.
Immunomagnetic circulating tumor cells (CTCs) detection at small scale : multiphysical modeling, thin-film magnets and cancer screening.
Degree: PhD, Biomedical Engineering, 2014, University of Texas – Austin
URL: http://hdl.handle.net/2152/31287
► Circulating tumor cells (CTCs) are the cells that are shed from a primary tumor into the vasculature and circulate in the bloodstream. CTCs may trigger…
(more)
▼ Circulating tumor cells (CTCs) are the cells that are shed from a primary tumor into the vasculature and circulate in the bloodstream. CTCs may trigger cancer metastasis, which leads to most cancer-related deaths. CTCs are widely studied due to their value in cancer diagnosis, prognosis, and oncology studies. The major challenges with CTCs lie in their extremely low concentration in blood, thus requiring an effective enriching system to enable downstream analyses. The immunomagnetic assay has proved to be a promising CTC detection tool with high sensitivity and throughput. Key factors related to the immunomagnetic assay include the capture rate, which indicates the sensitivity, and distributions of target cells after capture, which impact the cell integrity and other biological properties. In this dissertation, we build a sedimentation model, a partial viscosity model, and a cell-tracking model to address the principle of the immunomagnetic cell separation. We examine the channel orientations and determine the favorable inverted condition. In addition, we develop a micromagnet approach to modulate the in-channel magnetic field toward enhanced cell detection and distribution. Through numerical studies, we calculate the magnetic field generated by the thin-film micromagnets, determine its effective ranges, and demonstrate its value in optimizing cell distribution. In the experimental demonstration, we present two types of micromagnets based on e-beam Ni deposition and inkjet printing technology, respectively. In the screening experiments, the Ni micromagnet integrated system achieves over 97% capture rate. It shows a 14% increase in capture rate, and a 14% improvement in distribution uniformity compared with plain slides. We also successfully isolate CTCs from metastatic cancer patients with the micromagnet assay. The inkjet-printed patterns yield a similarly high capture rate of 103%. With the pixel permanent magnet array, the inkjet patterns further increase the distribution uniformity for 20%. The proposed models lay the theoretical foundations for future modification of the immunomagnetic assay, and the micromagnet-integrated system provides a promising tool for translational applications in cancer diagnose and clinical cancer management.
Advisors/Committee Members: Zhang, Xiaojing, Ph. D. (advisor), Yeh, Tim H. C. (advisor), Hoshino, Kazunori (committee member), Tunnell, James W (committee member), Jiang, Ning (committee member).
Subjects/Keywords: Circulating tumor cells; Immunomagnetic assay; Micromagnet; Cell separation
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APA (6th Edition):
Chen, Peng, a. 2. c. (2014). Immunomagnetic circulating tumor cells (CTCs) detection at small scale : multiphysical modeling, thin-film magnets and cancer screening. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/31287
Chicago Manual of Style (16th Edition):
Chen, Peng, active 21st century. “Immunomagnetic circulating tumor cells (CTCs) detection at small scale : multiphysical modeling, thin-film magnets and cancer screening.” 2014. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/31287.
MLA Handbook (7th Edition):
Chen, Peng, active 21st century. “Immunomagnetic circulating tumor cells (CTCs) detection at small scale : multiphysical modeling, thin-film magnets and cancer screening.” 2014. Web. 17 Jan 2021.
Vancouver:
Chen, Peng a2c. Immunomagnetic circulating tumor cells (CTCs) detection at small scale : multiphysical modeling, thin-film magnets and cancer screening. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/31287.
Council of Science Editors:
Chen, Peng a2c. Immunomagnetic circulating tumor cells (CTCs) detection at small scale : multiphysical modeling, thin-film magnets and cancer screening. [Doctoral Dissertation]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/31287
University of Texas – Austin
5.
-3544-7227.
Rapid wide-field imaging of soft-tissue microstructure.
Degree: PhD, Biomedical Engineering, 2019, University of Texas – Austin
URL: http://hdl.handle.net/2152/72693
► Tissue microstructure is pivotal in determining the function, behavior, and disease state of biological tissues. Histology and advanced optical techniques are commonly used to examine…
(more)
▼ Tissue microstructure is pivotal in determining the function, behavior, and disease state of biological tissues. Histology and advanced optical techniques are commonly used to examine the cellular, extracellular, and subcellular constituents that define tissue microstructure. However, these techniques frequently require tedious and destructive tissue preparations and lengthy imaging times, or have limited fields of view. Therefore, it is challenging to study soft-tissue microstructure within the macroscopic spatial and temporal context of tissue- and organ-level function. Wide-field imaging techniques provide a non-destructive alternative to rapidly assess tissue microstructure across macroscopic fields of view. Rather than resolving microstructure directly, these techniques are sensitive to light-scattering characteristics of tissue that indicate the underlying microstructure. This dissertation develops light-scattering models to interpret tissue microstructure from light-scattering across macroscopic fields of view rapidly and non-destructively.
The first half of the dissertation uses spatial frequency domain imaging (SFDI) to quantify the sub-diffuse light-scattering characteristics of tissues that are intrinsically linked to microstructure. It then introduces a novel empirical model which allows rapid fitting of SFDI data and is sensitive to changes in microparticle size. This technique is then demonstrated as a potential surgical guidance tool for Mohs Micrographic Surgery by rapidly and non-destructively demarcating tumor boundaries in skin biopsies. The imaging and processing speeds achieved with this technique can improve clinical workflows, particularly tissue-conserving surgical procedures, which are currently hindered by the time necessary to determine tumor boundaries using histopathology. Improvements to this technique by use of higher spatial frequencies are also considered.
The second section investigates polarization-dependent scattering in tissues that is a result of collagen fiber microstructure. An experimentally-validated computational model is developed to allow direct conversion of polarized-light measurements into absolute measures of collagen fiber alignment in tissues. Furthermore, a combined polarized light SFDI system (pSFDI) is demonstrated to measure distinct fiber alignments in multi-layered tissue samples. The increased speed and versatility of this system is employed to map wide-field microfiber kinematics during mechanical tissue deformation. This technique enables direct examination of the contributions of local fiber kinematics to tissue- and organ-level scales of growth and remodeling.
Advisors/Committee Members: Tunnell, James W. (advisor), Sacks, Michael S. (advisor), Milner, Thomas E (committee member), Ravi-Chandar, Krishnaswamy (committee member).
Subjects/Keywords: Light scattering; Biomedical optics; Tissue optics; Mie theory; Polarized light; Tissue structure; Microstructure; Imaging; Wide-field; Spatial frequency domain
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APA ·
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APA (6th Edition):
-3544-7227. (2019). Rapid wide-field imaging of soft-tissue microstructure. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/72693
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-3544-7227. “Rapid wide-field imaging of soft-tissue microstructure.” 2019. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/72693.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-3544-7227. “Rapid wide-field imaging of soft-tissue microstructure.” 2019. Web. 17 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-3544-7227. Rapid wide-field imaging of soft-tissue microstructure. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2019. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/72693.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-3544-7227. Rapid wide-field imaging of soft-tissue microstructure. [Doctoral Dissertation]. University of Texas – Austin; 2019. Available from: http://hdl.handle.net/2152/72693
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
6.
Kim, Ki Hyun.
Development of high-speed imaging techniques for C. elegans nervous system studies.
Degree: PhD, Electrical and Computer Engineering, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/68306
► We report high-speed imaging techniques for C. elegans nervous systems studies. We introduce C. elegans, the main model organism in this dissertation, and neuroscientific and…
(more)
▼ We report high-speed imaging techniques for C. elegans nervous systems studies.
We introduce C. elegans, the main model organism in this dissertation, and neuroscientific and biomedical studies using C. elegans involving calcium imaging, nerve regeneration, and drug screening. We review technologies including confocal microscopy and microfluidic devices used in the neuroscientific and biomedical studies
We discuss development of a high-speed laser scanning confocal microscope capable of flexible control of imaging conditions, fast imaging speed, and large field-of-view. We provides the design principles used in the development of the confocal microscope including the optical, electrical, and software implementation, and the details of the confocal microscope we built based on the design principles. We present the performance characterization of the confocal microscope, then a few sample images obtained with the confocal microscope.
We present development of time-lapse volumetric confocal imaging of whole animal C. elegans Ca²⁺ dynamics. We provide the design of the time-lapse volumetric confocal imaging system including a microfluidic device to accommodate the whole animal within the field-of-view of the imaging system. We examine the feasibility of the volumetric confocal imaging of a whole animal, and demonstrate imaging of the whole animal C. elegans neurons’ response to NaCl within a 630 × 150 × 25 μm³ volume at 2 Hz rate.
We report a high-throughput automated imaging platform for C. elegans nerve regeneration study. We describe the design of the automated imaging platform and the automation flow, and characterizes the performance of the platform. The imaging platform can obtain high-resolution 3D confocal images of 20 animals in 10 minutes. We show sample images of C. elegans anterior lateral microtubule nerve regeneration examples acquired via the automated imaging platform.
