18 results on '"Jaedu Cho"'
Search Results
2. Combinatorial targeting of cancer bone metastasis using mRNA engineered stem cells
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Gultekin Gulsen, Chih Chun Yu, Jason L. Cheng, Robert L. Sah, Beatrice A. Tierra, Lizhi Sun, Leanne Hildebrand, Aude I. Segaliny, Michael J. Liao, Weian Zhao, Henry P. Farhoodi, Michael Toledano, Dongxu Liu, Jaedu Cho, Linan Liu, and Min-Ying Su
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0301 basic medicine ,Research paper ,Messenger ,mRNA engineering ,Regenerative Medicine ,Regenerative medicine ,Cell therapy ,Cytosine Deaminase ,Mice ,0302 clinical medicine ,2.1 Biological and endogenous factors ,Aetiology ,Cell Engineering ,Mesenchymal stem cell ,Cancer ,Tumor ,Membrane Glycoproteins ,Bone metastasis ,General Medicine ,3. Good health ,P-Selectin ,030220 oncology & carcinogenesis ,Public Health and Health Services ,Female ,Stem Cell Research - Nonembryonic - Non-Human ,Stem cell ,Development of treatments and therapeutic interventions ,Clinical Sciences ,Bone Neoplasms ,Breast Neoplasms ,Mesenchymal Stem Cell Transplantation ,General Biochemistry, Genetics and Molecular Biology ,Cell Line ,03 medical and health sciences ,Osteoprotegerin ,Cell Line, Tumor ,medicine ,Animals ,Humans ,RNA, Messenger ,Combination therapy ,Sialyl Lewis X Antigen ,5.2 Cellular and gene therapies ,business.industry ,Bone metastases ,Mesenchymal Stem Cells ,Genetic Therapy ,medicine.disease ,Stem Cell Research ,Xenograft Model Antitumor Assays ,030104 developmental biology ,RAW 264.7 Cells ,Cancer cell ,Cancer research ,RNA ,business ,Homing (hematopoietic) - Abstract
Background Bone metastases are common and devastating to cancer patients. Existing treatments do not specifically target the disease sites and are therefore ineffective and systemically toxic. Here we present a new strategy to treat bone metastasis by targeting both the cancer cells (“the seed”), and their surrounding niche (“the soil”), using stem cells engineered to home to the bone metastatic niche and to maximise local delivery of multiple therapeutic factors. Methods We used mesenchymal stem cells engineered using mRNA to simultaneously express P-selectin glycoprotein ligand-1 (PSGL-1)/Sialyl-Lewis X (SLEX) (homing factors), and modified versions of cytosine deaminase (CD) and osteoprotegerin (OPG) (therapeutic factors) to target and treat breast cancer bone metastases in two mouse models, a xenograft intratibial model and a syngeneic model of spontaneous bone metastasis. Findings We first confirmed that MSC engineered using mRNA produced functional proteins (PSGL-1/SLEX, CD and OPG) using various in vitro assays. We then demonstrated that mRNA-engineered MSC exhibit enhanced homing to the bone metastatic niche likely through interactions between PSGL-1/SLEX and P-selectin expressed on tumour vasculature. In both the xenograft intratibial model and syngeneic model of spontaneous bone metastasis, engineered MSC can effectively kill tumour cells and preserve bone integrity. The engineered MSC also exhibited minimal toxicity in vivo, compared to its non-targeted chemotherapy counterpart (5-fluorouracil). Interpretation Our combinatorial targeting of both the cancer cells and the niche represents a simple, safe and effective way to treat metastatic bone diseases, otherwise difficult to manage with existing strategies. It can also be applied to other cell types (e.g., T cells) and cargos (e.g., genome editing components) to treat a broad range of cancer and other complex diseases. Fund National Institutes of Health, National Cancer Institute of the National Institutes of Health, Department of Defense, California Institute of Regenerative Medicine, National Science Foundation, Baylx Inc., and Fondation ARC pour la recherche sur le cancer.
