1. Articles from woonggyu jung

    1-24 of 34 1 2 »
    1. Quantitative evaluation of skin surface roughness using optical coherence tomography in vivo

      Quantitative evaluation of skin surface roughness using optical coherence tomography in vivo

      The quantitative monitoring of skin topography is important in the field of cosmetics and dermatology. The most widespread method for determining skin roughness in vivo is to use skin microrelief, PRIMOS device, which allows a noninvasive, fast and direct measurement of the skin surface. However, it has drawbacks, such as the interference of backscattering from volumetric skin and motion artifacts. In this study, we demonstrate the potential of OCT for providing reliable and quantitative skin surface roughness. In order to evaluate the performance of OCT for skin surface analysis, different types of skin phantoms were fabricated and measured. We utilized ...

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    2. Evaluation of fouling in nanofiltration for desalination using a resistance-in-series model and optical coherence tomography

      Evaluation of fouling in nanofiltration for desalination using a resistance-in-series model and optical coherence tomography

      Resistance-in-series models have been applied to investigate fouling behavior. However, it is difficult to model the influence of morphology on fouling behavior because resistance is indirectly calculated from the water flux and transmembrane pressure. In this study, optical coherence tomography (OCT) was applied to evaluate the resistance of the fouling layer based on fouling morphology. Sodium alginate, humic acid, and bovine serum albumin (BSA) with high salts concentrations (conductivity: 23 mS/cm) were used as model foulants. At the same total fouling resistance, BSA showed the highest cake layer thickness (BSA (114.5 μm) > humic acid (53.5 μm) > sodium ...

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    3. Lamellar keratoplasty using position-guided surgical needle and M-mode optical coherence tomography

      Lamellar keratoplasty using position-guided surgical needle and M-mode optical coherence tomography

      Deep anterior lamellar keratoplasty (DALK) is an emerging surgical technique for the restoration of corneal clarity and vision acuity. The big-bubble technique in DALK surgery is the most essential procedure that includes the air injection through a thin syringe needle to separate the dysfunctional region of the cornea. Even though DALK is a well-known transplant method, it is still challenged to manipulate the needle inside the cornea under the surgical microscope, which varies its surgical yield. Here, we introduce the DALK protocol based on the position-guided needle and M-mode optical coherence tomography (OCT). Depth-resolved 26-gage needle was specially designed, fabricated ...

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    4. Image-guided recording system for spatial and temporal mapping of neuronal activities in brain slice

      Image-guided recording system for spatial and temporal mapping of neuronal activities in brain slice

      In this study, we introduce the novel image-guided recording system (IGRS) for efficient interpretation of neuronal activities in the brain slice. IGRS is designed to combine microelectrode array (MEA) and optical coherence tomography at the customized upright microscope. It allows to record multi-site neuronal signals and image the volumetric brain anatomy in a single body configuration. For convenient interconnection between a brain image and neuronal signals, we developed the automatic mapping protocol which enables for projecting acquired neuronal signals on a brain image. In order to evaluate the performance of IGRS, hippocampal signals of the brain slice were monitored, and ...

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    5. Evaluating the effects of organic matter bioavailability on nanofiltration membrane using real-time monitoring

      Evaluating the effects of organic matter bioavailability on nanofiltration membrane using real-time monitoring

      We studied the influence of bioavailability of organic matter on membrane fouling layer development by comparing the filtration of two feed waters (wetland water and graywater). Dissolved organic carbon (DOC) concentration, size exclusion chromatography (SEC), and fluorescence excitation-emission matrix (FEEM) were used to characterize the bioavailability of organic matter in these water samples during the nanofiltration process. The wetland sample contained a high proportion of humic acid- and fulvic acid-like matter with low bioavailability, whereas the graywater sample comprised substantial amounts of aromatic proteins and microbial byproduct-like matter with high bioavailability. In addition, the molecular size distribution revealed that the ...

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    6. Investigating the influence of organic matter composition on biofilm volumes in reverse osmosis using optical coherence tomography

      Investigating the influence of organic matter composition on biofilm volumes in reverse osmosis using optical coherence tomography

      Biofouling, a critical issue in membrane filtration, is influenced by several factors such as membrane characteristics and feed water quality. The organic matter (OM) composition is known to significantly influence biofilm formation, but few studies on this subject have been reported. Optical coherence tomography (OCT) allows direct monitoring of biofilm development on the membrane surface without the need for membrane autopsy. The purposes of the present study are 1) to quantify biofouling formation on a membrane surface using OCT; 2) to monitor the temporal variation of OM composition during membrane formation; and 3) to investigate the variation of OM composition ...

