• Clinical Endoscopy
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• v.56 no.6
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• pp.681-692
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• 2023

In general, gastroesophageal reflux disease (GERD) is diagnosed clinically based on typical symptoms and/or response to proton pump inhibitor treatment. Upper gastrointestinal endoscopy is reserved for patients presenting with alarm symptoms, such as dysphagia, odynophagia, significant weight loss, gastrointestinal bleeding, or anorexia; those who meet the criteria for Barrett's esophagus screening; those who report a lack or partial response to proton pump inhibitor treatment; and those with prior endoscopic or surgical anti-reflux interventions. Newer endoscopic techniques are primarily used to increase diagnostic yield and provide an alternative to medical or surgical treatment for GERD. The available endoscopic modalities for the diagnosis of GERD include conventional endoscopy with white-light imaging, high-resolution and high-magnification endoscopy, chromoendoscopy, image-enhanced endoscopy (narrow-band imaging, I- SCAN, flexible spectral imaging color enhancement, blue laser imaging, and linked color imaging), and confocal laser endomicroscopy. Endoscopic techniques for treating GERD include esophageal radiofrequency energy delivery/Stretta procedure, transoral incisionless fundoplication, and endoscopic full-thickness plication. Other novel techniques include anti-reflux mucosectomy, peroral endoscopic cardiac constriction, endoscopic submucosal dissection, and endoscopic band ligation. Currently, many of the new endoscopic techniques are not widely available, and their use is limited to centers of excellence.

• Clinical Endoscopy
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• v.51 no.6
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• pp.527-533
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• 2018

There have been many advances in endoscopic imaging technologies. Magnifying endoscopy with narrow-band imaging is an innovative optical technology that enables the precise discrimination of structural changes on the mucosal surface. Several studies have demonstrated its usefulness and superiority for tumor detection and differential diagnosis in the stomach as compared with conventional endoscopy. Furthermore, magnifying endoscopy with narrow-band imaging has the potential to predict the invasion depth and tumor margins during gastric endoscopic submucosal dissection. Classifications of the findings of magnifying endoscopy with narrow-band imaging based on microvascular and pit patterns have been proposed and have shown excellent correlations with invasion depth confirmed by microscopy. In terms of tumor margin prediction, magnifying endoscopy with narrow-band imaging offers superior delineation of gastric tumor margins compared with traditional chromoendoscopy with indigo carmine. The limitations of narrow-band imaging, such as the need for considerable training, long procedure time, and lack of studies about its usefulness in undifferentiated cancer, should be resolved to confirm its value as a complementary method to endoscopic submucosal dissection. However, the role of magnifying endoscopy with narrow-band imaging is expected to increase steadily with the increasing use of endoscopic submucosal dissection for the treatment of gastric tumors.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.485-497
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• 2017

Surgical treatment of the degenerative disc disease has evolved from traditional open spine surgery to minimally invasive spine surgery including endoscopic spine surgery. Constant improvement in the imaging modality especially with introduction of the magnetic resonance imaging, it is possible to identify culprit degenerated disc segment and again with the discography it is possible to diagnose the pain generator and pathological degenerated disc very precisely and its treatment with minimally invasive approach. With improvements in the optics, high resolution camera, light source, high speed burr, irrigation pump etc, minimally invasive spine surgeries can be performed with various endoscopic techniques for lumbar, cervical and thoracic regions. Advantages of endoscopic spine surgeries are less tissue dissection and muscle trauma, reduced blood loss, less damage to the epidural blood supply and consequent epidural fibrosis and scarring, reduced hospital stay, early functional recovery and improvement in the quality of life & better cosmesis. With precise indication, proper diagnosis and good training, the endoscopic spine surgery can give equally good result as open spine surgery. Initially, endoscopic technique was restricted to the lumbar region but now it also can be used for cervical and thoracic disc herniations. Previously endoscopy was used for disc herniations which were contained without migration but now days it is used for highly up and down migrated disc herniations as well. Use of endoscopic technique in lumbar region was restricted to disc herniations but gradually it is also used for spinal canal stenosis and endoscopic assisted fusion surgeries. Endoscopic spine surgery can play important role in the treatment of adolescent disc herniations especially for the persons who engage in the competitive sports and the athletes where less tissue trauma, cosmesis and early functional recovery is desirable. From simple chemonucleolysis to current day endoscopic procedures the history of minimally invasive spine surgery is interesting. Appropriate indications, clear imaging prior to surgery and preplanning are keys to successful outcome. In this article basic procedures of percutaneous endoscopic lumbar discectomy through transforaminal and interlaminar routes, percutaneous endoscopic cervical discectomy, percutaneous endoscopic posterior cervical foraminotomy and percutaneous endoscopic thoracic discectomy are discussed.