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- 2019
3. Effect of shot noise on simultaneous sensing in frequency division multiplexed diffuse optical tomographic imaging process
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Hansol Jang, Chang-Seok Kim, Keum-Shik Hong, Jaedu Cho, Gultekin Gulsen, and Gukbin Lim
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shot noise ,diffuse optical tomography ,time-division multiplexing ,frequency-division multiplexing ,lcsh:Chemical technology ,01 natural sciences ,Biochemistry ,Multiplexing ,Imaging phantom ,Article ,Analytical Chemistry ,Frequency-division multiplexing ,010309 optics ,Optics ,Time-division multiplexing ,0103 physical sciences ,lcsh:TP1-1185 ,0101 mathematics ,Electrical and Electronic Engineering ,Instrumentation ,Physics ,Tomographic reconstruction ,business.industry ,Shot noise ,Atomic and Molecular Physics, and Optics ,Diffuse optical imaging ,010101 applied mathematics ,Data set ,business - Abstract
© 2017 by the authors. Licensee MDPI, Basel, Switzerland. Diffuse optical tomography (DOT) has been studied for use in the detection of breast cancer, cerebral oxygenation, and cognitive brain signals. As optical imaging studies have increased significantly, acquiring imaging data in real time has become increasingly important. We have developed frequency-division multiplexing (FDM) DOT systems to analyze their performance with respect to acquisition time and imaging quality, in comparison with the conventional time-division multiplexing (TDM) DOT. A large tomographic area of a cylindrical phantom 60mmin diameter could be successfully reconstructed using both TDM DOT and FDM DOT systems. In our experiment with 6 source-detector (S-D) pairs, the TDM DOT and FDM DOT systems required 6.18 and 1 s, respectively, to obtain a single tomographic data set. While the absorption coefficient of the reconstruction image was underestimated in the case of the FDM DOT, we experimentally confirmed that the abnormal region can be clearly distinguished from the background phantom using both methods.
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- 2017
4. Breast density quantification using structured-light-based diffuse optical tomography simulations
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Min-Ying Su, Farouk Nouizi, Jaedu Cho, Jessica Ruiz, Gultekin Gulsen, Jeon-Hor Chen, Jie Zheng, and Yifan Li
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Materials science ,Physics::Medical Physics ,Iterative reconstruction ,01 natural sciences ,Synthetic data ,Article ,010309 optics ,03 medical and health sciences ,0302 clinical medicine ,Optics ,0103 physical sciences ,Humans ,Tomography, Optical ,Breast ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,Breast Density ,Stray light ,business.industry ,Phantoms, Imaging ,Inverse problem ,Magnetic Resonance Imaging ,Atomic and Molecular Physics, and Optics ,Diffuse optical imaging ,Wavelength ,030220 oncology & carcinogenesis ,Feasibility Studies ,Female ,Tomography ,business ,Algorithms ,Structured light - Abstract
We present the feasibility of structured-light-based diffuse optical tomography (DOT) to quantify the breast density with an extensive simulation study. This study is performed on multiple numerical breast phantoms built from magnetic resonance imaging (MRI) images. These phantoms represent realistic tissue morphologies and are given typical breast optical properties. First, synthetic data are simulated at five wavelengths using our structured-light-based DOT forward problem. Afterwards, the inverse problem is solved to obtain the absorption images and subsequently the chromophore concentration maps. Parameters, such as segmented volumes and mean concentrations, are extracted from these maps and used in a regression model to estimate the percent breast densities. These estimations are correlated with the true values from MRI, r = 0.97, showing that our new technique is promising in measuring breast density.
