• 한국CDE학회논문집
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• 제20권3호
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• pp.263-268
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• 2015

Due to an increased sitting time in work, lumbar disc disease is one of the most frequent diseases in modern days, and this occasionally requires surgery for treatment. Endoscopic disc surgery, one of the common disc surgeries, requires a process of inserting a guide needle to the target disc for which the insertion path is manually planned by drawing lines on the patient's skin while monitoring the fluoroscopic view of the lumbar. Such procedure inevitably exposes both surgeon and patient to the fluoroscopy radiation emitted from the c-arm for a long time. To reduce the radiation exposure time, this study proposes a computer assisted method of calculating the 3D guide needle path by using 2D c-arm images of the disc in 3 different angles. Additionally, a method of the guide robot control based on the 3D needle path was developed by implementing the Hand-eye Calibration method to calculate the transformation matrix between the c-arm and robot base coordinate systems. The proposed system was then tested for its accuracy.

• 한국광학회지
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• 제21권5호
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• pp.206-213
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• 2010

광 간섭 단층촬영 시스템(OCT)을 위한 소형의 광섬유 도관형 주사장치인 엔도스코프(endoscope catheter)를 제작하였다. 깊이방향 주사장치인 원통형 압전소자(PZT)를 이용한 광경로 지연기는 정현파 1 kHz로 구동하여 시간영역에서 엔도스코프 OCT 영상을 구현하였다. 정현파로 구동한 광경로 지연기의 속도는 6 m/s 이고, 깊이방향 스캐닝의 데이터 획득은 3 mm 기준에서 초당 2000 라인이다. 제작한 엔도스코프로 사람의 손가락 및 귀에 대한 초당 10프레임의 OCT 영상을 성공적으로 획득하였다.

• Journal of Korean Neurosurgical Society
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• 제48권4호
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• pp.380-382
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• 2010

The authors present an extremely rare case of a pseudoaneurysm of the ulnar artery as a complication of a two-portal endoscopic carpal tunnel release (ECTR). A 70-year-old man with chronic renal failure and on maintenance hemodialysis with a left arteriovenous fistula presented with paresthesia of his right hand. A clinical diagnosis of right carpal tunnel syndrome was confirmed by ultrasonography and an electro physiologic study. He underwent two-portal ECTR, and the paresthesia was much improved. However, he presented to us one month after operation with severe pain, a tender mass distal to the right wrist crease and more aggravation of the paresthesia in the ulnar nerve distribution. Doppler ultrasound was performed and revealed a hypo echoic lesion 20 mm in diameter in the right palm, with arterial Doppler flow inside connected to the palmar segment of the ulnar artery. An ulnar artery pseudoaneurysm was diagnosed and treated by ultrasound-guided percutaneous thrombin injection. Transverse color Doppler ultrasound image showed complete thrombosis of the pseudoaneurysm and flow cessation after a total injection of 500 units of thrombin. The symptoms were also improved.

• Journal of the Optical Society of Korea
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• 제15권4호
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• pp.380-385
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• 2011

Common-path interferometers are widely used for endoscopic optical coherence tomography (OCT) because an arbitrary arm length can be chosen for the endoscopic imaging probe. However, the scheme suffers from the limited range of the sample position distance from the end of the imaging probe because the position between the reference reflector and the sample is limited by the optical path-length difference (OPD) to induce an interference signal. In this study, we developed a novel method for compensating the arbitrary sample position in common-path swept-source OCT by adding an extra Mach-Zehnder interferometer in the post-path of the interfered optical signal. Theoretical analysis and an experimental demonstration of imaging depth tuning for the flexible sample position of an endoscopic OCT image are discussed. After post-tuning of sample position distance, the positioning limitation between the reference reflector and the sample can be solved for various sample positions over a range of 26 mm for the cross-sectional images of a fish eye sample.

• Current Optics and Photonics
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• 제7권4호
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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.