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    7. In vivo 3D imaging of the human tympanic membrane using a wide-field diagonal-scanning optical coherence tomography probe

      In vivo 3D imaging of the human tympanic membrane using a wide-field diagonal-scanning optical coherence tomography probe

      A wide-field optical coherence tomography (OCT) probe was developed that adapts a diagonal-scanning scheme for three-dimensional (3D) in vivo imaging of the human tympanic membrane. The probe consists of a relay lens to enhance the lateral scanning range up to 7 mm. Motion artifacts that occur with the use of handheld probes were found to be decreased owing to the diagonal-scanning pattern, which crosses the center of the sample to facilitate entire 3D scans. 3D images could be constructed from a small number of two-dimensional OCT images acquired using the diagonal-scanning technique. To demonstrate the usefulness and performance of the ...

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    8. Depth enhancement in spectral domain optical coherence tomography using bidirectional imaging modality with a single spectrometer

      Depth enhancement in spectral domain optical coherence tomography using bidirectional imaging modality with a single spectrometer

      A method for depth enhancement is presented using a bidirectional imaging modality for spectral domain optical coherence tomography (SD-OCT). Two precisely aligned sample arms along with two reference arms were utilized in the optical configuration to scan the samples. Using exemplary images of the optical resolution target, Scotch tape, a silicon sheet with two needles, and a leaf, we demonstrated how the developed bidirectional SD-OCT imaging method increases the ability to characterize depth-enhanced images. The results of the developed system were validated by comparing the images with the standard OCT configuration (single-sample arm setup). Given the advantages of higher resolution ...

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    9. Quantitative monitoring of laser-treated engineered skin using optical coherence tomography

      Quantitative monitoring of laser-treated engineered skin using optical coherence tomography

      Nowadays, laser therapy is a common method for treating various dermatological troubles such as acne and wrinkles because of its efficient and immediate skin enhancement. Although laser treatment has become a routine procedure in medical and cosmetic fields, the prevention of side-effects, such as hyperpigmentation, redness and burning, still remains a critical issue that needs to be addressed. In order to reduce the side-effects while attaining efficient therapeutic outcomes, it is essential to understand the light-skin interaction through evaluation of physiological changes before and after laser therapy. In this study, we introduce a quantitative tissue monitoring method based on optical ...

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    10. Wide-field optical coherence microscopy of the mouse brain slice

      Wide-field optical coherence microscopy of the mouse brain slice

      The imaging capability of optical coherence microscopy (OCM) has great potential to be used in neuroscience research because it is able to visualize anatomic features of brain tissue without labeling or external contrast agents. However, the field of view of OCM is still narrow, which dilutes the strength of OCM and limits its application. In this study, we present fully automated wide-field OCM for mosaic imaging of sliced mouse brains. A total of 308 segmented OCM images were acquired, stitched, and reconstructed as an en-face brain image after intensive imaging processing. The overall imaging area was 11.2 × 7.0 ...

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    11. Lateral resolution enhancement using programmable phase modulator in optical coherence tomography

      Lateral resolution enhancement using programmable phase modulator in optical coherence tomography

      Adaptive optics plays an important role in the correction of high-order aberrations to enhance lateral resolution. An OCT system coupled with a programmable phase modulator is designed to verify lateral resolution improvement. The Hamamatsu high-resolution, non-pixelized, optically addressed light modulator (PAL-SLM) PPM X7550 series is used to correct aberrations, utilizing a simple method based on phase information from OCT images. The advantages of this method are its high simplicity and low cost. A raster scanning technique is adopted to scan samples covered with scattering suspension. Metal lines covered with scattering suspension are imaged, and a respective correction is applied to ...

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    12. Evaluation of the usefulness of three-dimensional optical coherence tomography in a guinea pig model of endolymphatic hydrops induced by surgical obliteration of the endolymphatic duct

      Evaluation of the usefulness of three-dimensional optical coherence tomography in a guinea pig model of endolymphatic hydrops induced by surgical obliteration of the endolymphatic duct

      Optical coherence tomography (OCT) has advanced significantly over the past two decades and is currently used extensively to monitor the internal structures of organs, particularly in ophthalmology and dermatology. We used ethylenediamine tetra-acetic acid (EDTA) to decalcify the bony walls of the cochlea and investigated the inner structures by deep penetration of light into the cochlear tissue using OCT on a guinea pig model of endolymphatic hydrops (EH), induced by surgical obliteration of the endolymphatic duct. The structural and functional changes associated with EH were identified using OCT and auditory brainstem response tests, respectively. We also evaluated structural alterations in ...