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- 2017
5. Feasibility study of high spatial resolution multimodality fluorescence tomography in ex vivo biological tissue
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Tiffany C. Kwong, Jaedu Cho, Farouk Nouizi, Uma Sampathkumaran, Yuting Lin, and Gultekin Gulsen
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Indocyanine Green ,Materials science ,Image Processing ,Bioengineering ,02 engineering and technology ,Optical Physics ,01 natural sciences ,Phantoms ,Article ,Fluorescence ,Imaging ,Pectoralis Muscles ,010309 optics ,Optics ,Computer-Assisted ,In vivo ,0103 physical sciences ,Breast Cancer ,Image Processing, Computer-Assisted ,Animals ,Tomography, Optical ,Electrical and Electronic Engineering ,Coloring Agents ,Engineering (miscellaneous) ,Image resolution ,Tomography ,Fluorescence tomography ,Cancer ,business.industry ,Phantoms, Imaging ,Mechanical Engineering ,Resolution (electron density) ,Reconstruction algorithm ,021001 nanoscience & nanotechnology ,Atomic and Molecular Physics, and Optics ,Diffuse optical imaging ,Feasibility Studies ,0210 nano-technology ,business ,Chickens ,Ex vivo ,Optical ,Algorithms - Abstract
Previously, we demonstrated that temperature-modulated fluorescence tomography (TM-FT) could provide fluorescence images with high quantitative accuracy and the spatial resolution of focused ultrasound. TM-FT is based on scanning the focused ultrasound across the medium to activate temperature-reversible fluorescent nanoprobes (ThermoDots). This technique can resolve small fluorescent targets located several centimeters deep in turbid media with millimeter resolution. Our past studies with this multimodality technique used agar phantoms, which could not represent the true heterogeneous nature of the acoustic and optical properties of biological tissue. In this work, we report the results of the first TM-FT study performed on ex vivo chicken breast tissue. In order to improve the spatial resolution of this technique, diffuse optical tomography is also used to better estimate the optical property maps of the tissue, which is utilized as functional a priori for the TM-FT reconstruction algorithm. These ex vivo results show that TM-FT can accurately recover the concentration and position of a 1.5 mm×5 mm inclusion filled with ThermoDots. Since the inclusion is embedded 2cm deep in the chicken breast sample, these results demonstrate the great potential of TM-FT for future in vivo small animal imaging.
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- 2017
6. Multispectral fluorescence diffuse optical tomography
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Jaedu Cho, Pei An Lo, Farouk Nouizi, Gultekin Gulsen, and Huihua Kenny Chiang
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0301 basic medicine ,Materials science ,business.industry ,Multispectral image ,Reconstruction algorithm ,Laser ,Fluorescence ,Imaging phantom ,Diffuse optical imaging ,law.invention ,03 medical and health sciences ,Wavelength ,chemistry.chemical_compound ,030104 developmental biology ,Optics ,chemistry ,law ,business ,Indocyanine green - Abstract
Fluorescence diffuse optical tomography (FDOT) has been widely used for in vivo small animal studies and the illposed problem in reconstruction can be eased by utilizing structural a priori obtained from an anatomic imaging modality. In this study, a multispectral fluorescence tomography (FT) is used, which has shown the ability to detect subtle shifts in the ICG absorption spectrum in our previous study. The imaging system is in trans-illumination mode with a swept-wavelength laser and a CCD on a rotation gantry and the structural image from the X-ray computed tomography is used to guide and constrain the FT reconstruction algorithm. In this work, a phantom with two inclusions filled with different fluorophores is utilized to evaluate whether the spectral information obtained using sweptwavelength laser can distinguish these two inclusions. The images are captured from 8 different views with three different wavelengths.
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- 2017
7. Multi-wavelength fluorescence tomography
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Tiffany C. Kwong, Pei An Lo, Farouk Nouizi, Jaedu Cho, Gultekin Gulsen, Huihua Kenny Chiang, and Chang-Seok Kim
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Fluorophore ,Materials science ,Scattering ,business.industry ,Multispectral image ,Near-infrared spectroscopy ,01 natural sciences ,Fluorescence ,Diffuse optical imaging ,030218 nuclear medicine & medical imaging ,010309 optics ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Optics ,chemistry ,0103 physical sciences ,Optoelectronics ,Tomography ,Absorption (electromagnetic radiation) ,business - Abstract
The strong scattering and absorption of light in biological tissue makes it challenging to model the propagation of light, especially in deep tissue. This is especially true in fluorescent tomography, which aims to recover the internal fluorescence source distribution from the measured light intensities on the surface of the tissue. The inherently ill-posed and underdetermined nature of the inverse problem along with strong tissue scattering makes Fluorescence Tomography (FT) extremely challenging. Previously, multispectral detection fluorescent tomography (FT) has been shown to improve the image quality of FT by incorporating the spectral filtering of biological tissue to provide depth information to overcome the inherent absorption and scattering limitations. We investigate whether multi-wavelength fluorescent tomography can be used to distinguish the signals from multiple fluorophores with overlapping fluorescence spectrums using a unique near-infrared (NIR) swept laser. In this work, a small feasibility study was performed to see whether multi-wavelength FT can be used to detect subtle shifts in the absorption spectrum due to differences in fluorophore microenvironment.