• 로봇학회논문지
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• 제15권4호
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• pp.316-322
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• 2020

Endoscopic spine surgery is an advanced surgical technique for spinal surgery since it minimizes skin incision, muscle damage, and blood loss compared to open surgery. It requires, however, accurate positioning of an endoscope to avoid spinal nerves and to locate the endoscope near the target disk. Before the insertion of the endoscope, a guide needle is inserted to guide it. Also, the result of the surgery highly depends on the surgeons' experience and the patients' CT or MRI images. Thus, for the training, a number of haptic simulators for spinal needle insertion have been developed. But, still, it is difficult to be used in the medical field practically because previous studies require manual segmentation of vertebrae from CT images, and interaction force between the needle and soft tissue has not been considered carefully. This paper proposes AI-based automatic vertebrae CT-image segmentation and haptic rendering method using the proposed need-tissue interaction model. For the segmentation, U-net structure was implemented and the accuracy was 93% in pixel and 88% in IoU. The needle-tissue interaction model including puncture force and friction force was implemented for haptic rendering in the proposed spinal needle insertion simulator.

• 한국멀티미디어학회논문지
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• 제25권3호
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• pp.451-460
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• 2022

Recently, several deep learning studies have been reported to automatically identify the location of diagnostic devices using endoscopic data. In previous studies, there was no design to determine whether the configuration of the dataset resulted in differences in the accuracy in which artificial intelligence models perform image classification. Studies that are based on large amounts of data are likely to have different results depending on the composition of the dataset or its proportion. In this study, we intended to determine the existence and extent of accuracy according to the composition of the dataset by compiling it into three main types using larynx, esophagus, gastroscopy, and laryngeal endoscopy images.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.2-5
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• 2022

사람의 체내 장기는 복잡한 구조로 되어있으며 특히, 소장은 길이가 약 7m 길이를 가지고 있어 내시경 검사가 쉽지 않고 내시경 검사 시 위험도가 높다. 현재는 캡슐 내시경으로 검사를 수행하고 있으며, 검사 시간이 매우 긴 편이다. 의사는 제거된 저장장치를 컴퓨터에 연결해 환자의 캡슐 내시경 영상을 저장 후 프로그램을 사용하여 판독하지만, 캡슐 내시경 검사 결과 영상 길이가 길어 판독 시간이 많이 소요된다. 또한 소장의 경우 융모에 의해 많은 굴곡이 존재해 검사 과정에서 영상의 폐색 영역이나 명암이 뚜렷이 나타나게 되어 검사 시 병변 및 이상징후에 관해 놓치는 경우가 발생할 수 있다. 본 논문에서는 의사의 영상 판독 시간 단축과 진단 신뢰도 향상을 위해 인공신경망을 이용한 소장 캡슐 내시경 병변 검사 보조 방법을 제공한다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.142-145
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• 1997

This paper presents the development of depth extraction algorithm or the 3D Endoscopic Data using a stereo matching method and depth calculation. The purpose of other's algorithms is to reconstruct 3D object surface and make depth map, but a one of this paper is to measure exact depth information on the base of [cm] from camera to object. For this, we carried out camera calibration.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2005년도 추계학술대회 학술발표 논문집 제15권 제2호
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• pp.535-541
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• 2005

It has been suggested that the endoscopic color of intramucosal gastric carcinoma is correlated with mucosal vascularity within the carcinomatous tissue. The development of electronic endoscopy has made it possible to quantitatively measure the mucosal hemoglobin volume, using a hemoglobin index. The aim of this study was to make a software program to calculate the hemoglobin index (IHb) and then investigate whether the mucosal IHb determined from the electronic endoscopic data is a useful marker for evaluating the color of intramucosal gastric carcinoma, in particular with regard to its value for discriminating between the histologic type. The mean values of IHb for the carcinoma (IHb-C) and the mean values of IHb for the surrounding non-cancerous mucosa ( IHb-N) were calculated in 75 intestinal-type and 34 diffuse-type gastric carcinomas. Then, we analyzed the ratio of the IHb-C to IHb-N. The mean IHb-C/IHb-N ratio in the intestinal-type carcinoma group was higher than that in the diffuse-type carcinoma group ($1.28{\pm}0.19$ vs. $0.81{\pm}0.18$, respectively, p<0.001). When the cut-off point of the C/N ratio was set at 1.00, the accuracy rate, the sensitivity, the specificity, and the positive and negative predictive values of a C/N ratio below 1.00 for the differential diagnosis of diffuse-type carcinoma from intestinal-type carcinoma were $94.5\%$, $94.1\%$, $94.7\%$, $88.9\%$ and $97.3\%$, respectively. IHb is useful for quantitative measurement of the endoscopic color in intramucosal gastric carcinoma and the IHb-C/IHb-N ratio would be helpful in distinguishing diffuse-type carcinoma from intestinal -type carcinoma.