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    13. Optical coherence tomography for the diagnosis and evaluation of human otitis media

      Optical coherence tomography for the diagnosis and evaluation of human otitis media

      We report the application of optical coherence tomography (OCT) to the diagnosis and evaluation of otitis media (OM). Whereas conventional diagnostic modalities for OM, including standard and pneumatic otoscopy, are limited to visualizing the surface of the tympanic membrane (TM), OCT effectively reveals the depth-resolved microstructure below the TM with very high spatial resolution, with the potential advantage of its use for diagnosing different types of OM. We examined the use of 840-nm spectral domain-OCT (SD-OCT) clinically, using normal ears and ears with the adhesive and effusion types of OM. Specific features were identified in two-dimensional OCT images of abnormal ...

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    14. Comparison of a MEMS-Based Handheld OCT Scanner With a Commercial Desktop OCT System for Retinal Evaluation

      Comparison of a MEMS-Based Handheld OCT Scanner With a Commercial Desktop OCT System for Retinal Evaluation

      Purpose: The goal of this study was to evaluate the ability of our handheld optical coherence tomography (OCT) scanner to image the posterior and anterior structures of the human eye, and especially the individual layers of the retina, and to compare its diagnostic performance with that of a fixed desktop commercial ophthalmic OCT system. Methods: We compared the clinical imaging results of our handheld OCT with a leading commercial desktop ophthalmic system (RTVue) used in specialist offices. Six patients exhibiting diabetes-related retinal pathology had both eyes imaged with each OCT system. Results: In both sets of images, the structural irregularities ...

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    15. Phase correction using programmable phase modulator (PPM) in optical coherence tomography

      Phase correction using programmable phase modulator (PPM) in optical coherence tomography

      Purpose Adaptive optics is used in optical coherence tomography (OCT) in order to improve lateral resolution based on aberration correction. Methods Experiments were performed to compensate higher order aberrations based on wavefront sensing and correction scheme using adaptive optics. The device utilized for compensation is parallel-aligned nematic liquid crystal spatial light modulator (PAL-SLM), PPM X7550 series. Wavefront of light at the sample path was measured by using OCT for aberration correction. Since the phase information can be obtained from interferogram therefore no additional optics is used. The performance of this device is evaluated for the correction of linear tilt aberration ...

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    16. In vivo imaging of middle-ear and inner-ear microstructures of a mouse guided by SD-OCT combined with a surgical microscope

      In vivo imaging of middle-ear and inner-ear microstructures of a mouse guided by SD-OCT combined with a surgical microscope

      We developed an augmented-reality system that combines optical coherence tomography (OCT) with a surgical microscope. By sharing the common optical path in the microscope and OCT, we could simultaneously acquire OCT and microscope views. The system was tested to identify the middle-ear and inner-ear microstructures of a mouse. Considering the probability of clinical application including otorhinolaryngology, diseases such as middle-ear effusion were visualized using in vivo mouse and OCT images simultaneously acquired through the eyepiece of the surgical microscope during surgical manipulation using the proposed system. This system is expected to realize a new practical area of OCT application.

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    17. Stimulated penetrating keratoplasty using real-time virtual intraoperative surgical optical coherence tomography

      Stimulated penetrating keratoplasty using real-time virtual intraoperative surgical optical coherence tomography

      An intraoperative surgical microscope is an essential tool in a neuro- or ophthalmological surgical environment. Yet, it has an inherent limitation to classify subsurface information because it only provides the surface images. To compensate for and assist in this problem, combining the surgical microscope with optical coherence tomography (OCT) has been adapted. We developed a real-time virtual intraoperative surgical OCT (VISOCT) system by adapting a spectral-domain OCT scanner with a commercial surgical microscope. Thanks to our custom-made beam splitting and image display subsystems, the OCT images and microscopic images are simultaneously visualized through an ocular lens or the eyepiece of ...