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- 2016
8. Diffuse optical tomography with structured-light patterns to quantify breast density
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Yifan Li, Farouk Nouizi, Gultekin Gulsen, Jie Zheng, Jeon-Hor Chen, Jessica Kwong, Min-Ying Su, and Jaedu Cho
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medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Cancer ,Magnetic resonance imaging ,medicine.disease ,01 natural sciences ,Diffuse optical imaging ,010309 optics ,03 medical and health sciences ,0302 clinical medicine ,Breast cancer ,030220 oncology & carcinogenesis ,0103 physical sciences ,medicine ,Mammography ,Medical physics ,Radiology ,Breast density ,Risk factor ,skin and connective tissue diseases ,business ,Structured light - Abstract
Breast density is an independent risk factor for breast cancer, where women with denser breasts are more likely to develop cancer. By identifying women at higher risk, healthcare providers can suggest screening at a younger age to effectively diagnose and treat breast cancer in its earlier stages. Clinical risk assessment models currently do not incorporate breast density, despite its strong correlation with breast cancer. Current methods to measure breast density rely on mammography and MRI, both of which may be difficult to use as a routine risk assessment tool. We propose to use diffuse optical tomography with structured-light to measure the dense, fibroglandular (FGT) tissue volume, which has a different chromophore signature than the surrounding adipose tissue. To test the ability of this technique, we performed simulations by creating numerical breast phantoms from segmented breast MR images. We looked at two different cases, one with a centralized FGT distribution and one with a dispersed distribution. As expected, the water and lipid volumes segmented at half-maximum were overestimated for the dispersed case. However, it was noticed that the recovered water and lipid concentrations were lower and higher, respectively, than the centralized case. This information may provide insight into the morphological distribution of the FGT and can be a correction in estimating the breast density.
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- 2016
9. Fourier Domain Optical Coherence Tomography for Retinal Imaging with 800-nm Swept Source: Real-time Resampling in k-domain
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Hyun-Woo Song, Jaedu Cho, Chang-Seok Kim, Moon-Youn Jung, Seunghwan Kim, Sang-Won Lee, and Bong-Kyu Kim
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Point spread function ,Optical amplifier ,Materials science ,medicine.diagnostic_test ,business.industry ,Filter (signal processing) ,Laser ,Atomic and Molecular Physics, and Optics ,law.invention ,Wavelength ,Optics ,Optical coherence tomography ,law ,medicine ,Wavenumber ,business ,Sensitivity (electronics) - Abstract
In this study, we demonstrated Fourier-domain/swept-source optical coherence tomography (FD/SS-OCT) at a center wavelength of 800 nm for in vivo human retinal imaging. A wavelength-swept source was constructed with a semiconductor optical amplifier, a fiber Fabry-Perot tunable filter, isolators, and a fiber coupler in a ring cavity. Our swept source produced a laser output with a tuning range of 42 nm (779 to 821 nm) and an average power of 3.9 mW. The wavelength-swept speed in this configuration with bidirectionality is 2,000 axial scans per second. In addition, we suggested a modified zero-crossing method to achieve equal sample spacing in the wavenumber (k) domain and to increase the image depth range. FD/SS-OCT has a sensitivity of ~89.7 dB and an axial resolution of 10.4 μm in air. When a retinal image with 2,000 A-lines/frame is obtained, an acquisition speed of 2.0 fps is achieved.
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- 2011
10. High resolution 3D fluorescence tomography using ballistic photons
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Jaedu Cho, Farouk Nouizi, Jie Zheng, Gultekin Gulsen, and Jessica Kwong
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Physics ,Photon ,business.industry ,Multiphysics ,Detector ,Laser ,Photon counting ,law.invention ,Optics ,law ,Calibration ,Ballistic photon ,business ,Image resolution - Abstract
We are developing a ballistic-photon based approach for improving the spatial resolution of fluorescence tomography using time-domain measurements. This approach uses early photon information contained in measured time-of-fight distributions originating from fluorescence emission. The time point spread functions (TPSF) from both excitation light and emission light are acquired with gated single photon Avalanche detector (SPAD) and time-correlated single photon counting after a short laser pulse. To determine the ballistic photons for reconstruction, the lifetime of the fluorophore and the time gate from the excitation profiles will be used for calibration, and then the time gate of the fluorescence profile can be defined by a simple time convolution. By mimicking first generation CT data acquisition, the sourcedetector pair will translate across and also rotate around the subject. The measurement from each source-detector position will be reshaped into a histogram that can be used by a simple back-projection algorithm in order to reconstruct high resolution fluorescence images. Finally, from these 2D sectioning slides, a 3D inclusion can be reconstructed accurately. To validate the approach, simulation of light transport is performed for biological tissue-like media with embedded fluorescent inclusion by solving the diffusion equation with Finite Element Method using COMSOL Multiphysics simulation. The reconstruction results from simulation studies have confirmed that this approach drastically improves the spatial resolution of fluorescence tomography. Moreover, all the results have shown the feasibility of this technique for high resolution small animal imaging up to several centimeters.
