• Current Optics and Photonics
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• 제3권1호
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• pp.16-21
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• 2019

We present a broad-bandwidth comb-spacing-swept source (CSWS) based on a differential polarization delay line (DPDL) for interferometric three-dimensional (3D) imaging. The comb spacing of the CSWS is repeatedly swept by the tunable DPDL in the multiwavelength source to provide depth-scanning optical coherence tomography (OCT). As the polarization differential delay of the DPDL is tuned from 5 to 15 ps, the comb spacing along the wavelength continuously varies from 1.6 to 0.53 nm, respectively. The wavelength range of various semiconductor optical amplifiers and the cavity feedback ratio of the tunable fiber coupler are experimentally selected to obtain optimal conditions for a broader 3-dB bandwidth of the multiwavelength spectrum and thus provide a higher axial resolution of $35{\mu}m$ in interferometric OCT imaging. The proposed CSWS-OCT has a simple imaging interferometer configuration without reference-path scanning and a simple imaging process without the complex Fourier transform. 3D surface images of a via-hole structure on a printed circuit board and the top surface of a coin were acquired.

• Imaging Science in Dentistry
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• 제49권2호
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• pp.171-176
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• 2019

The available methods for veneer evaluation are limited to clinical and radiographic examinations, which may not allow the appropriate identification of failure. In this report, we demonstrate the use of optical coherence tomography (OCT) as a noninvasive diagnostic and follow-up method to evaluate gingival recovery and the adhesive interface in aesthetic oral rehabilitation involving periodontal plastic surgery and ceramic laminate veneers. OCT was efficient for evaluating both soft and hard tissues, as well as the quality of the adhesive interface. In conclusion, OCT was found to be a promising approach for the professional evaluation of aesthetic oral rehabilitation, as it was capable of generating images that enabled the analysis of gingival recovery and the adhesive interface.

• Bulletin of the Korean Chemical Society
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• 제12권2호
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• pp.193-196
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• 1991

The $^{13}C-NMR$ shifts of a series of para-substituted $8-aryl-tricyclo[3.2.1.0^{2,7}]oct-8-yl$ and $9-aryl-tricyclo[3.3.1.0^{2,8}]-non-9-yl$ cations were measured in $FSO_3H/SO_2ClF\ at\-90^{\circ}$ in order to examine whether the ${\rho}^{C^+}$ values can be used as a measure of the geometric influence on the charge delocalization resulting from ${\rho}$ conjugation in rigid tricyclopropylcarbinyl cations. Plot of the ${\Delta}{\delta}^{C+} shifts against the ${\sigma}^{C+}$ constants revealed excellent linear correlation. The 8-aryl tricyclooctyl systems yielded a ${\rho}^{C+}$ value of -5.00 with r = 0.9962. Previous investigation of the 9-aryl-tricyclononyl systems gave a correlation coefficient of r = 0.9948 with a slope of ${\rho}^{C+}$ = -4.95. A fair parallelism exists between the results of $^{19}F-NMR $ studies and the change of ${\rho}^{C+}$ value in these cations. Consequently, it is established that the ${\rho}^{C+}$ value can be used to explain the mechanism of charge stabilization of the rigid cyclopropylcarbinyl cation such as tricyclo $[3.2.1.0^{2,7}]oct-8-yl$ cation.

• Medical Lasers
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• 제10권3호
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• pp.123-131
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• 2021

Optical imaging modalities with properties of real-time, non-invasive, in vivo, and high resolution for image-guided surgery have been widely studied. In this review, we introduce two optical imaging systems, that could be the core of image-guided surgery and introduce the system configuration, implementation, and operation methods. First, we introduce the optical coherence tomography (OCT) system implemented by our research group. This system is implemented based on a swept-source, and the system has an axial resolution of 11 ㎛ and a lateral resolution of 22 ㎛. Second, we introduce a fluorescence imaging system. The fluorescence imaging system was implemented based on the absorption and fluorescence wavelength of indocyanine green (ICG), with a light-emitting diode (LED) light source. To confirm the performance of the two imaging systems, human malignant melanoma cells were injected into BALB/c nude mice to create a xenograft model and using this, OCT images of cancer and pathological slide images were compared. In addition, in a mouse model, an intravenous injection of indocyanine green was used with a fluorescence imaging system to detect real-time images moving along blood vessels and to detect sentinel lymph nodes, which could be very important for cancer staging. Finally, polarization-sensitive OCT to find the boundaries of cancer in real-time and real-time image-guided surgery using a developed contrast agent and fluorescence imaging system were introduced.

• Journal of Veterinary Science
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• 제24권5호
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• pp.66.1-66.7
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• 2023

Two dogs presented with bilateral pattern-forming corneal opacity. Treatment with topical immunosuppressants was initiated after a complete ophthalmic examination. The response to treatment was assessed by analyzing serial images using slit-lamp biomicroscopy and spectral domain optical coherence tomography (SD-OCT). Both dogs responded to topical immunosuppressants; however, the lesions recurred once the treatment was abated or withdrawn. The most effective immunosuppressant in both dogs was 0.03% tacrolimus ointment. Early and continuous treatment with topical immunosuppressants may be necessary to improve corneal clarity and prevent scarring. SD-OCT could provide useful structural information regarding presumed immune-mediated keratitis and aid in monitoring treatment response.

