1. Articles from Jaeyul Lee

    1-17 of 17
    1. Identification of Organs Inside Hard Tick Body Using Spectral-domain Optical Coherence Tomography

      Identification of Organs Inside Hard Tick Body Using Spectral-domain Optical Coherence Tomography

      Ixodidae tick, also known as a hard tick, is one of the major vectors of various tick-borne diseases. Studying its anatomy is the fundamental approach for diverse acarological studies and the key to understanding tick morphology. However, the conventional methods of observing internal organs rely primarily on dissection, which damages specimens irrecoverably. In this study, we developed an optical coherence tomography (OCT) system to non-invasively investigate the morphological characteristics of the hard tick. Herein, OCT imaging was conducted by the developed spectral-domain OCT (SD-OCT) system with two different objective lenses. The developed system provides an axial resolution (in the air ...

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    2. Vision-Inspection-Synchronized Dual Optical Coherence Tomography for High-Resolution Real-Time Multidimensional Defect Tracking in Optical Thin Film Industry

      Vision-Inspection-Synchronized Dual Optical Coherence Tomography for High-Resolution Real-Time Multidimensional Defect Tracking in Optical Thin Film Industry

      Large-scale product inspection is an important aspect in thin film industry to identify defects with a high precision. Although vision line scan camera (VLSC)-based inspection has been frequently implemented, it is limited to surface inspections. Therefore, to overcome the conventional drawbacks, there is a need to extend inspection capabilities to internal structures. Considering that VLSC systems have access to rich information, such as color and texture, high-resolution real-time multimodal optical synchronization between VLSC and dual spectral domain optical coherence tomography (SD-OCT) systems was developed with a laboratory customized in-built automated defect-tracking algorithm for optical thin films (OTFs). Distinguishable differences ...

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    3. Intra-operative Optical Coherence Imaging of In-vivo Chronic Otitis Media followed by Post-operative Audiogram Assessments

      Intra-operative Optical Coherence Imaging of In-vivo Chronic Otitis Media followed by Post-operative Audiogram Assessments

      The successful surgery of chronic otitis media (COM) is challenging; this depends on the surgeon's knowledge of the optical visibility of surgical microscopes. Herein, we reported the utilization of intra-surgical optical coherence tomography (OCT) system to effectively guide the surgery of COM based on augmented reality with cross-sectional images. The intra-surgical spectral-domain OCT system with a center wavelength of 846 nm was capable of obtaining non-invasive, high-resolution, and high-speed visualizations with an axial resolution of 8 μm, lateral resolution of 30 μm, and an extended working distance of 280 mm. Three patients with COM were involved in this research ...

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    4. Fabrication of Dental Crown by Optical Coherence Tomography: A Pilot Study

      Fabrication of Dental Crown by Optical Coherence Tomography: A Pilot Study

      Digital impressions have been studied for better gingival retraction in including the under subgingival finish line condition. Here, we employed swept-source optical coherence tomography (SS-OCT) of 1310 nm wavelength, which is capable of noninvasive, high-resolution, and high-speed, to discern the utilization-possibility for supporting the fabrication of the dental crown. A three-dimensional (3D) abutment was used at the 0.5 mm of the subgingival finish line below the level of the gingiva. The SS-OCT system scanned a field of view of 10 mm × 10 mm using the 3D working model by the depth-directional three focal points. The obtained 1500 images of ...

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    5. Non-invasive optical screening of Streptococcus Pneumonia based inflammatory changes of the tympanic membrane and mastoid mucosa in guinea pig otitis media using optical coherence tomography

      Non-invasive optical screening of Streptococcus Pneumonia based inflammatory changes of the tympanic membrane and mastoid mucosa in guinea pig otitis media using optical coherence tomography

      Abstract: The accurate screening of otitis media (OM) lies in clarifying the numerous confounding and quantitative factors that are discovered during primary inspections. Increased awareness about bacterial biofilms and inflammation has allowed researchers to develop a better understanding of the bacterial infections that occur in the middle ear. In this study, four live guinea pigs were inoculated with Streptococcus pneumonia to induce OM-related inflammatory changes. Since optical techniques have been effectively used for diagnosis in medicine, low-coherence interferometry-based optical coherence tomography (OCT) was employed for depth-resolved high-resolution data screening. Multiple locations of the tympanic membrane (TM), mastoid mucosa, and round ...

