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Kučikas V, Werner MP, Schmitz-Rode T, Louradour F, van Zandvoort MAMJ. Two-Photon Endoscopy: State of the Art and Perspectives. Mol Imaging Biol 2023; 25:3-17. [PMID: 34779969 PMCID: PMC9971078 DOI: 10.1007/s11307-021-01665-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/15/2021] [Accepted: 10/05/2021] [Indexed: 10/19/2022]
Abstract
In recent years, the demand for non-destructive deep-tissue imaging modalities has led to interest in multiphoton endoscopy. In contrast to bench top systems, multiphoton endoscopy enables subcellular resolution imaging in areas not reachable before. Several groups have recently presented their development towards the goal of producing user friendly plug and play system, which could be used in biological research and, potentially, clinical applications. We first present the technological challenges, prerequisites, and solutions in two-photon endoscopic systems. Secondly, we focus on the applications already found in literature. These applications mostly serve as a quality check of the built system, but do not answer a specific biomedical research question. Therefore, in the last part, we will describe our vision on the enormous potential applicability of adult two-photon endoscopic systems in biological and clinical research. We will thus bring forward the concept that two-photon endoscopy is a sine qua non in bringing this technique to the forefront in clinical applications.
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Affiliation(s)
- Vytautas Kučikas
- Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, Aachen, Germany. .,XLIM Research Institute, Limoges University, CNRS, Limoges, France.
| | - Maximilian P Werner
- Department of Biohybrid and Medical Textiles (BioTex), RWTH Aachen University, Aachen, Germany
| | - Thomas Schmitz-Rode
- Department of Biohybrid and Medical Textiles (BioTex), RWTH Aachen University, Aachen, Germany
| | | | - Marc A M J van Zandvoort
- Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, Aachen, Germany.,Institute for Cardiovascular Diseases CARIM, Department of Molecular Cell Biology, Maastricht University, Maastricht, Netherlands
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2
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Kaur M, Menon C. Submillimeter Sized 2D Electrothermal Optical Fiber Scanner. SENSORS (BASEL, SWITZERLAND) 2022; 23:404. [PMID: 36617001 PMCID: PMC9823315 DOI: 10.3390/s23010404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 12/24/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Optical scanners are used frequently in medical imaging units to examine and diagnose cancers, assist with surgeries, and detect lesions and malignancies. The continuous growth in optics along with the use of optical fibers enables fabrication of imaging devices as small as a few millimeters in diameter. Most forward viewing endoscopic scanners contain an optical fiber acting as cantilever which is vibrated at resonance. In many cases, more than one actuating element is used to vibrate the optical fiber in two directions giving a 2D scan. In this paper, it is proposed to excite the cantilever fiber using a single actuator and scan a 2D region from its vibrating tip. An electrothermal actuator is optimized to provide a bidirectional (horizontal and vertical) displacement to the cantilever fiber placed on it. A periodic current, having a frequency equal to the resonant frequency of cantilever fiber, was passed through the actuator. The continuous expansion and contraction of the actuator enabled the free end of fiber to vibrate in a circle like pattern. A small change in the actuation frequency permitted the scanning of the area inside the circle.
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Affiliation(s)
- Mandeep Kaur
- MENRVA Research Group, Schools of Mechatronic Systems Engineering and Engineering Science, Simon Fraser University, Surrey, BC V3T 0A3, Canada
| | - Carlo Menon
- MENRVA Research Group, Schools of Mechatronic Systems Engineering and Engineering Science, Simon Fraser University, Surrey, BC V3T 0A3, Canada
- Department of Health Sciences and Technology, ETH Zürich, 8092 Zürich, Switzerland
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3
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Double-layer polarization-independent achromatic metasurface array for optical fiber bundle coupling in microendoscope. Sci Rep 2022; 12:20476. [PMID: 36443340 PMCID: PMC9705277 DOI: 10.1038/s41598-022-24785-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 11/21/2022] [Indexed: 11/29/2022] Open
Abstract
Optical fiber bundle-based microendoscope, which is significant in clinical diagnosis and industrial detection, calls for miniaturization of the probe and high-resolution observation. Here, we propose a double-layer metasurface array borrowing the structures of insect compound eyes to meet both requirements instead of traditional optical components. Each unit in the array aims for an incident field of view, focusing light at the center of the fiber end face with no chromatic aberration at the wavelengths of 470 nm, 530 nm and 630 nm. The metasurface array is composed of a series of isotropic TiO2 nanopillars which are special selected after considering resonance mode and angular dispersion characteristics, etched on both sides of a silica substrate, with the individual functions of deflecting and focusing. In image space, numerical aperture (NA) is 0.287 and the particular layout of two layers achieve zero telecentricity theoretically, which meet the requirements of optical fiber bundle coupling. A unit for incident angle of 20° is shown to validate our design approach numerically, which obtains a focused spot close to the diffraction limit. The compact and ultrathin metasurface could greatly reduce the size of the probe in optical fiber bundle based microendoscope while ensuring the imaging quality.