• 비파괴검사학회지
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• 제31권5호
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• pp.466-471
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• 2011

광 단층촬영기법은 의료영상진단 기기로 최근에 주목받고 있는 분야이다. 현재 병원 초음파보다 공간 해상도가 10-100배 우수하지만 침투깊이가 조직 내에서 1-2 mm로 얇기 때문에 인체 내 장기 이미징을 위하여서 반드시 내시경 기법을 동반하여야 한다. 본 연구를 통하여 고속 광 단층촬영기법을 소개하고 초소형 기전공학 기술을 바탕으로 개발된 내시경을 사용하여 New Zealand white rabbit의 식도와 위장 벽을 3차원으로 이미징한 결과를 고찰하였다. 개발된 내시경에는, 2축 스캔 반사경이 정전기력에 의하여 구동하는 구 동부 위에 위치하여, 입력광을 2축으로 스캔할 수 있도록 하는 구조를 포함하고 있다. 내시경의 외경은 6 mm이며 스캔 반사경의 직경은 1.2 mm 였다. 3.5초 동안 스캔하면서 3차원 이미지를 획득하였다. 3차원 이미지는 200개의 2차원 이미지를 쌓아서 구현되었으며 각각의 2차원 단면이미지는 $200{\times}500$ 픽셀들로 구성되었다. 이미지의 공간해상도는 공기 중에서 8 ${\mu}m$ 였다.

• Restorative Dentistry and Endodontics
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• 제36권5호
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• pp.367-376
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• 2011

치아우식증의 조기 발견은 외과적 삭제를 피하면서, 적절한 치료를 할 수 있는 좋은 기회를 제공한다. 광간섭단층촬영술은 최근 각광받기 시작한 3차원 이미지 기술로서, 안과에서 광학적 생검의 목적으로 빈번히 이용되는 것을 필두로 다양한 의학 분야에 적용되어 왔고, 최근 초기 우식증의 발견에 전도유망하여 다양한 연구가 진행 중이다. 이 기술은 저 상관도 간섭계의 원리에 근거하고 있으며, 장점으로는 비침습적이고, 방사선을 사용하지 않으며, 3차원 이미지 구축이 가능하다는 점이다. 본 연구에서는 광간섭단층촬영술의 원리와 개략적인 개발 과정에 대한 기술과 함께 치아우식증에 관한 연구들에 대하여 고찰해 보았고, 이를 통해 이 기술의 응용 가능성을 확인하였다. 그럼에도 불구하고, 임상적인 유용성을 입증하기 위해서는 몇 가지 기술적 문제를 해결해야 하고, 보다 많은 생체 내 실험이 뒷받침되어야 할 것이다.

• Journal of the Optical Society of Korea
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• 제20권5호
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• pp.607-613
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• 2016

The pleura is known as an end target organ of exposure to toxic environmental materials such as fine particulate matter and asbestos. Moreover, long-term exposure to hazardous materials can eventually lead to fatal lung disease such as diffuse pleural fibrosis or mesothelioma. Chest computed tomography (CT) and ultrasound are gold standard imaging modalities for detection of advanced pleural disease. However, a diagnostic tool for early detection of pleural reaction has not been developed yet due to difficulties in imaging ultra-fine structure of the pleura. Optical coherence tomography (OCT), which provides cross-sectional images of micro tissue structures at a resolution of 2-10 μm, can image the mesothelium with a thickness of ~100 μm and therefore enables investigation of the early pleural reaction. In this study, we induced the early pleural reaction according to a time sequence after pleurodesis using talc, which has been widely used in the clinical field. The pleural reaction in talc grouped according to the time sequence (1st, 2nd, 4th weeks) showed a significant thickening (average thickness: 45 ± 7.5 μm, 80 ± 10.7 μm, 90 ± 12.5 μm), while the pleural reaction in sham and normal groups showed pleural change from normal to minimal thickening (average thickness: 16 ± 5.5 μm, 17 ± 4.5 μm, 15 ± 6.5 μm, and 12 ± 7.5 μm, 13 ± 2.5 μm, 12 ± 3.5 μm). The measurement of pleural reaction by pathologic examinations was well-matched with the measurement by OCT images. This is the first study for measuring the thickness of pleural reactions using a biophotonic modality such as OCT. Our results showed that OCT can be useful for evaluating the early pleural reaction.

• 한국임상수의학회지
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• 제24권3호
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• pp.295-299
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• 2007

체세포 핵이식을 통한 형질전환 소를 생산 시 초기 수정란 발육 시 발생하는 주요 유전자의 이상 발현을 규명을 목적으로 본 연구를 수행하였다. 형질전환 복제수정란의 낮은 발육능의 원인을 규명하기 위해 하기 위하여 단위 발생란, 체외수정란 및 형질전환 복제수정란에서 초기 배 발육에 중요한 유전자인 IFN-t, Oct4 및 Fgf4유전자의 발현량을 비교 분석하였다. RNA는 각각 10개 수정란에서 추출한 후 reverse-transcription하여 first cDNA를 합성하고 이를 가지고 실시간 중합효수 연쇄반응을 실시하였다. IFN-t유전자의 발현은 형질전환 복제란에서 유의적으로 높게 나왔다 (P<0.05).그러나 Oct4 및 Fgf4 유전자의 경우 형질전환 복제란에서 체외수정란에 비해 유의적으로 낮게 나옴을 확인하였다. 이상의 결과로, 형질전환 복제수정란의 낮은 발육능이 원인이 발육에 중요한 유전자의 이상 발현에 기인된다고 사료된다.

• 광학과기술
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• 제17권3호
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• pp.29-33
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• 2013