We demonstrate a planar laser activated neuronal scanning platform (PLANS), a high-throughput animal examination system for drug screening. We explain the construction of PLANS involving the optics, the microfluidic device, and the electronics. The PLANS system can scan an animal in less than 5 ms with a spatial sampling resolution of 3 μm FWHM. We show sample scanning results of a Huntington’s disease model of C. elegans.
We summarize the studies discussed in this dissertation, and suggest relevant future research to follow up on the studies.
Advisors/Committee Members: Ben-Yakar, Adela (advisor), Yu, Edward (committee member), Tunnell, James (committee member), Pierce-Shimomura, Jonathan (committee member), Bank, Seth (committee member).
Subjects/Keywords: Confocal microscopy; Instrumentation; Biomedical
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APA ·
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APA (6th Edition):
Kim, K. H. (2016). Development of high-speed imaging techniques for C. elegans nervous system studies. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/68306
Chicago Manual of Style (16th Edition):
Kim, Ki Hyun. “Development of high-speed imaging techniques for C. elegans nervous system studies.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/68306.
MLA Handbook (7th Edition):
Kim, Ki Hyun. “Development of high-speed imaging techniques for C. elegans nervous system studies.” 2016. Web. 17 Jan 2021.
Vancouver:
Kim KH. Development of high-speed imaging techniques for C. elegans nervous system studies. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/68306.
Council of Science Editors:
Kim KH. Development of high-speed imaging techniques for C. elegans nervous system studies. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/68306
University of Texas – Austin
7.
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
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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 17, 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. 17 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 17].
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
8.
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
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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 17, 2021.
http://hdl.handle.net/2152/38225.
MLA Handbook (7th Edition):
Davis, Mitchell Alan. “Three dimensional simulation of functional neuro-vascular imaging.” 2014. Web. 17 Jan 2021.
Vancouver:
Davis MA. Three dimensional simulation of functional neuro-vascular imaging. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Jan 17].
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
9.
Silbaugh, Dorothy Ann.
Fluorescent silicon nanocrystals for bioimaging.
Degree: PhD, Materials Science and Engineering, 2017, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/8219
► Quantum dots have been used as alternatives to organic dyes for fluorescence imaging because they are resistant to photobleaching, exhibit strong response to two-photon excitation,…
(more)
▼ Quantum dots have been used as alternatives to organic dyes for fluorescence imaging because they are resistant to photobleaching, exhibit strong response to two-photon excitation, and can be conjugated to a wide variety of targeting molecules. Silicon (Si) nanocrystal quantum dots in particular exhibit bright, size-dependent emission with visible to near infrared wavelengths and are biocompatible, making them potentially interesting for in vitro and in vivo bioimaging. Here, Si nanocrystals are studied for imaging applications.
The stability of Si nanocrystal dispersibility and photoluminescence (PL) in aqueous solutions was studied. Hydrophobic Si nanocrystals were dispersed with surfactants to produce colloidally stable and brightly fluorescent dispersions, with PL quantum yields in the range of 3.2% - 6.6%. Hydrophilic Si nanocrystals capped with a ligand containing a terminal carboxylic acid group could be directly dispersed in aqueous environments with quantum yields of up to 9.1% in water. The nanocrystal PL was stable in water for at least one week, however there was a significant loss of PL when the particles were dispersed in biological solutions. The drop in PL was accompanied by surface oxidation and degradation of the nanocrystals. Si nanocrystals incubated with mouse macrophage cells were actively taken up by endocytosis. Cell viability assays indicated that the nanocrystals were not toxic to the macrophages. The Si nanocrystals were bright enough to be imaged within the cells by one-photon and two-photon microscopy. Hydrophilic Si nanocrystals that emit in the near infrared (900-1000 nm) could also be dispersed directly into water, however the emission quantum yields were prohibitively low for imaging applications. Time gated imaging of cells labeled with Si nanocrystals enabled multiplex imaging using optical probes with spectral overlap by separating the PL of organic dyes with short nanosecond lifetimes and Si nanocrystals with long microsecond lifetimes. Finally, biotin bioconjugation was accomplished to Si nanocrystal surfaces, though the conjugation reaction efficiencies were relatively low.
Advisors/Committee Members: Korgel, Brian Allan, 1969- (advisor), Maynard, Jennifer (committee member), Ekerdt, John (committee member), Yu, Guihua (committee member), Tunnell, James (committee member).
Subjects/Keywords: Silicon nanocrystals bioimaging
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APA (6th Edition):
Silbaugh, D. A. (2017). Fluorescent silicon nanocrystals for bioimaging. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/8219
Chicago Manual of Style (16th Edition):
Silbaugh, Dorothy Ann. “Fluorescent silicon nanocrystals for bioimaging.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://dx.doi.org/10.26153/tsw/8219.
MLA Handbook (7th Edition):
Silbaugh, Dorothy Ann. “Fluorescent silicon nanocrystals for bioimaging.” 2017. Web. 17 Jan 2021.
Vancouver:
Silbaugh DA. Fluorescent silicon nanocrystals for bioimaging. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2021 Jan 17].
Available from: http://dx.doi.org/10.26153/tsw/8219.
Council of Science Editors:
Silbaugh DA. Fluorescent silicon nanocrystals for bioimaging. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://dx.doi.org/10.26153/tsw/8219
University of Texas – Austin
10.
Kim, Eun Song.
Sensors and structured beams in optical coherence tomography.
Degree: PhD, Electrical and Computer engineering, 2017, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/3145
► Optical coherence tomography (OCT) is an emerging medical imaging technique that provides images of various tissue structures at micrometer scale resolution. A swept source laser…
(more)
▼ Optical coherence tomography (OCT) is an emerging medical imaging technique that provides images of various tissue structures at micrometer scale resolution. A swept source laser which emits time-varying wavelengths light at a high-speed was developed that greatly improves OCT processing speed and image resolution. This dissertation presents system developments for swept source based OCT. I have designed and demonstrated three different OCT systems that can be used for diagnostic applications. First, I present a common-path OCT system with a cleaved optical fiber as a probe. The system is built as a tactile sensor for implementation in surgical robots. A tactile sensor, often referred to as a force sensor, is a device that is sensitive to applied force or pressure. Since the system has a high sensitivity to pressure and a compact size, the sensor is compatible with the surgical robots field which require fine force control. This new sensor may aid in diagnosing diseased tissue or cells by measuring their Young' s modulus.
Secondly, an Angular/Longitudinal Doppler OCT system (ALD-OCT) was constructed to sense the rotation of an object. Previous work has shown, it is feasible to detect a linearly moving object by Doppler OCT. However, ALD-OCT, OCT utilizes a helical phase shape beam that, has been studied due to its distinct characteristics. An application of using a vortex beam is sensing a rotating object by measuring the angular Doppler shift from the beam reflected off the object. ALD-OCT can utilize depth resolved analysis and be implemented to detect helical shaped particles or the vorticity of blood flows under the skin or in the retina noninvasively.
Lastly, we propose several designs of optical probes for a swept source OCT system. The designs of the GRIN lens bundle probes were presented to demonstrate angled illumination and detection techniques in OCT systems. The beam profiles of the output beams from the probes were analyzed theoretically using ABCD ray matrices. We present a method to measure the beam profile of a sweeping wavelength laser source, which can be applied to measure any optical probes connected to the swept source laser.
Advisors/Committee Members: Milner, Thomas E. (advisor), Valvano, Jonathan W (committee member), Dunn, Andrew (committee member), Tunnell, James (committee member), Daigle, Hugh (committee member).
Subjects/Keywords: Optical coherence tomography
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APA (6th Edition):
Kim, E. S. (2017). Sensors and structured beams in optical coherence tomography. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/3145
Chicago Manual of Style (16th Edition):
Kim, Eun Song. “Sensors and structured beams in optical coherence tomography.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://dx.doi.org/10.26153/tsw/3145.
MLA Handbook (7th Edition):
Kim, Eun Song. “Sensors and structured beams in optical coherence tomography.” 2017. Web. 17 Jan 2021.
Vancouver:
Kim ES. Sensors and structured beams in optical coherence tomography. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2021 Jan 17].
Available from: http://dx.doi.org/10.26153/tsw/3145.
Council of Science Editors:
Kim ES. Sensors and structured beams in optical coherence tomography. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://dx.doi.org/10.26153/tsw/3145
University of Texas – Austin
11.
-9048-7144.
Biophysical basis of skin cancer detection using Raman spectroscopy.