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4
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Confocal laser endomicroscope with distal MEMS scanner for real-time histopathology. Sci Rep 2022; 12:20155. [PMID: 36418439 PMCID: PMC9684518 DOI: 10.1038/s41598-022-24210-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 11/11/2022] [Indexed: 11/25/2022] Open
Abstract
Confocal laser endomicroscopy is an emerging methodology to perform real time optical biopsy. Fluorescence images with histology-like quality can be collected instantaneously from the epithelium of hollow organs. Currently, scanning is performed at the proximal end of probe-based instruments used routinely in the clinic, and flexibility to control the focus is limited. We demonstrate use of a parametric resonance scanner packaged in the distal end of the endomicroscope to perform high speed lateral deflections. An aperture was etched in the center of the reflector to fold the optical path. This design reduced the dimensions of the instrument to 2.4 mm diameter and 10 mm length, allowing for forward passage through the working channel of a standard medical endoscope. A compact lens assembly provides lateral and axial resolution of 1.1 and 13.6 μm, respectively. A working distance of 0 μm and field-of-view of 250 μm × 250 μm was achieved at frame rates up to 20 Hz. Excitation at 488 nm was delivered to excite fluorescein, an FDA-approved dye, to generate high tissue contrast. The endomicroscope was reprocessed using a clinically-approved sterilization method for 18 cycles without failure. Fluorescence images were collected during routine colonoscopy from normal colonic mucosa, tubular adenomas, hyperplastic polyps, ulcerative colitis, and Crohn's colitis. Individual cells, including colonocytes, goblet cells, and inflammatory cells, could be identified. Mucosal features, such as crypt structures, crypt lumens, and lamina propria, could be distinguished. This instrument has potential to be used as an accessory during routine medical endoscopy.
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5
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System-Level Modelling and Simulation of a Multiphysical Kick and Catch Actuator System. ACTUATORS 2021. [DOI: 10.3390/act10110279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper presents a system-level model of a microsystem architecture deploying cooperating microactuators. An assembly of a piezoelectric kick-actuator and an electromagnetic catch-actuator manipulates a structurally unconnected, magnetized micromirror. The absence of mechanical connections allows for large deflections and multistability. Closed-loop feedback control allows this setup to achieve high accuracy, but requires fast and precise system-level models of each component. Such models can be generated directly from large-scale finite element (FE) models via mathematical methods of model order reduction (MOR). A special challenge lies in reducing a nonlinear multiphysical FE model of a piezoelectric kick-actuator and its mechanical contact to a micromirror, which is modeled as a rigid body. We propose to separate the actuator–micromirror system into two single-body systems. This step allows us to apply the contact-induced forces as inputs to each sub-system and, thus, avoid the nonlinear FE model. Rather, we have the linear model with nonlinear input, to which established linear MOR methods can be applied. Comparisons between the reference FE model and the reduced order model demonstrate the feasibility of the proposed methodology. Finally, a system-level simulation of the whole assembly, including two actuators, a micromirror and a simple control circuitry, is presented.
