Lu Chen D, Kraus Martin F, Potsaid Benjamin, Liu Jonathan J, Choi Woojhon, Jayaraman Vijaysekhar, Cable Alex E, Hornegger Joachim, Duker Jay S, Fujimoto James G
Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA.
Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA ; Pattern Recognition Lab and School of Advanced Optical Technologies, University Erlangen-Nuremberg, Erlangen, Germany.
Biomed Opt Express. 2013 Dec 20;5(1):293-311. doi: 10.1364/BOE.5.000293.
We developed an ultrahigh speed, handheld swept source optical coherence tomography (SS-OCT) ophthalmic instrument using a 2D MEMS mirror. A vertical cavity surface-emitting laser (VCSEL) operating at 1060 nm center wavelength yielded a 350 kHz axial scan rate and 10 µm axial resolution in tissue. The long coherence length of the VCSEL enabled a 3.08 mm imaging range with minimal sensitivity roll-off in tissue. Two different designs with identical optical components were tested to evaluate handheld OCT ergonomics. An iris camera aided in alignment of the OCT beam through the pupil and a manual fixation light selected the imaging region on the retina. Volumetric and high definition scans were obtained from 5 undilated normal subjects. Volumetric OCT data was acquired by scanning the 2.4 mm diameter 2D MEMS mirror sinusoidally in the fast direction and linearly in the orthogonal slow direction. A second volumetric sinusoidal scan was obtained in the orthogonal direction and the two volumes were processed with a software algorithm to generate a merged motion-corrected volume. Motion-corrected standard 6 x 6 mm(2) and wide field 10 x 10 mm(2) volumetric OCT data were generated using two volumetric scans, each obtained in 1.4 seconds. High definition 10 mm and 6 mm B-scans were obtained by averaging and registering 25 B-scans obtained over the same position in 0.57 seconds. One of the advantages of volumetric OCT data is the generation of en face OCT images with arbitrary cross sectional B-scans registered to fundus features. This technology should enable screening applications to identify early retinal disease, before irreversible vision impairment or loss occurs. Handheld OCT technology also promises to enable applications in a wide range of settings outside of the traditional ophthalmology or optometry clinics including pediatrics, intraoperative, primary care, developing countries, and military medicine.
我们开发了一种使用二维微机电系统（MEMS）镜的超高速手持式扫频源光学相干断层扫描（SS-OCT）眼科仪器。中心波长为1060 nm的垂直腔面发射激光器（VCSEL）在组织中产生了350 kHz的轴向扫描速率和10 µm的轴向分辨率。VCSEL的长相干长度在组织中实现了3.08 mm的成像范围，且灵敏度下降最小。测试了两种具有相同光学组件的不同设计，以评估手持式OCT的人体工程学。虹膜相机有助于使OCT光束穿过瞳孔对准，手动固定光选择视网膜上的成像区域。从5名未散瞳的正常受试者获得了体积扫描和高分辨率扫描。通过在快速方向上正弦扫描直径2.4 mm的二维MEMS镜并在正交的慢速方向上线性扫描来采集体积OCT数据。在正交方向上获得第二次体积正弦扫描，并使用软件算法处理这两个体积以生成合并的运动校正体积。使用两次体积扫描生成运动校正的标准6×6 mm²和宽视野10×10 mm²体积OCT数据，每次扫描在1.4秒内完成。通过对在0.57秒内在同一位置获得的25次B扫描进行平均和配准，获得了10 mm和6 mm的高分辨率B扫描。体积OCT数据的优点之一是生成具有与眼底特征配准的任意横截面B扫描的正面OCT图像。这项技术应能在不可逆的视力损害或丧失发生之前，实现筛查应用以识别早期视网膜疾病。手持式OCT技术还有望在传统眼科或验光诊所之外的广泛环境中实现应用，包括儿科、术中、初级保健、发展中国家和军事医学。