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- 2015
11. Excitation light leakage suppression using temperature sensitive fluorescent agents
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Yu-Wen Chan, Jaedu Cho, Jessica Kwong, Tiffany C. Kwong, Yue Zhu, Maksudul M. Alam, Gultekin Gulsen, Farouk Nouizi, and Uma Sampathkumaran
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Fluorescence-lifetime imaging microscopy ,Optics ,Materials science ,Two-photon excitation microscopy ,business.industry ,Optoelectronics ,Fluorescence correlation spectroscopy ,business ,Laser-induced fluorescence ,Fluorescence ,Fluorescence spectroscopy ,Excitation ,Leakage (electronics) - Abstract
Fluorescence tomography is a non invasive, non ionizing imaging technique able to provide a 3D distribution of fluorescent agents within thick highly scattering mediums, using low cost instrumentation. However, its low spatial resolution due to undetermined and ill-posed nature of its inverse problem has delayed its integration into the clinical settings. In addition, the quality of the fluorescence tomography images is degraded due to the excitation light leakage contaminating the fluorescence measurements. This excitation light leakage results from the excitation photons that cannot be blocked by the fluorescence filters. In this contribution, we present a new method to remove this excitation light leakage noise based on the use of a temperature sensitive fluorescence agents. By performing different sets of measurements using this temperature sensitive agents at multiple temperatures, the excitation light leakage can be estimated and then removed from the measured fluorescence signals . The results obtained using this technique demonstrate its potential for use in in-vivo small animal imaging.
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- 2015
12. Diffuse optical imaging of the breast using structured-light
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Jie Zheng, Jeon-Hor Chen, Jaedu Cho, Farouk Nouizi, Yifan Li, Min-Ying Su, Gultekin Gulsen, and Jessica Kwong
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medicine.diagnostic_test ,business.industry ,Computer science ,Near-infrared spectroscopy ,Reconstruction algorithm ,medicine.disease ,Imaging phantom ,Diffuse optical imaging ,Functional imaging ,Breast cancer screening ,Optics ,Breast cancer ,medicine ,Spectroscopy ,business ,Photon diffusion ,Image restoration ,Structured light - Abstract
Diffuse optical imaging with structured-light illumination and detection can provide rapid, wide-field anatomical and functional imaging of the breast with an application for breast cancer screening. Our aims for this study were to test the feasibility of structured-light, test our pattern set, and develop and optimize our image reconstruction algorithm. For our phantom studies, we created an agar phantom with dimensions similar to a compressed breast. A cubic inclusion of 30mm by 30mm by 25mm with twice the amount of absorption contrast than the background was placed at the center. Near-infrared light of eleven patterns including a full illumination and single stripes was illuminated onto the breast phantom and detected with a CCD camera, with integration of the signals according to the patterns performed post-data acquisition, with a total of 121 measurements. These measurements were then used in our reconstruction algorithm that iteratively minimized the difference between the collected data and the estimation from our FEM-based forward model of photon diffusion to calculate the absorption values. Reconstructions of the 3D absorption maps detect an inclusion at the center and indicate that our selected set of patterns may be sufficient for structured-light imaging. We are currently improving our instrumentation and testing with additional phantom studies, while also performing simulations of numerical breast phantoms created from MR images to test structured-light’s ability to image complex and realistic breast tissue composition. We hope to use this technique as optical method to image molecular markers, such as hemoglobin, water and lipid, within the breast.