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6
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Kaur M, Lane PM, Menon C. Scanning and Actuation Techniques for Cantilever-Based Fiber Optic Endoscopic Scanners-A Review. SENSORS 2021; 21:s21010251. [PMID: 33401728 PMCID: PMC7795415 DOI: 10.3390/s21010251] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/30/2020] [Accepted: 12/30/2020] [Indexed: 01/20/2023]
Abstract
Endoscopes are used routinely in modern medicine for in-vivo imaging of luminal organs. Technical advances in the micro-electro-mechanical system (MEMS) and optical fields have enabled the further miniaturization of endoscopes, resulting in the ability to image previously inaccessible small-caliber luminal organs, enabling the early detection of lesions and other abnormalities in these tissues. The development of scanning fiber endoscopes supports the fabrication of small cantilever-based imaging devices without compromising the image resolution. The size of an endoscope is highly dependent on the actuation and scanning method used to illuminate the target image area. Different actuation methods used in the design of small-sized cantilever-based endoscopes are reviewed in this paper along with their working principles, advantages and disadvantages, generated scanning patterns, and applications.
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Affiliation(s)
- Mandeep Kaur
- MENRVA Research Group, Schools of Mechatronic Systems Engineering and Engineering Science, Simon Fraser University, Surrey, B.C. V3T 0A3, Canada;
- School of Engineering Science, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada;
- Imaging Unit, Integrative Oncology, BC Cancer Research Center, Vancouver, B.C., V5Z 1L3, Canada
| | - Pierre M. Lane
- School of Engineering Science, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada;
- Imaging Unit, Integrative Oncology, BC Cancer Research Center, Vancouver, B.C., V5Z 1L3, Canada
| | - Carlo Menon
- MENRVA Research Group, Schools of Mechatronic Systems Engineering and Engineering Science, Simon Fraser University, Surrey, B.C. V3T 0A3, Canada;
- School of Engineering Science, Simon Fraser University, Burnaby, B.C. V5A 1S6, Canada;
- Correspondence:
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A Silicon Optical Bench-Based Forward-View Two-Axis Scanner for Microendoscopy Applications. MICROMACHINES 2020; 11:mi11121051. [PMID: 33260524 PMCID: PMC7761163 DOI: 10.3390/mi11121051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 11/25/2020] [Accepted: 11/27/2020] [Indexed: 02/07/2023]
Abstract
Optical microendoscopy enabled by a microelectromechanical system (MEMS) scanning mirror offers great potential for in vivo diagnosis of early cancer inside the human body. However, an additional beam folding mirror is needed for a MEMS mirror to perform forward-view scanning, which drastically increases the diameter of the resultant MEMS endoscopic probe. This paper presents a new monolithic two-axis forward-view optical scanner that is composed of an electrothermally driven MEMS mirror and a beam folding mirror both vertically standing and integrated on a silicon substrate. The mirror plates of the two mirrors are parallel to each other with a small distance of 0.6 mm. The laser beam can be incident first on the MEMS mirror and then on the beam folding mirror, both at 45°. The MEMS scanner has been successfully fabricated. The measured optical scan angles of the MEMS mirror were 10.3° for the x axis and 10.2° for the y axis operated under only 3 V. The measured tip-tilt resonant frequencies of the MEMS mirror were 1590 Hz and 1850 Hz, respectively. With this compact MEMS design, a forward-view scanning endoscopic probe with an outer diameter as small as 2.5 mm can be made, which will enable such imaging probes to enter the subsegmental bronchi of an adult patient.
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8
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Endoscopic Optical Imaging Technologies and Devices for Medical Purposes: State of the Art. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10196865] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The growth and development of optical components and, in particular, the miniaturization of micro-electro-mechanical systems (MEMSs), has motivated and enabled researchers to design smaller and smaller endoscopes. The overarching goal of this work has been to image smaller previously inaccessible luminal organs in real time, at high resolution, in a minimally invasive manner that does not compromise the comfort of the subject, nor introduce additional risk. Thus, an initial diagnosis can be made, or a small precancerous lesion may be detected, in a small-diameter luminal organ that would not have otherwise been possible. Continuous advancement in the field has enabled a wide range of optical scanners. Different scanning techniques, working principles, and the applications of endoscopic scanners are summarized in this review.
