Optical Coherence Tomography

1. Introduction

Optical coherence tomography (OCT) is a 3D imaging method based on light reflection and low coherence interferometry. OCT can visualize microstructure, vasculature, and birefringence of tissues non-invasively at high imaging speeds. OCT has been successfully applied to non-invasive 3D examination of the retina in the eye for the detection of retinal diseeases. Endoscopic 3D imaging with miniaturized scanning probes based on optical fibers has been tested in the examination of coronary artery, esophagus, and lung etc. by visualizing 3D microstructure of the internal organs.

광간섭 단층영상 (optical coherence tomography, OCT) 는 빛의 반사를 기반으로 하는 3차원 영상기술 입니다. 빛의 반사도 차이도 생체조직의 미세구조 (10마이크론 이하), 혈관 그리고 편광특성 등을 영상화 할 수 있습니다.

광간섭 단층영상은 비침습적으로 고해상도 영상화가 가능하여 안과 망막 검진 등 의학적 검사 및 치료가이드 기술로 개발되어 왔습니다. 본 연구실에서는 다기능 광간섭 단층영상 기술 개발 그리고 의학적 생물학적 활용을 위한 대비도 해상도 증대 기술 등을 개발하고 있습니다.

Fig. Principles of optical coherence microscopy and representative 3D skin images. 광간섭 단층영상의 원리 및 피부 (손가락)의 3차원 영상 예 (상피,진피 등이 영상화 됨)

2. Development

2.1. Combined optical coherence tomography and two-photon microscopy

Both OCT and TPM are 3D imaging techniques based on different contrast mechanisms of light reflection and fluorescence, respectively. OCT and TPM provides different information of tissues: OCT visualizes microstructure, vasculature, and birefringence of tissues, while TPM does cells, collagen in the extracellular matrix of the same tissues. Combination of the two imaging modalities will visualize the tissue microenvironment more completely. We developed the combined TPM and OCT by using separate light sources for the optimal performance.

2.2. Dark-field polarization sensitive optical coherence tomography (DF-PS-OCT)

PS-OCT is an augmented OCT which can visualize both microstructure and birefringence of tissues. PS-OCT has been used in the detection of myelinated nerves, the assessment of burn damage, and the assessment of cancer extension in the oral cacity. PS-OCT has been useful for detecting birefringent tissue structure and lesions in birefringent tissues. OCT imaging probes have optical windows at the distal end to flatten the tissue surface and tilt the surface to avoid specular reflection from the surface.

skin lesions including skin used in the characterization of burn damage by measuring the decrease of tissue birefringence owing to collagen denaturation.

2.3 Dermoscopy guided MF-OCT

Dermoscopy is a surface microscopy used in the dermatology clinic to examine pigmented skin lesions in high contrasts. OCT combination with dermoscopy provides additional skin information such as depth extension and vasculature abnormality of the skin lesion etc. Both dermoscopy and OCT imaging can be acquired simultaneously by using the dermoscopy as the objective lens.

2.4 Multi-functional OCT (MF-OCT)

Structure, Vasculature, Collagen or muscle (Optical birefringence)

3. Applications

응용

1. 피부과 병변 수술 가이드

2. 안과 각막 이식 수술 가이드