• Current Optics and Photonics
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• v.5 no.5
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• pp.532-537
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• 2021

We present a compact endoscopic probe in a needle form which has a fast beam-scanning capability for optical coherence tomography (OCT). In our study, a beam-scanning OCT imaging needle was fabricated with a 26G syringe needle (0.46 mm in outer diameter) and a thin OCT imaging probe based on the stepwise transitional core (STC) fiber. The imaging probe could freely rotate inside the needle for beam scans. Hence, OCT imaging could be performed without rotation or translation of the needle body. In our design, the structural integrity of the needle's steel tubing was preserved for mechanical robustness. Probing the optical signal was performed through the needle's own window formed at the end. For hand-held operation of our imaging needle, a light and compact scanner module (130 g and 45 × 53 × 60 mm³) was devised. Connected to the imaging needle, it could provide rotational actuation driven by a galvanometer. Because of its finite actuation range, our scanner module did not need a fiber rotary joint which might add undesirable complexity. The beam scan speed was 20 Hz and supported 20 frames per second at the maximum for endoscopic OCT imaging.

• Journal of Digestive Cancer Research
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• v.10 no.1
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• pp.16-21
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• 2022

Diagnosis of gastric subepithelial tumors (SETs) is sometimes difficult with conventional endoscopy or tissue sampling with standard biopsy, so non-invasive imaging modalities such as endoscopic ultrasound (EUS) and computed tomography are used to evaluate the characteristics of SETs features (size, location, originating layer, echogenicity, shape). However imaging modalities alone is not able to distinguish among all types of SETs, so histology is the gold standard for obtaining the final diagnosis. For tissue sampling, mucosal cutting biopsy and mucosal incision-assisted biopsy and EUS-guided fine-needle aspiration or biopsy (EUS-FNA or EUS-FNB) is commonly recommended. Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are used for resection of SETs involving the mucosal and superficial submucosal layers, could not treat adequately and safely the SETs involving the deep mucosa and muscularis propria. Submucosal tunneling endoscopic resection (STER) and endoscopic full-thickness resection (EFTR) is used as a therapeutic option for the treatment of SETs with the development of reliable endoscopic closure techniques and tools.

• Journal of Biomedical Engineering Research
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• v.31 no.5
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• pp.335-343
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• 2010

This article presents a review of technologies for an endoscope. The classification according to the clinical applications and the imaging modalities are summarized. The major parts are focused on describing the gastrointestinal endoscope's structures and mechanisms. The details of the image enhanced endoscopic techniques, such as NBI (narrow band imaging), OCT (optical coherence tomography), and EUS (endoscopic ultrasound), are also explained. Finally, the trend of NOTES (natural orifice transluminal endoscopic surgery) which is new fusion technology in the field of endoscopic diagnosis and surgery is introduced.