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- 2015
13. A fiber Bragg grating sensor interrogation system based on a linearly wavelength-swept thermo-optic laser chip
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Hwi Don Lee, Myung Yung Jeong, Jaedu Cho, Hyung Seok Lee, Chang-Seok Kim, and Hyo Jin Kim
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Materials science ,strain sensor ,thermo-optic effect ,lcsh:Chemical technology ,Biochemistry ,Signal ,Article ,Analytical Chemistry ,law.invention ,fiber Bragg grating ,Optics ,Fiber Bragg grating ,law ,Electronic engineering ,lcsh:TP1-1185 ,Electrical and Electronic Engineering ,Interrogation ,Instrumentation ,Range (particle radiation) ,business.industry ,swept source ,Chip ,Laser ,Atomic and Molecular Physics, and Optics ,Wavelength ,Reflection (physics) ,business - Abstract
A linearized wavelength-swept thermo-optic laser chip was applied to demonstrate a fiber Bragg grating (FBG) sensor interrogation system. A broad tuning range of 11.8 nm was periodically obtained from the laser chip for a sweep rate of 16 Hz. To measure the linear time response of the reflection signal from the FBG sensor, a programmed driving signal was directly applied to the wavelength-swept laser chip. The linear wavelength response of the applied strain was clearly extracted with an R-squared value of 0.99994. To test the feasibility of the system for dynamic measurements, the dynamic strain was successfully interrogated with a repetition rate of 0.2 Hz by using this FBG sensor interrogation system.
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- 2014
14. Development of a spectrally resolved fluorescence tomography system using a NIR swept laser and a digital micromirror array based detection system
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Jaedu Cho, Orhan Nalcioglu, Jie Zheng, Gultekin Gulsen, Chang-Seok Kim, and Seung Woan Jeon
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Materials science ,business.industry ,Near-infrared spectroscopy ,Multispectral image ,Laser ,law.invention ,Digital micromirror device ,Wavelength ,chemistry.chemical_compound ,Optics ,chemistry ,law ,Optoelectronics ,Spectral resolution ,Absorption (electromagnetic radiation) ,business ,Indocyanine green - Abstract
We developed a spectrally-resolved fluorescence tomography (FT) system using a new source and detection unit. On the source side, we utilized a near-infrared (NIR) swept laser-based technology and on the detection side, we developed a digital micromirror device (DMD) based spectrally-resolved detection unit. We demonstrated the development of a NIR swept laser centered at 800 nm for FT, which covers the maximum absorption wavelength of a NIR fluorescence dye, indo-cyanine green (ICG) in plasma. Two different ICG samples whose absorption characteristics were slightly different were used to demonstrate the performance of the NIR swept laser-based FT system, and this FT system was able to show the difference of absorption between the ICG samples. In addition, we also developed a prototype spectrally-resolved detection unit based on the DMD. This detection system provided a spectral resolution of 15 nm and the possibility of simultaneous detection of multiple fluorescence spectra.
- Published
- 2014
15. Diffuse optical tomography using wavelength-swept laser
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Orhan Nalcioglu, Gultekin Gulsen, Myung Yung Jeong, Gukbin Lim, Chang-Seok Kim, and Jaedu Cho
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Physics ,Distributed feedback laser ,medicine.diagnostic_test ,business.industry ,Far-infrared laser ,Physics::Optics ,Optical modulation amplitude ,Laser ,Diffuse optical imaging ,law.invention ,Optics ,law ,medicine ,Optoelectronics ,Laser power scaling ,Optical tomography ,business ,Tunable laser - Abstract
The design and implementation of a diffuse optical tomography system using wavelength-swept laser is described. Rapid and continuous wavelength change is utilized for high speed spectral scanning from 775 nm to 875 nm optical wavelength. Maximum speed of wavelength repetition is 1 kHz and averaged output power of the wavelength-swept laser is 20 mW. A fiber-optic Sagnac interferometer is incorporated to conduct passive amplitude modulation of the wavelength-swept laser. It is shown that the wavelength-swept laser can be successfully incorporated to the DOT system, and then reduces wavelength-shifting time and hardware complexity in multi-wavelength DOT implementation.