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Hwang K, Seo YH, Kim DY, Ahn J, Lee S, Han KH, Lee KH, Jon S, Kim P, Yu KE, Kim H, Kang SH, Jeong KH. Handheld endomicroscope using a fiber-optic harmonograph enables real-time and in vivo confocal imaging of living cell morphology and capillary perfusion. MICROSYSTEMS & NANOENGINEERING 2020; 6:72. [PMID: 34567682 PMCID: PMC8433427 DOI: 10.1038/s41378-020-00182-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 03/04/2020] [Accepted: 05/14/2020] [Indexed: 06/13/2023]
Abstract
Confocal laser endomicroscopy provides high potential for noninvasive and in vivo optical biopsy at the cellular level. Here, we report a fully packaged handheld confocal endomicroscopic system for real-time, high-resolution, and in vivo cellular imaging using a Lissajous scanning fiber-optic harmonograph. The endomicroscopic system features an endomicroscopic probe with a fiber-optic harmonograph, a confocal microscope unit, and an image signal processor. The fiber-optic harmonograph contains a single mode fiber coupled with a quadrupole piezoelectric tube, which resonantly scans both axes at ~ 1 kHz to obtain a Lissajous pattern. The fiber-optic harmonograph was fully packaged into an endomicroscopic probe with an objective lens. The endomicroscopic probe was hygienically packaged for waterproofing and disinfection of medical instruments within a 2.6-mm outer diameter stainless tube capable of being inserted through the working channel of a clinical endoscope. The probe was further combined with the confocal microscope unit for indocyanine green imaging and the image signal processor for high frame rate and high density Lissajous scanning. The signal processing unit delivers driving signals for probe actuation and reconstructs confocal images using the auto phase matching process of Lissajous fiber scanners. The confocal endomicroscopic system was used to successfully obtain human in vitro fluorescent images and real-time ex vivo and in vivo fluorescent images of the living cell morphology and capillary perfusion inside a single mouse.
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Affiliation(s)
- Kyungmin Hwang
- Department of Bio and Brain Engineering, KAIST and KAIST Institute of Health Science and Technology, Daejeon, 34141 Republic of Korea
- VPIX Medical, Inc, Deajeon, 34141 Republic of Korea
| | - Yeong-Hyeon Seo
- Department of Bio and Brain Engineering, KAIST and KAIST Institute of Health Science and Technology, Daejeon, 34141 Republic of Korea
| | - Daniel Y. Kim
- Department of Bio and Brain Engineering, KAIST and KAIST Institute of Health Science and Technology, Daejeon, 34141 Republic of Korea
| | - Jinhyo Ahn
- Graduate School of Nanoscience and Technology, KAIST and KAIST Institute of Health Science and Technology, Daejeon, 34141 Republic of Korea
| | - Soyoung Lee
- Department of Biological Sciences, KAIST and KAIST Institute for the BioCentury, Daejeon, 34141 Republic of Korea
| | | | - Koun-Hee Lee
- VPIX Medical, Inc, Deajeon, 34141 Republic of Korea
| | - Sangyong Jon
- Department of Biological Sciences, KAIST and KAIST Institute for the BioCentury, Daejeon, 34141 Republic of Korea
| | - Pilhan Kim
- Graduate School of Nanoscience and Technology, KAIST and KAIST Institute of Health Science and Technology, Daejeon, 34141 Republic of Korea
- Graduate School of Medical Science and Engineering, Daejeon, 34141 Republic of Korea
| | - Kate E. Yu
- VPIX Medical, Inc, Deajeon, 34141 Republic of Korea
| | - Hyungsin Kim
- Department of Neurosurgery, Korea University Anam Hospital, Korea University Medicine, Seoul, 02842 Korea
| | - Shin-Hyuk Kang
- Department of Neurosurgery, Korea University Anam Hospital, Korea University Medicine, Seoul, 02842 Korea
| | - Ki-Hun Jeong
- Department of Bio and Brain Engineering, KAIST and KAIST Institute of Health Science and Technology, Daejeon, 34141 Republic of Korea
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10
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Tanguy QAA, Gaiffe O, Passilly N, Cote JM, Cabodevila G, Bargiel S, Lutz P, Xie H, Gorecki C. Real-time Lissajous imaging with a low-voltage 2-axis MEMS scanner based on electrothermal actuation. OPTICS EXPRESS 2020; 28:8512-8527. [PMID: 32225475 DOI: 10.1364/oe.380690] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 01/29/2020] [Indexed: 05/28/2023]
Abstract
Laser scanning based on Micro-Electro-Mechanical Systems (MEMS) scanners has become very attractive for biomedical endoscopic imaging, such as confocal microscopy or Optical Coherence Tomography (OCT). These scanners are required to be fast to achieve real-time image reconstruction while working at low actuation voltage to comply with medical standards. In this context, we report a 2-axis Micro-Electro-Mechanical Systems (MEMS) electrothermal micro-scannercapable of imaging large fields of view at high frame rates, e.g. from 10 to 80 frames per second. For this purpose, Lissajous scan parameters are chosen to provide the optimal image quality within the scanner capabilities and the sampling rate limit, resulting from the limited A-scan rate of typical swept-sources used for OCT. Images of 233 px × 203 px and 53 px × 53 px at 10 fps and 61 fps, respectively, are experimentally obtained and demonstrate the potential of this micro-scannerfor high definition and high frame rate endoscopic Lissajous imaging.