• Current Optics and Photonics
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• v.7 no.4
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• pp.398-407
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• 2023

We explored a method to evaluate imaging performance for the optimal assembly of an endoscopic miniature lens and a sensor constituting an imaging module at the distal end of gastrointestinal endoscopy. For the assembly of the imaging module, the image sensor was precisely located at the focal plane when collimated light passed through the endoscopic lens. As another method, the distance between the lens and sensor was adjusted to obtain the highest focus index from images measured the star chart of the International Organization for Standardization (ISO) standard at various positions. We analyzed the slanted-edge modulation transfer function (MTF), corresponding depth of field, and number of line pairs for MTF 50% and 20% at each working distance within the range of 5-100 mm for imaging modules assembled in different ways. Assembly conditions of the imaging module with better MTF performance were defined for each working distance range of 5-30 mm and 30-100 mm, respectively. In addition to the MTF performance, the focus index of each assembled module was also compared. In summary, we examined the performance of imaging modules assembled with different methods within the suggested working distance and tried to establish the optimal assembly protocol.

• Journal of KIEE
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• v.10 no.1
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• pp.1-6
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• 2000

This paper represents the design of 3D endoscopic video system in order to improve visualization and enhance the ability of the surgeon to perform delicate endoscopic surgery. In comparison of the polarized and electric shutter-type stereo imaging system, The former is superior in terms of accuracy and performance speed for knot-tying and loop pass test. The result of experiments show that the proposed 3D endoscopy system has a wide viewing angle and zone which is necessary for multi-view and it has better image quality and stability of the optical performances than the electric shutter-type does.

• Journal of Gastric Cancer
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• v.16 no.3
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• pp.152-160
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• 2016

Purpose: Endoscopic diagnosis of gastric cancer (GC) that emerges after eradication of Helicobacter pylori may be affected by unique morphological changes. Using comprehensive endoscopic imaging, which can reveal biological alterations in gastric mucosa after eradication, previous studies demonstrated that Congo red chromoendoscopy (CRE) might clearly show an acid non-secretory area (ANA) with malignant potential, while autofluorescence imaging (AFI) without drug injection or dyeing may achieve early detection or prediction of GC. We aimed to determine whether AFI might be an alternative to CRE for identification of high-risk areas of gastric carcinogenesis after eradication. Materials and Methods: We included 27 sequential patients with metachronous GC detected during endoscopic surveillance for a mean of 82.8 months after curative endoscopic resection for primary GC and eradication. After their H. pylori infection status was evaluated by clinical interviews and $^{13}C$-urea breath tests, the consistency in the extension of corpus atrophy (e.g., open-type or closed-type atrophy) between AFI and CRE was investigated as a primary endpoint. Results: Inconsistencies in atrophic extension between AFI and CRE were observed in 6 of 27 patients, although CRE revealed all GC cases in the ANA. Interobserver and intraobserver agreements in the evaluation of atrophic extension by AFI were significantly less than those for CRE. Conclusions: We demonstrated that AFI findings might be less reliable for the evaluation of gastric mucosa with malignant potential after eradication than CRE findings. Therefore, special attention should be paid when we clinically evaluate AFI findings of background gastric mucosa after eradication (University Hospital Medical Information Network Center registration number: UMIN000020849).

• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.300-304
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• 2011

Optical microscopes are widely used for medical imaging these days, but biopsy is a lengthy process that causes many problems during the ex-vivo imaging procedure. The endo-microscope has been studied to increase accessibility to the human body and to get in-vivo images to use for medical diagnosis. This research proposes a multi-modal confocal endo-microscope for bio-medical imaging. We introduce the design process for a small endoscopic probe and a coupling mechanism for the probe to make the multi-modal confocal endo-microscope. The endoscopic probe was designed to decrease chromatic and spherical aberrations, which deteriorate the images obtained with the conventional GRIN lens. Fluorescence and reflectance images of various samples were obtained with the proposed endo-microscope. We evaluated the performance of the proposed endo-microscope by analyzing the acquired images, and demonstrate the possibilities of in-vivo medical imaging for early diagnosis.