Degree: PhD, Biomedical Engineering, 2020, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/7494
► The goal of this dissertation is to study the potential of Raman spectroscopy in improving the clinical diagnosis of skin cancer, including two main applications:…
(more)
▼ The goal of this dissertation is to study the potential of Raman spectroscopy in improving the clinical diagnosis of skin cancer, including two main applications: noninvasive screening of melanoma skin cancer and surgical margin detection of nonmelanoma skin cancer. Skin cancer is the most common type of malignancy, accounting for over 5.4 million cases and 10 thousand deaths per year in the United States alone. Like most cancers, the current “gold standard” diagnosis relies on biopsy and histopathology, which is invasive, time-consuming, and costly. Moreover, large numbers of benign lesions are biopsied for melanoma diagnosis, resulting in substantial financial burden and patient discomfort. Therefore, an urgent need exists to develop a noninvasive, fast, and accurate method for skin cancer detection. The first part of the dissertation focuses on exploring the biophysical origin of in vivo melanoma detection. Our group has previously reported on the development of a clinical Raman spectroscopy system towards spectral biopsy of skin; however, the biochemical changes that Raman spectroscopy relies on for accurate melanoma diagnosis remained unclear. As a result, we proposed a biophysical inverse model to address this issue. To build the model, we established a custom confocal Raman microscope to extract in situ human skin constituents spanning normal and various diseased states. Our results indicate collagen, elastin, keratin, cell nucleus, triolein, ceramide, melanin, and water are the most important model components. Furthermore, collagen and triolein are the most relevant markers to discriminate malignant melanoma from benign nevi. The second part of the dissertation discusses the biophysical basis of nonmelanoma skin cancer margin delineation. We discovered the diagnostic markers to accurately differentiate tumor from normal skin, which is critical to maximize positive patient outcomes in skin cancer surgery. The biochemical changes derived from our model were highly correlated with histopathological diagnosis. We further demonstrated the feasibility of a superpixel acquisition approach for rapid classification of tumor boundaries in skin biopsies. Our results suggest Raman spectroscopy will be a powerful tool for intraoperative surgical guidance
Advisors/Committee Members: Tunnell, James W. (advisor), Dunn, Andrew K (committee member), Milner, Thomas E (committee member), Fox, Matthew C (committee member).
Subjects/Keywords: Raman spectroscopy; Skin cancer; Tissue diagnostics; Diagnostic markers; Biophysical model; Melanoma; Nonmelanoma; Surgical margin detection
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APA (6th Edition):
-9048-7144. (2020). Biophysical basis of skin cancer detection using Raman spectroscopy. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/7494
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-9048-7144. “Biophysical basis of skin cancer detection using Raman spectroscopy.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://dx.doi.org/10.26153/tsw/7494.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-9048-7144. “Biophysical basis of skin cancer detection using Raman spectroscopy.” 2020. Web. 17 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-9048-7144. Biophysical basis of skin cancer detection using Raman spectroscopy. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Jan 17].
Available from: http://dx.doi.org/10.26153/tsw/7494.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-9048-7144. Biophysical basis of skin cancer detection using Raman spectroscopy. [Doctoral Dissertation]. University of Texas – Austin; 2020. Available from: http://dx.doi.org/10.26153/tsw/7494
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
12.
Bloom, Meghan Jean.
Characterizing treatment induced alterations of the tumor microenvironment towards optimizing therapeutic regimens in cancer.
Degree: PhD, Biomedical Engineering, 2020, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/8355
► It is well recognized that the tumor microenvironment plays a key role in cancer initiation, progression, and response to treatment. Therapies targeted towards the tumor…
(more)
▼ It is well recognized that the tumor microenvironment plays a key role in cancer initiation, progression, and response to treatment. Therapies targeted towards the tumor microenvironment are being introduced in the clinic to be administered alongside chemotherapy and radiation, however, not every patient responds to treatment. The purpose of this dissertation is to characterize modulation of the tumor microenvironment induced by targeted therapies, and build a better understanding of how to exploit these alterations to increase efficacy of developing combination treatments. Our objective is addressed in three parts. First, we quantified temporal alterations in nuclear factor kappa B signaling and downstream gene expression to a small-molecule pathway inhibitor and demonstrated the complexity of altering pathway dynamics for therapeutic gain. Secondly, we characterized changes in innate immune cell infiltration in human epidermal growth factor receptor 2 positive (HER2+) breast cancer after targeted antibody treatment and identified mechanisms of vascular alterations and windows of reduced immune suppression. Lastly, we quantified the effects of radiation and targeted antibody therapy in HER2+ breast cancer and elucidated a potential to reduce radiation dose in this combination regimen. Collectively, the results presented provide valuable insight of how the tumor microenvironment can dictate treatment response and the potential to modulate the tumor microenvironment to enhance therapeutic efficacy
Advisors/Committee Members: Yankeelov, Thomas E. (advisor), Brock, Amy (committee member), Sorace, Anna G (committee member), Tunnell, James W (committee member), Virostko, Jack (committee member).
Subjects/Keywords: Trastuzumab; HER2; Nuclear factor kappa B
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APA (6th Edition):
Bloom, M. J. (2020). Characterizing treatment induced alterations of the tumor microenvironment towards optimizing therapeutic regimens in cancer. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/8355
Chicago Manual of Style (16th Edition):
Bloom, Meghan Jean. “Characterizing treatment induced alterations of the tumor microenvironment towards optimizing therapeutic regimens in cancer.” 2020. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://dx.doi.org/10.26153/tsw/8355.
MLA Handbook (7th Edition):
Bloom, Meghan Jean. “Characterizing treatment induced alterations of the tumor microenvironment towards optimizing therapeutic regimens in cancer.” 2020. Web. 17 Jan 2021.
Vancouver:
Bloom MJ. Characterizing treatment induced alterations of the tumor microenvironment towards optimizing therapeutic regimens in cancer. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2020. [cited 2021 Jan 17].
Available from: http://dx.doi.org/10.26153/tsw/8355.
Council of Science Editors:
Bloom MJ. Characterizing treatment induced alterations of the tumor microenvironment towards optimizing therapeutic regimens in cancer. [Doctoral Dissertation]. University of Texas – Austin; 2020. Available from: http://dx.doi.org/10.26153/tsw/8355
University of Texas – Austin
13.
-0853-2557.
Nonlinear imaging assisted ultrafast laser microsurgery for the treatment of vocal fold scarring.
Degree: PhD, Mechanical engineering, 2015, University of Texas – Austin
URL: http://hdl.handle.net/2152/31548
► Femtosecond laser pulses achieve unrivaled microsurgical precision by developing extremely high peak intensity with relatively low total pulse energy. Despite a wide range of clinical…
(more)
▼ Femtosecond laser pulses achieve unrivaled microsurgical precision by developing extremely high peak intensity with relatively low total pulse energy. Despite a wide range of clinical advantages and applications that have been identified in bench-top studies, clinical development of femtosecond laser microsurgery outside of ophthalmology has remained in its infancy. The lack of a means to flexibly deliver the high-intensity laser light to areas of interest and guide it with suitable precision has constituted a serious hurdle to further clinical development. In response, this dissertation has detailed my research and development of table-top systems and the fiber-coupled femtosecond laser microsurgery scalpel to treat vocal fold scarring which does not have any reliable treatment in the clinic. This dissertation focuses on laser ablation and nonlinear imaging parameters for creation of sub-epithelial voids in vocal folds and how these parameters varied in scar tissue using animal models. We specifically investigated the differences in tissue architecture and scattering properties, and their relation to ablation thresholds and bubble lifetime. By using nonlinear imaging, we quantified tissue architecture and bubble dynamics. By developing a new method, we measured the ablation threshold below tissue surface while simultaneously extracting the extinction properties of different tissue layers. Also, we performed in-depth analysis using numerical, analytical, and experimental techniques to understand the limitation of maximum imaging depths with third-harmonic generation microscopy in turbid tissues such as vocal folds compared to two-photon autofluorescence microscopies. Our experimental results revealed that maximum imaging depth improved significantly from 140 µm to 420 µm using THG microscopy at 1552 nm excitation wavelength as compared to TPM at 776 nm. The second part of the dissertation explores developing a novel biomaterialdelivery method to inject and localize PEG 30 biomaterial inside sub-epithelial voids created by ultra-short laser pulses within scarred cheek pouch samples. To demonstrate the feasibility of this technique, we developed a semi-automated system to control and monitor the diffusion of the biomaterial inside scarred hamster cheek pouch samples. We observed a back-flow of the injected biomaterial along the point of injection and this condition prevented localization of the biomaterial at the desired locations without creating any void. In contrast to the biomaterial injection outcomes without any voids, the presence of sub-epithelial voids greatly reduced back-flow at the injection site and resulted in a lasting localization of the injected biomaterial at different locations of the tissue. We also performed a follow-up H&E histology and realized that the location and appearance of the biomaterial correlated well with TPAF and SHG in-situ nonlinear images. Finally, in the third part of the dissertation, we developed a piezo-scanned fiber device for high-speed ultrafast laser microsurgery, with an…
Advisors/Committee Members: Ben-Yakar, Adela (advisor), Murthy, Jayathi (committee member), Hall, Matthew (committee member), Tunnell, James (committee member), Kobler, James (committee member).