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11
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Zhou G, Lim ZH, Qi Y, Zhou G. Single-Pixel MEMS Imaging Systems. MICROMACHINES 2020; 11:E219. [PMID: 32093324 PMCID: PMC7074650 DOI: 10.3390/mi11020219] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 11/16/2022]
Abstract
Single-pixel imaging technology is an attractive technology considering the increasing demand of imagers that can operate in wavelengths where traditional cameras have limited efficiency. Meanwhile, the miniaturization of imaging systems is also desired to build affordable and portable devices for field applications. Therefore, single-pixel imaging systems based on microelectromechanical systems (MEMS) is an effective solution to develop truly miniaturized imagers, owing to their ability to integrate multiple functionalities within a small device. MEMS-based single-pixel imaging systems have mainly been explored in two research directions, namely the encoding-based approach and the scanning-based approach. The scanning method utilizes a variety of MEMS scanners to scan the target scenery and has potential applications in the biological imaging field. The encoding-based system typically employs MEMS modulators and a single-pixel detector to encode the light intensities of the scenery, and the images are constructed by harvesting the power of computational technology. This has the capability to capture non-visible images and 3D images. Thus, this review discusses the two approaches in detail, and their applications are also reviewed to evaluate the efficiency and advantages in various fields.
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Affiliation(s)
- Guangcan Zhou
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Zi Heng Lim
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Yi Qi
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Guangya Zhou
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
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12
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Wurster LM, Shah RN, Placzek F, Kretschmer S, Niederleithner M, Ginner L, Ensher J, Minneman MP, Hoover EE, Zappe H, Drexler W, Leitgeb RA, Ataman Ç. Endoscopic optical coherence tomography angiography using a forward imaging piezo scanner probe. JOURNAL OF BIOPHOTONICS 2019; 12:e201800382. [PMID: 30652423 PMCID: PMC7065608 DOI: 10.1002/jbio.201800382] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 05/23/2023]
Abstract
A forward imaging endoscope for optical coherence tomography angiography (OCTA) featuring a piezoelectric fiber scanner is presented. Imaging is performed with an optical coherence tomography (OCT) system incorporating an akinetic light source with a center wavelength of 1300 nm, bandwidth of 90 nm and A-line rate of 173 kHz. The endoscope operates in contact mode to avoid motion artifacts, in particular, beneficial for OCTA measurements, and achieves a transversal resolution of 12 μm in air at a rigid probe size of 4 mm in diameter and 11.3 mm in length. A spiral scan pattern is generated at a scanning frequency of 360 Hz to sample a maximum field of view of 1.3 mm. OCT images of a human finger as well as visualization of microvasculature of the human palm are presented both in two and three dimensions. The combination of morphological tissue contrast with qualitative dynamic blood flow information within this endoscopic imaging approach potentially enables improved early diagnostic capabilities of internal organs for diseases such as bladder cancer.