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    6. Assessment of the Inner Surface Roughness of 3D Printed Dental Crowns via Optical Coherence Tomography Using a Roughness Quantification Algorithm

      Assessment of the Inner Surface Roughness of 3D Printed Dental Crowns via Optical Coherence Tomography Using a Roughness Quantification Algorithm

      Abstract: Dental crowns are used to restore decayed or chipped teeth, where their surfaces play a key role in this restoration process, as they affect the fitting and stable bonding of the prostheses. The surface texture of crowns can interfere with this restoration process, therefore the measurement of their inner surface roughness is very important but difficult to achieve using conventional imaging methods. In this study, the inner surfaces of dental crowns were three-dimensionally (3D) visualized using swept-source optical coherence tomography (SS-OCT) system. Nine crowns were fabricated with a commercial 3D printer using three different hatching methods (one-way, cross, and ...

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    7. Dynamic compensation of path length difference in optical coherence tomography by an automatic temperature control system of optical fiber

      Dynamic compensation of path length difference in optical coherence tomography by an automatic temperature control system of optical fiber

      Optical fiber is widely used in optical coherence tomography (OCT) to propagate light precisely with low attenuation and low dispersion. However, the total optical path length within the optical fiber varies in accordance with changes of the temperature. This leads changes in the total optical travel path of the interfering signals and results in shifting of OCT image position to an unintended depth pixel value. In this paper, we presented the temperature-based automatic path length compensating method in OCT to limit the external temperature effect and control the image position in micro-scale without manual movement of optical components. By utilizing ...

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    8. Optical Interferometric Fringe Pattern-Incorporated Spectrum Calibration Technique for Enhanced Sensitivity of Spectral Domain Optical Coherence Tomography

      Optical Interferometric Fringe Pattern-Incorporated Spectrum Calibration Technique for Enhanced Sensitivity of Spectral Domain Optical Coherence Tomography

      Depth-visualizing sensitivity can be degraded due to imperfect optical alignment and non-equidistant distribution of optical signals in the pixel array, which requires a measurement of the re-sampling process. To enhance this depth-visualizing sensitivity, reference and sample arm-channeled spectra corresponding to different depths using mirrors were obtained to calibrate the spectrum sampling prior to Fourier transformation. During the process, eight interferogram patterns corresponding to point spread function (PSF) signals at eight optical path length differences were acquired. To calibrate the spectrum, generated intensity points of the original interferogram were re-indexed towards a maximum intensity range, and these interferogram re-indexing points were ...

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    9. Identification of multi-dimensional thread geometry using depth-resolved swept-source optical coherence tomography for assessment of dental implant fabrication

      Identification of multi-dimensional thread geometry using depth-resolved swept-source optical coherence tomography for assessment of dental implant fabrication

      The geometrical characteristics of dental implants, such as thread depth and width, facing angle, pitch, and surface roughness, are important to assess their stability and osseointegration after implant surgery. Herein, we demonstrate the potential use of depth-resolved swept-source optical coherence tomography (SS-OCT) to assess the structural quality of widely used dental implants. The implemented SS-OCT system was centered at a wavelength of 1300 nm with a 100 nm full-width at half-maximum. Four dental implants with different structural formations fabricated using either titanium or ceramic were visualized. Qualitative assessments were performed using boundary flattening with an amplitude-profiling algorithm to emphasize and ...