Subjects/Keywords: Nonlinear imaging; Vocal fold scarring; Ultrafast laser ablation
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APA (6th Edition):
-0853-2557. (2015). Nonlinear imaging assisted ultrafast laser microsurgery for the treatment of vocal fold scarring. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/31548
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-0853-2557. “Nonlinear imaging assisted ultrafast laser microsurgery for the treatment of vocal fold scarring.” 2015. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/31548.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-0853-2557. “Nonlinear imaging assisted ultrafast laser microsurgery for the treatment of vocal fold scarring.” 2015. Web. 17 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-0853-2557. Nonlinear imaging assisted ultrafast laser microsurgery for the treatment of vocal fold scarring. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2015. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/31548.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-0853-2557. Nonlinear imaging assisted ultrafast laser microsurgery for the treatment of vocal fold scarring. [Doctoral Dissertation]. University of Texas – Austin; 2015. Available from: http://hdl.handle.net/2152/31548
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
14.
-4953-3644.
Optical and structural property mapping of soft tissues using spatial frequency domain imaging.
Degree: PhD, Biomedical engineering, 2015, University of Texas – Austin
URL: http://hdl.handle.net/2152/31345
► Tissue optical properties, absorption, scattering and fluorescence, reveal important information about health, and holds the potential for non-invasive diagnosis and therefore earlier treatment for many…
(more)
▼ Tissue optical properties, absorption, scattering and fluorescence, reveal important information about health, and holds the potential for non-invasive diagnosis and therefore earlier treatment for many diseases. On the other hand, tissue structure determines its function. Studying tissue structural properties helps us better understand structure-function relationship. Optical imaging is an ideal tool to study these tissue properties. However, conventional optical imaging techniques have limitations, such as not being able to quantitatively evaluate tissue absorption and scattering properties and only providing volumetrically averaged quantities with no depth control capability. To better study tissue properties, we integrated spatial frequency domain imaging (SFDI) with conventional reflectance imaging modalities. SFDI is a non-invasive, non-contact wide-field imaging technique which utilizes structured illumination to probe tissues. SFDI imaging is able to accurately quantify tissue optical properties. By adjusting spatial frequency, the imaging depth can be tuned which allows for depth controlled imaging. Especially at high spatial frequency, SFDI reflectance image is more sensitive to tissue scattering property than absorption property. The imaging capability of SFDI allows for studying tissue properties from a whole new perspective. In our study, we developed both benchtop and handheld SFDI imaging systems to accommodate different applications. By evaluating tissue optical properties, we corrected attenuation in fluorescence imaging using an analytical model; and we quantified optical and physical properties of skin diseases. By imaging at high spatial frequency, we demonstrated that absorption in fluorescence imaging can also be reduced because of a reduced imaging depth. This correction can be performed in real-time at 19 frames/second. Furthermore, fibrous structures orientation from the superficial layer can be accurately quantified in a multi-layered sample by limiting imaging depth. Finally, we color rendered SFDI reflectance image at high spatial frequency to reveal structural changes in skin lesions.
Advisors/Committee Members: Tunnell, James W. (advisor), Krishnan, Sunil (committee member), Reichenberg, Jason S (committee member), Yeh, Hsin-Chih (committee member), Sacks, Michael (committee member).
Subjects/Keywords: Spatial frequency domain imaging; Fluorescence imaging; Polarized light imaging; Hyperspectral imaging; Imaging instrument
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APA (6th Edition):
-4953-3644. (2015). Optical and structural property mapping of soft tissues using spatial frequency domain imaging. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/31345
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-4953-3644. “Optical and structural property mapping of soft tissues using spatial frequency domain imaging.” 2015. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/31345.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-4953-3644. “Optical and structural property mapping of soft tissues using spatial frequency domain imaging.” 2015. Web. 17 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-4953-3644. Optical and structural property mapping of soft tissues using spatial frequency domain imaging. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2015. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/31345.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-4953-3644. Optical and structural property mapping of soft tissues using spatial frequency domain imaging. [Doctoral Dissertation]. University of Texas – Austin; 2015. Available from: http://hdl.handle.net/2152/31345
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
15.
-2308-0707.
Scattering angle resolved optical coherence tomography for early retinal detection of Alzheimer’s disease in a murine model.
Degree: PhD, Biomedical Engineering, 2018, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/10902
► Alzheimer’s disease (AD), a debilitating neurodegenerative disease, is becoming more prevalent with an aging population. Early detection of AD is critical to extending healthy lives,…
(more)
▼ Alzheimer’s disease (AD), a debilitating neurodegenerative disease, is becoming more prevalent with an aging population. Early detection of AD is critical to extending healthy lives, but current techniques for AD detection are invasive and cost-prohibitive. The retina is embryonically derived from the forebrain and, with recent mounting evidence that it may reveal markers of brain injury, is considered a “window to the brain.” Early neurodegenerative changes in the brain are likely to be observed in the retina—synaptic failure and shifts in mitochondrial dynamics. Optical imaging techniques could hold the key to non-invasive early detection of AD in the retina since these disruptions may be observed with light. In particular, optical coherence tomography (OCT) retinal imaging offers 3D images of retinal neurons, but the resolution of clinical OCT systems is not fine enough to observe disruptions in the sub-cellular space. Scattering angle resolved (SAR-) OCT, a new method introduced in this work, aims to access sub-resolution scattering properties which could expose fundamental changes in the neurons associated with AD. In this dissertation, a custom SAR-OCT system and new image processing protocols are designed and constructed for murine retinal imaging. Then, three in-vivo studies are conducted using the imaging system to demonstrate its potential use in disease detection. In the first study, which establishes fundamental measures provided by SAR OCT, the imaging system discerns native scattering differences between retinal layers and regions in healthy mice. In the second study, significant scattering angle shifts are observed in ischemic retinas. Finally, a cross-sectional study compares a transgenic murine model of AD (3xTg-AD) with age-matched wild type controls. By examining the distribution of scattering angles detected by the SAR-OCT system, significant differences are observed in the earliest ages of the diseased mice compared the control mice. In the final chapter, limitations of these studies as well as the imaging and image processing protocols are examined, and recommendations are made for future studies to leverage SAR-OCT for early detection of AD or other neurodegenerative diseases
Advisors/Committee Members: Rylander, H. Grady (Henry Grady), 1948- (advisor), Milner, Thomas E. (advisor), Dunn, Andrew K (committee member), Tunnell, James W (committee member), Vargas, Gracie (committee member).
Subjects/Keywords: Optical coherence tomography; Alzheimer's disease; Optical imaging; Retina
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APA (6th Edition):
-2308-0707. (2018). Scattering angle resolved optical coherence tomography for early retinal detection of Alzheimer’s disease in a murine model. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/10902
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-2308-0707. “Scattering angle resolved optical coherence tomography for early retinal detection of Alzheimer’s disease in a murine model.” 2018. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://dx.doi.org/10.26153/tsw/10902.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-2308-0707. “Scattering angle resolved optical coherence tomography for early retinal detection of Alzheimer’s disease in a murine model.” 2018. Web. 17 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-2308-0707. Scattering angle resolved optical coherence tomography for early retinal detection of Alzheimer’s disease in a murine model. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2018. [cited 2021 Jan 17].
Available from: http://dx.doi.org/10.26153/tsw/10902.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-2308-0707. Scattering angle resolved optical coherence tomography for early retinal detection of Alzheimer’s disease in a murine model. [Doctoral Dissertation]. University of Texas – Austin; 2018. Available from: http://dx.doi.org/10.26153/tsw/10902
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
16.
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
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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 17, 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. 17 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 17].
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
17.
-2993-9663.
Model observer for optimizing digital breast tomosynthesis for detection of multifocal and multicentric breast cancer.
Degree: PhD, Electrical and Computer Engineering, 2017, University of Texas – Austin
URL: http://dx.doi.org/10.26153/tsw/2453
► The goal of medical imaging is to acquire and display images of human anatomy and function such that they can be optimally interpreted by a…
(more)
▼ The goal of medical imaging is to acquire and display images of human anatomy and function such that they can be optimally interpreted by a trained observer, e.g., a radiologist. Start-of-art medical image quality is measured by the performance of an observer on a given clinical task. Since psychophysical studies are resource intensive, model observers are widely used as a surrogate in task-based assessment of image quality. Model observers are typically designed to detect at most one abnormality, e.g., a single lesion. However, in clinical practice, there may be multiple abnormalities in a single set of images, which can have a significant impact on treatment planning and outcomes. For example, patients with multifocal and multicentric breast cancer (MFMC), i.e., the presence of two or more tumor foci within the same breast, are more likely to undergo mastectomy rather than breast conservation therapy. Detecting multiple breast tumors is challenging because the prevalence of tumors varies significantly across breast regions, and radiologists do not know the number or location of tumors a priori. The vision of this dissertation is that digital breast tomosynthesis (DBT) has the potential to improve the detection of MFMC, and may offer advantages such as fewer false-positive findings, lower cost, and better accessibility. This dissertation focuses on the design and applications of a model observer to optimize DBT system geometries for detection of multiple breast tumors. This is significant and innovative because prior efforts to optimize DBT image quality only considered unifocal breast cancer scenarios. We highlight the following two main aspects of contributions in this dissertation: (1) We have developed a novel model observer that detects multiple abnormalities in anatomical backgrounds. (2) We have employed the extended 3D multi-lesion model observer to identify DBT system geometries that are most effective for the detection of MFMC. Our results demonstrate that the presence of more than one tumor present distinct challenges to DBT optimization, and that DBT geometries that yield images that are informative for the task of detecting unifocal breast cancer may not necessarily be informative for the task of detecting MFMC. We are validating the clinical relevance of our model observer studies with an ongoing human observer study with experienced breast imaging radiologists.