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Affiliation(s)
- Lara M. Wurster
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to MedicineMedical University of ViennaViennaAustria
| | - Ronak N. Shah
- Gisela and Erwin Sick Chair of Micro‐optics, Department of Microsystems EngineeringUniversity of FreiburgFreiburgGermany
| | - Fabian Placzek
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Simon Kretschmer
- Gisela and Erwin Sick Chair of Micro‐optics, Department of Microsystems EngineeringUniversity of FreiburgFreiburgGermany
| | - Michael Niederleithner
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to MedicineMedical University of ViennaViennaAustria
| | - Laurin Ginner
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to MedicineMedical University of ViennaViennaAustria
| | - Jason Ensher
- INSIGHT Photonics Solution, Inc.LafayetteColorado
| | | | | | - Hans Zappe
- Gisela and Erwin Sick Chair of Micro‐optics, Department of Microsystems EngineeringUniversity of FreiburgFreiburgGermany
| | - Wolfgang Drexler
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Rainer A. Leitgeb
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
- Christian Doppler Laboratory for Innovative Optical Imaging and its Translation to MedicineMedical University of ViennaViennaAustria
| | - Çağlar Ataman
- Gisela and Erwin Sick Chair of Micro‐optics, Department of Microsystems EngineeringUniversity of FreiburgFreiburgGermany
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13
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Kim DY, Hwang K, Ahn J, Seo YH, Kim JB, Lee S, Yoon JH, Kong E, Jeong Y, Jon S, Kim P, Jeong KH. Lissajous Scanning Two-photon Endomicroscope for In vivo Tissue Imaging. Sci Rep 2019; 9:3560. [PMID: 30837501 PMCID: PMC6401070 DOI: 10.1038/s41598-019-38762-w] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 12/31/2018] [Indexed: 12/13/2022] Open
Abstract
An endomicroscope opens new frontiers of non-invasive biopsy for in vivo imaging applications. Here we report two-photon laser scanning endomicroscope for in vivo cellular and tissue imaging using a Lissajous fiber scanner. The fiber scanner consists of a piezoelectric (PZT) tube, a single double-clad fiber (DCF) with high fluorescence collection, and a micro-tethered-silicon-oscillator (MTSO) for the separation of biaxial resonant scanning frequencies. The endomicroscopic imaging exhibits 5 frames/s with 99% in scanning density by using the selection rule of scanning frequencies. The endomicroscopic scanner was compactly packaged within a stainless tube of 2.6 mm in diameter with a high NA gradient-index (GRIN) lens, which can be easily inserted into the working channel of a conventional laparoscope. The lateral and axial resolutions of the endomicroscope are 0.70 µm and 7.6 μm, respectively. Two-photon fluorescence images of a stained kidney section and miscellaneous ex vivo and in vivo organs from wild type and green fluorescent protein transgenic (GFP-TG) mice were successfully obtained by using the endomicroscope. The endomicroscope also obtained label free images including autofluorescence and second-harmonic generation of an ear tissue of Thy1-GCaMP6 (GP5.17) mouse. The Lissajous scanning two-photon endomicroscope can provide a compact handheld platform for in vivo tissue imaging or optical biopsy applications.
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Affiliation(s)
- Daniel Youngsuk Kim
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Kyungmin Hwang
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Jinhyo Ahn
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Yeong-Hyeon Seo
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Jae-Beom Kim
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Soyoung Lee
- Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute for the BioCentury, Daejeon, 34141, Republic of Korea
| | - Jin-Hui Yoon
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Eunji Kong
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Yong Jeong
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Sangyong Jon
- Department of Biological Sciences, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute for the BioCentury, Daejeon, 34141, Republic of Korea
| | - Pilhan Kim
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon, 34141, Republic of Korea.,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea
| | - Ki-Hun Jeong
- Department of Bio and Brain Engineering, KAIST, Daejeon, 34141, Republic of Korea. .,KAIST Institute of Health science and technology, Daejeon, 34141, Republic of Korea.