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    10. An averaged intensity difference detection algorithm for identification of human gingival sulcus in optical coherence tomography images

      An averaged intensity difference detection algorithm for identification of human gingival sulcus in optical coherence tomography images

      In the past decade, there has been an increase in the development of sensitive, highresolution, non-invasive diagnostic methods for periodontic diseases. Optical coherence tomography (OCT) has attracted considerable attention in clinical settings. In this study, a reliable, robust algorithm for the detection of gingival sulcus in 2D OCT cross-sectional images is proposed. Previously, the measurement of gingival sulcus in OCT images has been performed by manual identification using two-dimensional (2D) cross-sectional images. The automated detection of gingival sulcus continuity in 2D OCT images may help medical practitioners to assess important features of gingival tissues. The Sobel and canny operators have ...

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    11. Non-ionized, High-resolution Measurement of Internal and Marginal Discrepancies of Dental Prosthesis Using Optical Coherence Tomography

      Non-ionized, High-resolution Measurement of Internal and Marginal Discrepancies of Dental Prosthesis Using Optical Coherence Tomography

      An internal and marginal fit between prosthesis and abutment are important factors of the durability of dental prosthesis. In this study we have proposed the use of swept-source optical coherence tomography (SS-OCT) as a novel application for non-ionized and high-resolution measurements of internal and marginal discrepancies at anatomically critical four points, such as occlusal, angle, axial, and margin during prosthesis attachment. A tooth model was fabricated by 3D printing technique and the dental prosthesis was designed using dental CAD software. The cross-sectional images along with intensity peak profile analysis of the sample were acquired using OCT system for measurements of ...

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    12. Clinical Utility of Intraoperative Tympanomastoidectomy Assessment Using a Surgical Microscope Integrated with an Optical Coherence Tomography

      Clinical Utility of Intraoperative Tympanomastoidectomy Assessment Using a Surgical Microscope Integrated with an Optical Coherence Tomography

      Significant technical and optical advances are required for intraoperative optical coherence tomography (OCT) to be utilized during otological surgeries. Integrating OCT with surgical microscopy makes it possible to evaluate soft tissue in real-time and at a high resolution. Herein, we describe an augmented-reality, intraoperative OCT/microscope system with an extended working distance of 280 mm, providing more space for surgical manipulation than conventional techniques. We initially performed ex vivo experiments to evaluate system performance. In addition, we validated the system by performing preliminary clinical assessments of tympanomastoidectomy outcomes in six patients with chronic otitis media. The system evaluated residual inflammation ...

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    13. Non-destructive identification of weld-boundary and porosity formation during laser transmission welding by using optical coherence tomography

      Non-destructive identification of weld-boundary and porosity formation during laser transmission welding by using optical coherence tomography

      Laser transmission welding offers significant benefits over conventional welding techniques enabling single-stage rapid plastic joining. The quality of laser transmission welded products are commonly assessed by measuring the weld penetration depth, hardened weld boundary, and inspecting the formation of porosity. However, existing methods of verification are inevitably accompanied by destruction of the specimen. Thus, non-destructive quality assessment methods for laser transmission welding have gained attention recently. Here, we demonstrated an extended industrial application of 860 nm wavelength based spectral domain optical coherence tomography for the non-destructive inspection of the aforementioned quality parameters of laser transmission welded industrial plastic materials, i ...

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    14. Multiple Wavelength Optical Coherence Tomography Assessments for Enhanced Ex Vivo Intra-Cochlear Microstructural Visualization

      Multiple Wavelength Optical Coherence Tomography Assessments for Enhanced Ex Vivo Intra-Cochlear Microstructural Visualization

      The precise identification of intra-cochlear microstructures is an essential otorhinolaryngological requirement to diagnose the progression of cochlea related diseases. Thus, we demonstrated an experimental procedure to investigate the most optimal wavelength range, which can enhance the visualization of ex vivo intra-cochlear microstructures using multiple wavelengths (i.e., 860 nm, 1060 nm, and 1300 nm) based optical coherence tomography (OCT) systems. The high-resolution tomograms, volumetric, and quantitative evaluations obtained from Basilar membrane, organ of Corti, and scala vestibule regions revealed complementary comparisons between the aforementioned three distinct wavelengths based OCT systems. Compared to 860 nm and 1300 nm wavelengths, 1060 nm ...