Advisors/Committee Members: Markey, Mia Kathleen (advisor), Park, Subok (committee member), Haygood, Tamara M. (committee member), Bovik, Alan C. (committee member), Ghosh, Joydeep (committee member), Tunnell, James W. (committee member).
Subjects/Keywords: Model observer; Medical image quality; Breast cancer; Breast imaging; Tomosynthesis; Multiple signal detection; Channelized Hotelling observer; Partial least squares
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APA (6th Edition):
-2993-9663. (2017). Model observer for optimizing digital breast tomosynthesis for detection of multifocal and multicentric breast cancer. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://dx.doi.org/10.26153/tsw/2453
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Chicago Manual of Style (16th Edition):
-2993-9663. “Model observer for optimizing digital breast tomosynthesis for detection of multifocal and multicentric breast cancer.” 2017. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://dx.doi.org/10.26153/tsw/2453.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
MLA Handbook (7th Edition):
-2993-9663. “Model observer for optimizing digital breast tomosynthesis for detection of multifocal and multicentric breast cancer.” 2017. Web. 17 Jan 2021.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Vancouver:
-2993-9663. Model observer for optimizing digital breast tomosynthesis for detection of multifocal and multicentric breast cancer. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2017. [cited 2021 Jan 17].
Available from: http://dx.doi.org/10.26153/tsw/2453.
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
Council of Science Editors:
-2993-9663. Model observer for optimizing digital breast tomosynthesis for detection of multifocal and multicentric breast cancer. [Doctoral Dissertation]. University of Texas – Austin; 2017. Available from: http://dx.doi.org/10.26153/tsw/2453
Note: this citation may be lacking information needed for this citation format:
Author name may be incomplete
University of Texas – Austin
18.
-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
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APA ·
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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 17, 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. 17 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 17].
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
University of Texas – Austin
19.
Wang, Bingqing.
Optical designs and image processing algorithms for optical coherence tomography detection of glaucoma.
Degree: PhD, Biomedical Engineering, 2014, University of Texas – Austin
URL: http://hdl.handle.net/2152/31289
► Optical Coherence Tomography (OCT) is an optical tomography technique which provides high resolution non-invasive three-dimensional (3D) structural images of the sample based on coherent properties…
(more)
▼ Optical Coherence Tomography (OCT) is an optical tomography technique which provides high resolution non-invasive three-dimensional (3D) structural images of the sample based on coherent properties of light. The dissertation focuses on the use of OCT systems for detecting glaucoma, which is the second leading cause of blindness worldwide. First, as a prerequisite of analyzing ophthalmologic OCT images, a retinal sublayer segmentation algorithm is presented and implemented with GPU assisted computation. Then, a polarization-sensitive optical coherence tomography (PS-OCT) system was constructed for the study of glaucoma. Three closely related clinical and animal studies on early-stage glaucoma detection using either OCT or PS-OCT were performed. Statistical analysis of the study results indicates that the scattering property of retinal nerve fiber layer (RNFL) is the earliest indicator for glaucoma. Finally, to investigate the scattering properties of RNFL, a pathlength-multiplexed scattering-angle-diverse optical coherence tomography (PM-SAD-OCT) system was designed and built. PM-SAD-OCT images were collected from human and rodent retina as well as earthworm nerve cord. PM-SAD-OCT system shows promising potentials to detect neurodegenerative diseases including glaucoma.
Advisors/Committee Members: Rylander, H. Grady (Henry Grady), 1948- (advisor), Milner, Thomas E. (advisor), Tunnell, James W. (committee member), Dunn, Andrew K. (committee member), Bovik, Alan C. (committee member).
Subjects/Keywords: Optical coherence tomography; Image processing
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APA (6th Edition):
Wang, B. (2014). Optical designs and image processing algorithms for optical coherence tomography detection of glaucoma. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/31289
Chicago Manual of Style (16th Edition):
Wang, Bingqing. “Optical designs and image processing algorithms for optical coherence tomography detection of glaucoma.” 2014. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/31289.
MLA Handbook (7th Edition):
Wang, Bingqing. “Optical designs and image processing algorithms for optical coherence tomography detection of glaucoma.” 2014. Web. 17 Jan 2021.
Vancouver:
Wang B. Optical designs and image processing algorithms for optical coherence tomography detection of glaucoma. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2014. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/31289.
Council of Science Editors:
Wang B. Optical designs and image processing algorithms for optical coherence tomography detection of glaucoma. [Doctoral Dissertation]. University of Texas – Austin; 2014. Available from: http://hdl.handle.net/2152/31289
20.
Pattani, Varun Paresh.
Understanding cell death response to gold nanoparticle-mediated photothermal therapy in 2D and 3D in vitro tumor models for improving cancer therapy.
Degree: PhD, Biomedical Engineering, 2013, University of Texas – Austin
URL: http://hdl.handle.net/2152/23106
► Gold nanoparticles, a class of plasmonic nanoparticle, have increasingly been explored as an imaging and therapeutic agent to treat cancer due to their characteristic surface…
(more)
▼ Gold nanoparticles, a class of plasmonic nanoparticle, have increasingly been explored as an imaging and therapeutic agent to treat cancer due to their characteristic surface plasmon resonance phenomenon and penchant for tumor accumulation. Photothermal therapy has been shown as a promising cancer treatment by delivering heat specifically to the tumor site via gold nanoparticles. In this study, we demonstrate that gold nanorod (GNR)-mediated photothermal therapy can be more effective through the understanding of cell death mechanisms. By targeting GNRs to various cellular localizations, we explored the association of GNR localization with cell death pathway response to photothermal therapy. Furthermore, we compared the 2D monolayer experiments with 3D in vitro tumor models, multicellular tumor spheroids (MCTS), to mimic the structure of in vivo tumors. With MCTS, we evaluated the cell death response with GNRs distributed only on the periphery, as seen in typical in vivo studies, and distributed evenly throughout the tumor.
We demonstrated that GNR localization influences the cell death response to photothermal therapy by showing the power threshold necessary to induce significant apoptotic and necrotic increases was lower for internalized GNRs than membrane-bound GNRs. Furthermore, apoptosis was found to increase with increasing laser power until the necrotic threshold and decreased above it, as necrosis became the dominant cell death pathway response. A similar trend was revealed with the 3D MCTS; however, the overall cell death percentages were lower, most likely due to the upregulated cell repair response and varied GNR distributions due to the presence of cell-cell and cell-matrix interactions. Furthermore, the uniformly distributed GNRs induced more apoptosis and necrosis than GNRs located in the MCTS periphery. In conclusion, we quantitatively analyzed the cell death pathway response to GNR-mediated photothermal therapy to establish that it has some dependence on GNR localization and distribution to gain a more thorough understanding of this response for photothermal therapy optimization.
Advisors/Committee Members: Tunnell, James W. (advisor).
Subjects/Keywords: Gold nanoparticle; Cancer therapy; Photothermal therapy; Cell death pathways; Two-photon microscopy; Flow cytometry
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APA (6th Edition):
Pattani, V. P. (2013). Understanding cell death response to gold nanoparticle-mediated photothermal therapy in 2D and 3D in vitro tumor models for improving cancer therapy. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/23106
Chicago Manual of Style (16th Edition):
Pattani, Varun Paresh. “Understanding cell death response to gold nanoparticle-mediated photothermal therapy in 2D and 3D in vitro tumor models for improving cancer therapy.” 2013. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/23106.
MLA Handbook (7th Edition):
Pattani, Varun Paresh. “Understanding cell death response to gold nanoparticle-mediated photothermal therapy in 2D and 3D in vitro tumor models for improving cancer therapy.” 2013. Web. 17 Jan 2021.
Vancouver:
Pattani VP. Understanding cell death response to gold nanoparticle-mediated photothermal therapy in 2D and 3D in vitro tumor models for improving cancer therapy. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2013. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/23106.
Council of Science Editors:
Pattani VP. Understanding cell death response to gold nanoparticle-mediated photothermal therapy in 2D and 3D in vitro tumor models for improving cancer therapy. [Doctoral Dissertation]. University of Texas – Austin; 2013. Available from: http://hdl.handle.net/2152/23106
21.
Lim, Liang.
Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis.
Degree: PhD, Biomedical Engineering, 2013, University of Texas – Austin
URL: http://hdl.handle.net/2152/23196
► The goal of this thesis is to study the potential of optical spectroscopy as a clinical diagnostic tool for melanoma and nonmelanoma skin cancer. Skin…
(more)
▼ The goal of this thesis is to study the potential of optical spectroscopy as a clinical diagnostic tool for melanoma and nonmelanoma skin cancer. Skin cancer is the most common cancer in the United States. Like most cancers, early diagnosis and treatment improves patient prognosis for both melanoma and nonmelanoma skin cancer. However, current “gold standard” for diagnosis is invasive, costly and time-consuming. A diagnostic procedure consists of a clinical examination of the suspicious lesion, followed by biopsy and histopathology, with an additional turnaround time of approximately one week. There is a need for an accurate, objective, noninvasive, and faster method to aid physician in diagnosing cancerous lesions, increasing diagnosis accuracy while preventing unnecessary biopsies. We propose Spectral Diagnosis, a system capable of noninvasive in vivo spectroscopic examination of human skin.