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MEMS Actuators for Optical Microendoscopy. MICROMACHINES 2019; 10:mi10020085. [PMID: 30682852 PMCID: PMC6412441 DOI: 10.3390/mi10020085] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/26/2018] [Accepted: 12/28/2018] [Indexed: 01/21/2023]
Abstract
Growing demands for affordable, portable, and reliable optical microendoscopic imaging devices are attracting research institutes and industries to find new manufacturing methods. However, the integration of microscopic components into these subsystems is one of today's challenges in manufacturing and packaging. Together with this kind of miniaturization more and more functional parts have to be accommodated in ever smaller spaces. Therefore, solving this challenge with the use of microelectromechanical systems (MEMS) fabrication technology has opened the promising opportunities in enabling a wide variety of novel optical microendoscopy to be miniaturized. MEMS fabrication technology enables abilities to apply batch fabrication methods with high-precision and to include a wide variety of optical functionalities to the optical components. As a result, MEMS technology has enabled greater accessibility to advance optical microendoscopy technology to provide high-resolution and high-performance imaging matching with traditional table-top microscopy. In this review the latest advancements of MEMS actuators for optical microendoscopy will be discussed in detail.
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15
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Seo YH, Hwang K, Kim H, Jeong KH. Scanning MEMS Mirror for High Definition and High Frame Rate Lissajous Patterns. MICROMACHINES 2019; 10:mi10010067. [PMID: 30669314 PMCID: PMC6356757 DOI: 10.3390/mi10010067] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 11/16/2022]
Abstract
Scanning MEMS (micro-electro-mechanical system) mirrors are attractive given their potential use in a diverse array of laser scanning display and imaging applications. Here we report on an electrostatic MEMS mirror for high definition and high frame rate (HDHF) Lissajous scanning. The MEMS mirror comprised a low Q-factor inner mirror and frame mirror, which provided two-dimensional scanning at two similar resonant scanning frequencies with high mechanical stability. The low Q inner mirror enabled a broad frequency selection range. The high definition and high frame rate (HDHF) Lissajous scanning of the MEMS mirror was achieved by selecting a set of scanning frequencies near its resonance with a high greatest common divisor (GCD) and a high total lobe number. The MEMS mirror had resonant scanning frequencies at 5402 Hz and 6702 Hz in x and y directions, respectively. The selected pseudo-resonant frequencies of 5450 Hz and 6700 Hz for HDHF scanning provided 50 frames per second with 94% fill factor in 256 × 256 pixels. This Lissajous MEMS mirror could be utilized for assorted HDHF laser scanning imaging and display applications.
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Affiliation(s)
- Yeong-Hyeon Seo
- Department of Bio and Brain Engineering, KAIST, Daejeon 34141, Korea.
- KAIST Institute for Health Science and Technology, Daejeon 34141, Korea.
| | - Kyungmin Hwang
- Department of Bio and Brain Engineering, KAIST, Daejeon 34141, Korea.
- KAIST Institute for Health Science and Technology, Daejeon 34141, Korea.
| | - Hyunwoo Kim
- Department of Bio and Brain Engineering, KAIST, Daejeon 34141, Korea.
- KAIST Institute for Health Science and Technology, Daejeon 34141, Korea.
| | - Ki-Hun Jeong
- Department of Bio and Brain Engineering, KAIST, Daejeon 34141, Korea.
- KAIST Institute for Health Science and Technology, Daejeon 34141, Korea.
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16
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Schulz-Hildebrandt H, Pfeiffer T, Eixmann T, Lohmann S, Ahrens M, Rehra J, Draxinger W, König P, Huber R, Hüttmann G. High-speed fiber scanning endoscope for volumetric multi-megahertz optical coherence tomography. OPTICS LETTERS 2018; 43:4386-4389. [PMID: 30211870 DOI: 10.1364/ol.43.004386] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
We present a forward-viewing fiber scanning endoscope (FSE) for high-speed volumetric optical coherence tomography (OCT). The reduction in size of the probe was achieved by substituting the focusing optics by an all-fiber-based imaging system which consists of a combination of scanning single-mode fibers, a glass spacer, made from a step-index multi-mode fiber, and a gradient-index fiber. A lateral resolution of 11 μm was achieved at a working distance of 1.2 mm. The newly designed piezo-based FSE has an outer diameter of 1.6 mm and a rigid length of 13.5 mm. By moving the whole imaging optic in spirals for scanning the sample, the beam quality remains constant over the entire field of view with a diameter of 0.8 mm. The scanning frequency was adjusted to 1.22 kHz for use with a 3.28 MHz Fourier domain mode locked OCT system. Densely sampled volumes have been imaged at a rate of 6 volumes per second.
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