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    18. Development of Real-Time Dual-Display Handheld and Bench-Top Hybrid-Mode SD-OCTs

      Development of Real-Time Dual-Display Handheld and Bench-Top Hybrid-Mode SD-OCTs

      Development of a dual-display handheld optical coherence tomography (OCT) system for retina and optic-nerve-head diagnosis beyond the volunteer motion constraints is reported. The developed system is portable and easily movable, containing the compact portable OCT system that includes the handheld probe and computer. Eye posterior chambers were diagnosed using the handheld probe, and the probe could be fixed to the bench-top cradle depending on the volunteers’ physical condition. The images obtained using this handheld probe were displayed in real time on the computer monitor and on a small secondary built-in monitor; the displayed images were saved using the handheld probe ...

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    19. Apparatus for biomedical imaging

      Apparatus for biomedical imaging

      A system that incorporates teachings of the present disclosure may include, for example, a method involving capturing spectral interference from an optical coherence tomography imaging probe comprising a micro-electro-mechanical system (MEMS) scanning mirror, and a partial reflector for supplying images to an image sensor. Additional embodiments are disclosed.

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    20. Optical coherence tomography for the diagnosis of human otitis media

      Optical coherence tomography for the diagnosis of human otitis media

      We report the application of Optical Coherence Tomography (OCT) to various types of human cases of otitis media (OM). Whereas conventional diagnostic modalities for OM, including standard and pneumatic otoscopy, are limited to visualizing the surface information of the tympanic membrane (TM), OCT is able to effectively reveal the depth-resolved microstructural below the TM with a very high spatial resolution. With the potential advantage of using OCT for diagnosing different types of OM, we examined in-vivo the use of 840 nm wavelength, and OCT spectral domain OCT (SDOCT) techniques, in several human cases including normal ears, and ears with adhesive ...

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    21. Optical coherence tomography for advanced screening in the primary care office

      Optical coherence tomography for advanced screening in the primary care office

      Optical coherence tomography (OCT) has long been used as a diagnostic tool in the field of ophthalmology. The ability to observe microstructural changes in the tissues of the eye has proved very effective in diagnosing ocular disease. However, this technology has yet to be introduced into the primary care office, where indications of disease are first encountered. We have developed a portable, handheld imaging probe for use in the primary care setting and evaluated its tissue site accessibility, ability to observe diseased tissue, and screening capabilities in in vivo human patients, particularly for pathologies related to the eye, ear and ...

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    22. Investigation of bacterial biofilm in the human middle ear using optical coherence tomography and acoustic measurements

      Investigation of bacterial biofilm in the human middle ear using optical coherence tomography and acoustic measurements

      Children with chronic otitis media (OM) often have conductive hearing loss which results in communication difficulties and requires surgical treatment. Recent studies have provided clinical evidence that there is a one-to-one correspondence between chronic OM and the presence of a bacterial biofilm behind the tympanic membrane (TM). Here we investigate the acoustic effects of bacterial biofilms, confirmed using optical coherence tomography (OCT), in adult ears. Non-invasive OCT images are collected to visualize the cross-sectional structure of the middle ear, verifying the presence of a biofilm behind the TM. Wideband measurements of acoustic reflectance and impedance (0.2 to 6 [kHz ...

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    23. High Speed SD-OCT System Using GPU Accelerated Mode for in vivo Human Eye Imaging

      High Speed SD-OCT System Using GPU Accelerated Mode for in vivo Human Eye Imaging

      We developed an SD-OCT (Spectral Domain-Optical Coherence Tomography) system which uses a GPU (Graphics Processing Unit) for processing. The image size from the SD-OCT system is 1024 × 512 and the speed is 110 frame/sec in real-time. K-domain linearization, FFT (Fast Fourier Transform), and log scaling were included in the GPU processing. The signal processing speed was about 62 ms using a CPU (Central Processing Unit) and 1.6 ms using a GPU, which is 39 times faster. We performed an in-vivo retinal scan, and reconstructed a 3D visualization based on C-scan images. As a result, there were minimal motion ...

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    24. Noninvasive in vivo optical detection of biofilm in the human middle ear

      Noninvasive in vivo optical detection of biofilm in the human middle ear

      Otitis media (OM), a middle-ear infection, is the most common childhood illness treated by pediatricians. If inadequately treated, OM can result in long-term chronic problems persisting into adulthood. Children with chronic OM or recurrent OM often have conductive hearing loss and communication difficulties and require surgical treatment. Tympanostomy tube insertion, the placement of a small drainage tube in the tympanic membrane (TM), is the most common surgical procedure performed in children under general anesthesia. Recent clinical studies have shown evidence of a direct correspondence between chronic OM and the presence of a bacterial biofilm within the middle ear. Biofilms are ...

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    1-24 of 34 1 2 »
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