The research objectives are: (1) Probe pressure effects on in vivo spectroscopy measurements of human skin, (2) Clinical trial of Spectral Diagnosis, (3) Design, construction, and characterization of a confocal Raman microspectroscope. Spectral Diagnosis utilizes an optical fiber probe that transmits and collects optical spectra in contact with the suspected lesion. We identified short term and light probe pressure effects to be minimal on diagnostic parameters, and should not negatively influence diagnostic performance. We conducted a clinical trial at the
University of
Texas MD Anderson Cancer Center, and our results show that principal components from three spectroscopy modalities (diffuse reflectance spectroscopy, laser induced fluorescence spectroscopy, and Raman spectroscopy) provide excellent melanoma and nonmelanoma skin cancer diagnosis. We also constructed and characterized a Raman microspectroscope, with the goal of developing a physiological-based fitting model to better understand the analysis of in vivo Raman spectroscopy data from human skin tissue.
Advisors/Committee Members: Tunnell, James W. (advisor).
Subjects/Keywords: Spectroscopy; Skin cancer; Diagnosis; In vivo; Medical imaging
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APA (6th Edition):
Lim, L. (2013). Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/23196
Chicago Manual of Style (16th Edition):
Lim, Liang. “Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis.” 2013. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/23196.
MLA Handbook (7th Edition):
Lim, Liang. “Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis.” 2013. Web. 17 Jan 2021.
Vancouver:
Lim L. Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2013. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/23196.
Council of Science Editors:
Lim L. Clinical, non-invasive in vivo diagnosis of skin cancer using multimodal Spectral Diagnosis. [Doctoral Dissertation]. University of Texas – Austin; 2013. Available from: http://hdl.handle.net/2152/23196
22.
Bish, Sheldon Floyd.
Hyper-spectral diffuse reflectance spectroscopy imaging towards the identification of non-melanoma skin cancers.
Degree: PhD, Biomedical Engineering, 2013, University of Texas – Austin
URL: http://hdl.handle.net/2152/25141
► Non-melanoma skin cancer is the most prevalent malignancy in the world, with over a million annual positive diagnoses in the United States. If left untreated,…
(more)
▼ Non-melanoma skin cancer is the most prevalent malignancy in the world, with over a million annual positive diagnoses in the United States. If left untreated, these cancers cause morbidity and in rare cases, can become life threatening. The key to identifying and characterizing these tumors in the earliest stages, where they are most treatable lie in margin delineation in order to prevent recurrence. The visual obscurity of tumor morphology and physiology can make early detection a difficult task for dermatologists, particularly in the initial stages of cancer development. Tumor resection is a common course of action once they are discovered; however, there is a high recurrence rate due to incomplete removal of the malignant tissue. This dissertation presents an imaging system that can capture the spectral signatures correlating with morphological and physiological changes that accompany skin dysplasia. With this system, we may improve tumor margin delineation, reducing the number of incomplete tumor biopsies and false negative screenings. As an initial step of this process, we begin with a non-contact point sampling diffuse reflectance probe that mitigates the adverse effects of traditional contact probing. Validation of this probe is performed using tissue simulating phantoms spanning a biologically relevant range of optical and physiological properties to ensure that the non-contact format will not hinder performance relative to the contact probe. Cross polarization and auto-focus mechanisms were included in the design to reduce specular reflections and movement artifacts from in vivo measurements. This non-contact design was further developed into a platform for investigating the role of sampling geometry on diffuse reflectance measurements with the addition of a DMD spatial filter. Finally, we developed a hyperspectral DRSi system for the acquisition of wide-field maps of optical and physiological properties that is currently being tested on patients undergoing skin cancer screenings. The spectral output of this system has been validated for scattering and absorption across biologically relevant ranges using tissue simulating phantoms. The DRSi system was optimized for portability, ergonomics and resolution.
Advisors/Committee Members: Tunnell, James W. (advisor).
Subjects/Keywords: Spectroscopy; Optical imaging; Reflectance
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APA (6th Edition):
Bish, S. F. (2013). Hyper-spectral diffuse reflectance spectroscopy imaging towards the identification of non-melanoma skin cancers. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/25141
Chicago Manual of Style (16th Edition):
Bish, Sheldon Floyd. “Hyper-spectral diffuse reflectance spectroscopy imaging towards the identification of non-melanoma skin cancers.” 2013. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/25141.
MLA Handbook (7th Edition):
Bish, Sheldon Floyd. “Hyper-spectral diffuse reflectance spectroscopy imaging towards the identification of non-melanoma skin cancers.” 2013. Web. 17 Jan 2021.
Vancouver:
Bish SF. Hyper-spectral diffuse reflectance spectroscopy imaging towards the identification of non-melanoma skin cancers. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2013. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/25141.
Council of Science Editors:
Bish SF. Hyper-spectral diffuse reflectance spectroscopy imaging towards the identification of non-melanoma skin cancers. [Doctoral Dissertation]. University of Texas – Austin; 2013. Available from: http://hdl.handle.net/2152/25141
23.
Lim, Hyunji.
Temperature dependent refractive index of lipid tissue by optical coherence tomography imaging.
Degree: MSin Engineering, Biomedical Engineering, 2011, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2011-05-3694
► Temperature dependent optical properties of lipid tissue verify critical information of tissue dynamics which can be applied to tissue treatment and diagnosis of various pathological…
(more)
▼ Temperature dependent optical properties of lipid tissue verify critical information of tissue dynamics which can be applied to tissue treatment and diagnosis of various pathological features. Current methods of treating lipid rich tissues via heating are associated with post operation complications. Recent studies shows potential of lipid rich tissue removal by cooling. For monitoring cooling procedure and physical and chemical changes in lipid tissue, temperature dependent optical properties in subzero cooling need to be verified. This study designed heat transfer system estimating heat flux by cooling and programmed codes for image and data processing to obtain refractive indices of rodent subcutaneous lipid tissue. Phase transition of lipid tissue was observed and finally verified temperature dependent refractive index coefficient of lipid tissue from 24°C to -10°C.
Advisors/Committee Members: Milner, Thomas E. (advisor), Tunnell, James (committee member).
Subjects/Keywords: Optics; Lipid tissue; Adipose tissue; Lipolysis; Refractive index; Cooling
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APA (6th Edition):
Lim, H. (2011). Temperature dependent refractive index of lipid tissue by optical coherence tomography imaging. (Masters Thesis). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-05-3694
Chicago Manual of Style (16th Edition):
Lim, Hyunji. “Temperature dependent refractive index of lipid tissue by optical coherence tomography imaging.” 2011. Masters Thesis, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/ETD-UT-2011-05-3694.
MLA Handbook (7th Edition):
Lim, Hyunji. “Temperature dependent refractive index of lipid tissue by optical coherence tomography imaging.” 2011. Web. 17 Jan 2021.
Vancouver:
Lim H. Temperature dependent refractive index of lipid tissue by optical coherence tomography imaging. [Internet] [Masters thesis]. University of Texas – Austin; 2011. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-3694.
Council of Science Editors:
Lim H. Temperature dependent refractive index of lipid tissue by optical coherence tomography imaging. [Masters Thesis]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-3694
24.
Dana, Nicholas Pacheco.
Photoacoustic image guidance and tissue characterization in cardiovascular applications.
Degree: PhD, Biomedical engineering, 2016, University of Texas – Austin
URL: http://hdl.handle.net/2152/46211
► Collectively, cardiovascular diseases continue to be the leading cause of death, across nations and across decades. Improved diagnostic imaging methods offer promise to alleviate the…
(more)
▼ Collectively, cardiovascular diseases continue to be the leading cause of death, across nations and across decades. Improved diagnostic imaging methods offer promise to alleviate the morbidity associated with these diseases. Photoacoustic (PA) imaging is one such method, poised to make a significant impact on cardiovascular imaging, both as a research tool, as well as a clinical imaging modality. Offering the potential of molecular imaging in real-time, PA methods have been demonstrated in proof-of-concept studies tracking myocyte calcium dynamics. These results open the door to non-invasive longitudinal assessment of cardiac electrophysiological function, with implications for drug and contrast agent development. PA image guidance has also been extended to the characterization of cardiac radiofrequency ablation lesions. This method has been demonstrated to utilize endogenous chromophore changes resulting from ablation for the generation of depth-resolved tissue characterization maps, capable of assessing lesion extent. The technique has been subsequently validated by assessing high-intensity focused ultrasound ablation lesions in myocardium, with the hope for offering thermographic capabilities as well. While PA imaging offers such promise in cardiac ablation procedures, it is also in the process of clinical translation for image guidance and characterization in coronary artery disease applications. Research has shown, using Monte Carlo optical modeling, that using a simple dual-wavelength PA imaging technique has great potential for successful visualization of atherosclerotic plaques across multiple tissue types and at clinically relevant multiple millimeters of depth. Collectively these results offer a suite of PA imaging tools with the potential for molecular and thermographic imaging across a broad range of cardiovascular applications.