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    15. In Vivo Fascicle Bifurcation Imaging of Rat Sciatic Nerve Using Swept-Source Optical Coherence Tomography

      In Vivo Fascicle Bifurcation Imaging of Rat Sciatic Nerve Using Swept-Source Optical Coherence Tomography

      The sciatic nerve is the longest and widest single nerve in the human body and is responsible for the signal transduction of the entire hind limb region. Its wide nerve dynamic range and size makes it sensitive to injury. The branching and location of the sciatic nerve are important, and unlike histology, optical coherence tomography (OCT) can provide rapid non-destructive cross-sectional images. The sciatic nerves of ten rats were analyzed using swept-source (SS)-OCT. The sufficient depth penetration of the SS-OCT system allowed clear identification of the internal bifurcation point of the external branching and the internal route for the ...

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    16. Defect inspection of actuator lenses using swept-source optical coherence tomography

      Defect inspection of actuator lenses using swept-source optical coherence tomography

      Actuator lens industries have gained an enormous interest with the enhancement of various latest communication devices, such as mobile phone and notebooks. The quality of the aforementioned devices can be degraded due to the internal defects of actuator lenses. Therefore, in this study, we implemented swept-source optical coherence tomography (SS-OCT) system to inspect defects of actuator lenses. Owing to the high-resolution of the SS-OCT system, defected foreign substances between the actuator lenses, defective regions of lenses and surface stains were more clearly distinguished through three-dimensional (3D) and two-dimensional (2D) cross-sectional OCT images. Therefore, the implemented SS-OCT system can be considered ...

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    17. Decalcification using ethylenediaminetetraacetic acid for clear microstructure imaging of cochlea through optical coherence tomography

      Decalcification using ethylenediaminetetraacetic acid for clear microstructure imaging of cochlea through optical coherence tomography

      The aim of this study was to analyze the effectiveness of decalcification using ethylenediaminetetraacetic acid (EDTA) as an optical clearing method to enhance the depth visibility of internal soft tissues of cochlea. Ex vivo mouse and guinea pig cochlea samples were soaked in EDTA solutions for decalcification, and swept source optical coherence tomography (OCT) was used as imaging modality to monitor the decalcified samples consecutively. The monitored noninvasive cross-sectional images showed that the mouse and guinea pig cochlea samples had to be decalcified for subsequent 7 and 14 days, respectively, to obtain the optimal optical clearing results. Using this method ...

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    1-17 of 17
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    1. (16 articles) Kyungpook National University
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    Decalcification using ethylenediaminetetraacetic acid for clear microstructure imaging of cochlea through optical coherence tomography Defect inspection of actuator lenses using swept-source optical coherence tomography In Vivo Fascicle Bifurcation Imaging of Rat Sciatic Nerve Using Swept-Source Optical Coherence Tomography Multiple Wavelength Optical Coherence Tomography Assessments for Enhanced Ex Vivo Intra-Cochlear Microstructural Visualization Clinical Utility of Intraoperative Tympanomastoidectomy Assessment Using a Surgical Microscope Integrated with an Optical Coherence Tomography Non-ionized, High-resolution Measurement of Internal and Marginal Discrepancies of Dental Prosthesis Using Optical Coherence Tomography An averaged intensity difference detection algorithm for identification of human gingival sulcus in optical coherence tomography images Identification of multi-dimensional thread geometry using depth-resolved swept-source optical coherence tomography for assessment of dental implant fabrication Non-invasive optical screening of Streptococcus Pneumonia based inflammatory changes of the tympanic membrane and mastoid mucosa in guinea pig otitis media using optical coherence tomography Vision-Inspection-Synchronized Dual Optical Coherence Tomography for High-Resolution Real-Time Multidimensional Defect Tracking in Optical Thin Film Industry Hybrid registration of retinal fluorescein angiography and optical coherence tomography images of patients with diabetic retinopathy Optical Coherence Tomography Angiography Quality Across Three Multicenter Clinical Studies of Diabetic Retinopathy