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- 2013
16. Implementation of a new scanning method for high-resolution fluorescence tomography using thermo-sensitive fluorescent agents
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Tiffany C. Kwong, Farouk Nouizi, Uma Sampathkumaran, Yuting Lin, Jaedu Cho, and Gultekin Gulsen
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Hot Temperature ,Materials science ,Fluorophore ,Contrast Media ,High resolution ,Bioengineering ,Optical Physics ,Sensitivity and Specificity ,Article ,Fluorescence ,Phantoms ,Imaging ,High-Energy Shock Waves ,Sonication ,chemistry.chemical_compound ,Optics ,Data acquisition ,High spatial resolution ,Tomography, Optical ,Electrical and Electronic Engineering ,Tomography ,Image resolution ,Fluorescent Dyes ,Fluorescence tomography ,Microscopy ,Quantum Physics ,Phantoms, Imaging ,business.industry ,Scattering ,Temperature ,Reproducibility of Results ,Equipment Design ,Image Enhancement ,Atomic and Molecular Physics, and Optics ,Equipment Failure Analysis ,Microscopy, Fluorescence ,chemistry ,Biomedical Imaging ,business ,Optical - Abstract
Conventional fluorescence tomography provides images of the distribution of fluorescent agents within highly scattering media, but suffers from poor spatial resolution. Previously, we introduced a new method termed “temperature-modulated fluorescence tomography” (TM-FT) that generates fluorescence images with high spatial resolution. TM-FT first uses focused ultrasound to locate the distribution of temperature-sensitive fluorescence probes. Afterward, this a priori information is utilized to improve the performance of the inverse solver for conventional fluorescence tomography and reveal quantitatively accurate fluorophore concentration maps. However, the disadvantage of this novel method is the long data acquisition time as the ultrasound beam was scanned in a step-and-shoot mode. In this Letter, we present a new, fast scanning method that reduces the imaging time 40 fold. By continuously scanning the ultrasound beam over a 50 mm by 25 mm field-of-view, high-resolution fluorescence images are obtained in less than 29 min, which is critical for in vivo small animal imaging.
- Published
- 2015
17. 800-nm-centered swept laser for spectroscopic optical coherence tomography
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Jaedu Cho, Chang-Seok Kim, and Gultekin Gulsen
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Isosbestic point ,Materials science ,medicine.diagnostic_test ,Absorption spectroscopy ,business.industry ,Attenuation ,Lateral resolution ,Condensed Matter Physics ,Laser ,Industrial and Manufacturing Engineering ,Atomic and Molecular Physics, and Optics ,law.invention ,Optics ,Optical coherence tomography ,law ,medicine ,business ,Instrumentation - Abstract
The isosbestic point of oxy- and deoxy-hemoglobin at 800 nm is an important point in biomedical optical spectroscopic imaging. We have developed a novel swept laser centered at 800 nm and demonstrated its performance for spectroscopic optical coherence tomography. The measured −10 dB spectral bandwidth of the swept laser was 40 nm and averaged laser output power per sweep was 4 mW. This swept laser was incorporated into our OCT system and used to measure non-scattering liquid phantoms and blood samples. The measured maximum sensitivity and roll-off rate over a range of image depths were 112 dB and − 1.45 dB mm−1, respectively. The minimum axial resolution of the OCT system was 8.06 μm at a depth of 2.4 mm. Quantitative and localized absorption spectra were recovered from the non-scattering liquid phantoms. In addition, the measured localized wavelength-dependent attenuation difference of oxygenated and deoxygenated blood was 4.6-fold.
- Published
- 2014
18. Three-dimensional surface phase imaging based on integrated thermo-optic swept laser
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Min-Cheol Oh, Jaedu Cho, Young-Ouk Noh, Chang-Seok Kim, Hyo Jin Kim, and Zhongping Chen
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Materials science ,business.industry ,Applied Mathematics ,Resolution (electron density) ,Phase (waves) ,Laser ,Signal ,Waveguide (optics) ,law.invention ,Wavelength ,Optics ,law ,Phase imaging ,Surface geometry ,business ,Instrumentation ,Engineering (miscellaneous) - Abstract
We developed an optical frequency domain imaging (OFDI) system based on an integrated thermo-optic swept laser to achieve three-dimensional surface imaging. The wavelength was swept by applying a heating signal to a thermo-optic polymeric waveguide. The sub-micrometer surface profile was converted from the three-dimensional phase information of the OFDI system on various samples used as resolution targets with a step height of 120 nm.
- Published
- 2014
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