Advisors/Committee Members: Suggs, Laura J. (advisor), Emelianov, Stanislav Y. (advisor), Dunn, Andrew (committee member), Tunnell, James (committee member), Bouchard, Richard (committee member).
Subjects/Keywords: Photoacoustic; Cardiovascular; Imaging; Arrhythmia; Ablation; Atherosclerosis; Coronary; Monte Carlo
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APA (6th Edition):
Dana, N. P. (2016). Photoacoustic image guidance and tissue characterization in cardiovascular applications. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/46211
Chicago Manual of Style (16th Edition):
Dana, Nicholas Pacheco. “Photoacoustic image guidance and tissue characterization in cardiovascular applications.” 2016. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/46211.
MLA Handbook (7th Edition):
Dana, Nicholas Pacheco. “Photoacoustic image guidance and tissue characterization in cardiovascular applications.” 2016. Web. 17 Jan 2021.
Vancouver:
Dana NP. Photoacoustic image guidance and tissue characterization in cardiovascular applications. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2016. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/46211.
Council of Science Editors:
Dana NP. Photoacoustic image guidance and tissue characterization in cardiovascular applications. [Doctoral Dissertation]. University of Texas – Austin; 2016. Available from: http://hdl.handle.net/2152/46211
25.
Wang, Tianyi, 1982-.
Development and application of optical imaging techniques in diagnosing cardiovascular disease.
Degree: PhD, Biomedical Engineering, 2012, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2012-05-5215
► Atherosclerosis and specifically rupture of vulnerable plaques account for 23% of all deaths worldwide, far surpassing both infectious diseases and cancer. Plaque-based macrophages, often associated…
(more)
▼ Atherosclerosis and specifically rupture of vulnerable plaques account for 23% of all deaths worldwide, far surpassing both infectious diseases and cancer. Plaque-based macrophages, often associated with lipid deposits, contribute to atherogenesis from initiation through progression, plaque rupture and ultimately, thrombosis. Therefore, the macrophage is an important early cellular marker related to vulnerability of atherosclerotic plaques. The objective of my research is to assess the ability of multiple optical imaging modalities to detect, and further characterize the distribution of macrophages (having taken up plasmonic gold nanoparticles as a contrast agent) and lipid deposits in atherosclerotic plaques.
Tissue phantoms and macrophage cell cultures were used to investigate the capability of nanorose as an imaging contrast agent to target macrophages. Ex vivo aorta segments from a rabbit model of atherosclerosis after intravenous nanorose injection were imaged by optical coherence tomography (OCT), photothermal imaging (PTW) and two-photon luminescence microscopy (TPLM), respectively. OCT images depicted detailed surface structure of atherosclerotic plaques. PTW images identified nanorose-loaded macrophages (confirmed by co-registration of a TPLM image and corresponding RAM-11 stain on a histological section) associated with lipid deposits at multiple depths. TPLM images showed three-dimensional distribution of nanorose-loaded macrophages with a high spatial resolution. Imaging results suggest that superficial nanorose-loaded macrophages are distributed at shoulders on the upstream side of atherosclerotic plaques at the edges of lipid deposits. Combination of OCT with PTW or TPLM can simultaneously reveal plaque structure and composition, permitting assessment of plaque vulnerability during cardiovascular interventions.
Advisors/Committee Members: Milner, Thomas E. (advisor), Feldman, Marc (committee member), Johnston, Keith (committee member), Dunn, Andrew (committee member), Tunnell, James (committee member).
Subjects/Keywords: Cardiovascular disease; Macrophage; Lipid deposit; Nanorose; Optical coherence tomography; Photothermal imaging; Two-photon luminescence microscopy
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APA (6th Edition):
Wang, Tianyi, 1. (2012). Development and application of optical imaging techniques in diagnosing cardiovascular disease. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2012-05-5215
Chicago Manual of Style (16th Edition):
Wang, Tianyi, 1982-. “Development and application of optical imaging techniques in diagnosing cardiovascular disease.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/ETD-UT-2012-05-5215.
MLA Handbook (7th Edition):
Wang, Tianyi, 1982-. “Development and application of optical imaging techniques in diagnosing cardiovascular disease.” 2012. Web. 17 Jan 2021.
Vancouver:
Wang, Tianyi 1. Development and application of optical imaging techniques in diagnosing cardiovascular disease. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-5215.
Council of Science Editors:
Wang, Tianyi 1. Development and application of optical imaging techniques in diagnosing cardiovascular disease. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-5215
26.
Spivey, Eric Christopher.
Multiphoton lithography of mechanically and functionally tunable hydrogels.
Degree: PhD, Biomedical Engineering, 2012, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2012-05-5041
► As one of the few 3D microfabrication techniques available to researchers, multiphoton lithography (MPL) has generated considerable interest in the scientific community. By allowing researchers…
(more)
▼ As one of the few 3D microfabrication techniques available to researchers,
multiphoton lithography (MPL) has generated considerable interest in the scientific community. By allowing researchers to localize photochemistry to a femtoliter volume, MPL has permitted the fabrication of intricate, 3D microstructures from a range of materials, including protein hydrogels. MPL can be used to fabricate functional hydrogels on the scale of 100 μm, with features on the order of 1 μm. This dissertation examines existing MPL techniques to discover ways in which current processes can be modified to produce hydrogel products that are more useful for biomedical applications like tissue engineering. A new material is introduced that enables the fabrication of fully unconstrained hydrogel microstructures. In this context, A structure can be classified as “unconstrained” when it is free to translate and rotate without hindrance in three
dimensions, and is not attached to the substrate or any other structure. New processes are demonstrated that permit the fabrication of larger MPL hydrogels without sacrificing feature resolution. This allows the fabrication of millimeter-scale, high aspect ratio structures with features smaller than 10 μm. Methods are described for tuning and measuring the mechanical properties of MPL-fabricated hydrogels, and ways of tuning
the functional properties of the hydrogels are also examined.
Advisors/Committee Members: Shear, Jason B. (advisor), Schmidt, Christine E. (advisor), Dunn, Andrew (committee member), Roy, Krishnendu (committee member), Tunnell, James (committee member).
Subjects/Keywords: Multiphoton lithography; Microfabrication; Hydrogels
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APA (6th Edition):
Spivey, E. C. (2012). Multiphoton lithography of mechanically and functionally tunable hydrogels. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2012-05-5041
Chicago Manual of Style (16th Edition):
Spivey, Eric Christopher. “Multiphoton lithography of mechanically and functionally tunable hydrogels.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/ETD-UT-2012-05-5041.
MLA Handbook (7th Edition):
Spivey, Eric Christopher. “Multiphoton lithography of mechanically and functionally tunable hydrogels.” 2012. Web. 17 Jan 2021.
Vancouver:
Spivey EC. Multiphoton lithography of mechanically and functionally tunable hydrogels. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-5041.
Council of Science Editors:
Spivey EC. Multiphoton lithography of mechanically and functionally tunable hydrogels. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-5041
27.
-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
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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 17, 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. 17 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 17].
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
28.
Wang, Dan.
Real-time 3D visualization of organ deformations based on structured dictionary.
Degree: PhD, Electrical and Computer Engineering, 2012, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2012-05-4996
► Minimally invasive technique (MIS) revolutionized the field of surgery for its shorter hospitalization time, lower complication rates, and ultimately reduced morbidity and mortality. However, one…
(more)
▼ Minimally invasive technique (MIS) revolutionized the field of surgery for its shorter hospitalization
time, lower complication rates, and ultimately reduced morbidity and mortality.
However, one of the critical challenges that prevent it from reaching the full potentials is
the restricted visualization from the traditional monocular camera systems at the presence
of tissue deformations.
This dissertation aims to design a new approach which can provide the surgeons with
real time 3D visualization of complete organ deformations during the MIS operation. This
new approach even allows the surgeon to see through the wall of an organ rather than just
looking at its surface. The proposed design consists of two stages. The first training stage
identified the deformation subspaces from a training data set in the transformed spherical
harmonic domain, such that each surface can be sparsely represented in the structured
dictionary with low dimensionality. This novel idea is based on our experimental discovery
that the spherical harmonic coefficients of any organ surface lie in specific low dimensional
subspaces. The second reconstruction stage reconstructs the complete deformations in realtime
using surface samples obtained with an optical device from a limited field of view while
applying the structured dictionary.
The sparse surface representation algorithm is also applied to ultrasound image enhancement
and efficient surgical simulation. The former is achieved by fusing ultrasound samples
5
with optical data under proper weighting strategies. The high speed of surgical simulation
is obtained by decreasing the computational cost based on the high compactness of the
surface representation algorithm.
In order to verify the proposed approaches, we first use the computer models to demonstrate
that the proposed approach matches the accuracy of complex mathematical modeling
techniques. Then ex-vivo experiments are conducted on freshly excised porcine kidneys utilizing
a 3D MRI machine, a 3D optical device and an ultrasound machine to further test the feasibility under practical settings.
Advisors/Committee Members: Tewfik, Ahmed (advisor), Bovik, Alan (committee member), Caramanis, Constantine (committee member), Markey, Mia K. (committee member), Emelianov, Stanislav (committee member), Tunnell, James W. (committee member).
Subjects/Keywords: Organ deformation; Dictionary learning; Sparse representation
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APA ·
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APA (6th Edition):
Wang, D. (2012). Real-time 3D visualization of organ deformations based on structured dictionary. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2012-05-4996
Chicago Manual of Style (16th Edition):
Wang, Dan. “Real-time 3D visualization of organ deformations based on structured dictionary.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/ETD-UT-2012-05-4996.
MLA Handbook (7th Edition):
Wang, Dan. “Real-time 3D visualization of organ deformations based on structured dictionary.” 2012. Web. 17 Jan 2021.
Vancouver:
Wang D. Real-time 3D visualization of organ deformations based on structured dictionary. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-4996.
Council of Science Editors:
Wang D. Real-time 3D visualization of organ deformations based on structured dictionary. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-4996
29.
Liang, Jinyang, 1985-.
High-precision laser beam shaping and image projection.
Degree: PhD, Electrical and Computer Engineering, 2012, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2012-05-5053
► Laser beams with precisely controlled intensity profiles are essential for many areas. We developed a beam shaping system based on the digital micromirror device (DMD)…
(more)
▼ Laser beams with precisely controlled intensity profiles are essential for many areas. We developed a beam shaping system based on the digital micromirror device (DMD) for ultra-cold atom experiments and other potential applications. The binary DMD pattern was first designed by the error diffusion algorithm based on an accurate measurement of the quasi-Gaussian incident beam from a real-world laser. The DMD pattern was projected to the image plane by a bandwidth-limited 4f telescope that converted this pattern to the grayscale image.
The system bandwidth determined the theoretical limit of image precision by the digitization error. In addition, it controlled the spatial shape of the point spread function (PSF) that reflected the tradeoff between image precision and spatial resolution. PSF was used as a non-orthogonal basis set for iterative pattern refinement to seek the best possible system performance. This feedback process, along with stable performance of DMD, the blue-noise spectrum of the error diffusion algorithm, and low-pass filtering, guaranteed high-precision beam shaping performance.
This system was used to produce various beam profiles for different spatial frequency spectra. First, we demonstrated high-precision slowly-varying intensity beam profiles with an unprecedented high intensity accuracy. For flattop and linearly-tilted flattop beams, we achieved 0.20-0.34% root-mean-square (RMS) error over the entire measurement region. Second, two-dimensional sinusoidal-flattop beams were used to evaluate image precision versus system bandwidth. System evaluation confirmed that this system was capable of producing any spatial pattern with <3% RMS error for the most system bandwidth. This experiment extended the beam shaping to any system bandwidth and provided a reference to estimate the output image quality based on its spatial spectrum. Later experiment using a Lena-flattop beam profile demonstrated the arbitrary beam profile generation.
We implemented this system for applications on the homogenous optical lattice and dynamic optical trap generation. The DMD pattern was optimized by the iterative refinement process at the image feedback arm, and projected through a two-stage imaging system to form the desired beam profile at the working plane. Experiments demonstrated a high-precision beam shaping as well as a fast and dynamic control of the generated beam profile.
Advisors/Committee Members: Becker, Michael F. (advisor), Heinzen, Daniel J. (committee member), Tunnell, James W. (committee member), Evans, Brian L. (committee member), Bank, Seth R. (committee member).
Subjects/Keywords: Laser beam shaping; Spatial light modulator; Optical trap; Optical lattice
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APA (6th Edition):
Liang, Jinyang, 1. (2012). High-precision laser beam shaping and image projection. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2012-05-5053
Chicago Manual of Style (16th Edition):
Liang, Jinyang, 1985-. “High-precision laser beam shaping and image projection.” 2012. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/ETD-UT-2012-05-5053.
MLA Handbook (7th Edition):
Liang, Jinyang, 1985-. “High-precision laser beam shaping and image projection.” 2012. Web. 17 Jan 2021.
Vancouver:
Liang, Jinyang 1. High-precision laser beam shaping and image projection. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2012. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-5053.
Council of Science Editors:
Liang, Jinyang 1. High-precision laser beam shaping and image projection. [Doctoral Dissertation]. University of Texas – Austin; 2012. Available from: http://hdl.handle.net/2152/ETD-UT-2012-05-5053
30.
Hoy, Christopher Luk, 1982-.
Development of femtosecond laser endoscopic microsurgery.
Degree: PhD, Mechanical Engineering, 2011, University of Texas – Austin
URL: http://hdl.handle.net/2152/ETD-UT-2011-05-2659
► Femtosecond laser microsurgery has emerged as a remarkable technique for precise ablation of biological systems with minimal damage to their surrounding tissues. The combination of…
(more)
▼ Femtosecond laser microsurgery has emerged as a remarkable technique for precise ablation of biological systems with minimal damage to their surrounding tissues. The combination of this technique with nonlinear optical imaging provides a means of microscopic visualization to guide such surgery in situ. A clinical endoscope capable of image-guided femtosecond laser microsurgery will provide physicians a means for cellular-level microsurgery with the highest precision.
This dissertation focuses the development of a miniaturized fiber-coupled probe for image-guided microsurgery, towards future realization as a clinical endoscope. The first part of the dissertation describes the development of an 18-mm diameter probe. This development includes delivery of femtosecond laser pulses with pulse energy in excess of 1 µJ through air-core photonic bandgap fiber, laser beam scanning by a microelectromechanical system scanning mirror, and development of a new image reconstruction methodology for extracting increased temporal information during Lissajous beam scanning. During testing, the 18-mm probe compares favorably with the state-of-the-art as a microscopic imaging tool and we present the first known demonstration of cellular femtosecond laser microsurgery through an optical fiber.
The second part of the dissertation explores further refinement of the design into a streamlined package with 9.6 mm diameter and improved imaging resolution. Study of the optical performance through analytical and computer-aided optical design indicates that simple custom lenses can be designed that require only commercial-grade manufacturing tolerances while still producing a fully aberration-corrected microsurgical endoscope. With the 9.6-mm probe, we demonstrate nonlinear optical imaging, including tissue imaging of intrinsic signals from collagen, using average laser powers 2-3× lower than the current state-of-the-art. We also demonstrate the use of the 9.6-mm probe in conjunction with gold nanoparticles for enhanced imaging and microsurgery through plasmonics.
Finally, in the third part of this dissertation, we detail bench-top development of a new clinical application for combined femtosecond laser microsurgery and nonlinear optical imaging: the treatment of scarred vocal folds. We show the utility of femtosecond laser microsurgery for creating sub-epithelial voids in vocal fold tissue that can be useful for enhancing localization of injectable biomaterial treatments. We demonstrate that a single compact fiber laser system can be utilized for both microsurgery and imaging. Furthermore, the proposed clinical technique is shown to be achievable with parameters (e.g., pulse energy, focused spot size) that were found to be attainable with fiber-coupled probes while still achieving ablation speeds practical for clinical use.
Advisors/Committee Members: Ben-Yakar, Adela (advisor), Hall, Matthew J. (committee member), Ho, Paul S. (committee member), Sokolov, Konstantin V. (committee member), Tunnell, James W. (committee member).
Subjects/Keywords: Nonlinear optics; Laser ablation; Endoscopy; Laser surgery
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APA (6th Edition):
Hoy, Christopher Luk, 1. (2011). Development of femtosecond laser endoscopic microsurgery. (Doctoral Dissertation). University of Texas – Austin. Retrieved from http://hdl.handle.net/2152/ETD-UT-2011-05-2659
Chicago Manual of Style (16th Edition):
Hoy, Christopher Luk, 1982-. “Development of femtosecond laser endoscopic microsurgery.” 2011. Doctoral Dissertation, University of Texas – Austin. Accessed January 17, 2021.
http://hdl.handle.net/2152/ETD-UT-2011-05-2659.
MLA Handbook (7th Edition):
Hoy, Christopher Luk, 1982-. “Development of femtosecond laser endoscopic microsurgery.” 2011. Web. 17 Jan 2021.
Vancouver:
Hoy, Christopher Luk 1. Development of femtosecond laser endoscopic microsurgery. [Internet] [Doctoral dissertation]. University of Texas – Austin; 2011. [cited 2021 Jan 17].
Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-2659.
Council of Science Editors:
Hoy, Christopher Luk 1. Development of femtosecond laser endoscopic microsurgery. [Doctoral Dissertation]. University of Texas – Austin; 2011. Available from: http://hdl.handle.net/2152/ETD-UT-2011-05-2659
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Open Access Theses and Dissertations
