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Shirazi A, Sahraeibelverdi T, Lee M, Li H, Yu J, Jaiswal S, Oldham KR, Wang TD. Miniature side-view dual axes confocal endomicroscope for repetitive in vivo imaging. BIOMEDICAL OPTICS EXPRESS 2023; 14:4277-4295. [PMID: 37799693 PMCID: PMC10549747 DOI: 10.1364/boe.494210] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 06/17/2023] [Accepted: 06/28/2023] [Indexed: 10/07/2023]
Abstract
A side-view dual axes confocal endomicroscope is demonstrated that can be inserted repetitively in hollow organs of genetically engineered mice for in vivo real-time imaging in horizontal and vertical planes. Near infrared (NIR) excitation at λex = 785 nm was used. A monolithic 3-axis parametric resonance scan mirror was fabricated using micro-electro-mechanical systems (MEMS) technology to perform post-objective scanning in the distal end of a 4.19 mm diameter instrument. Torsional and serpentine springs were designed to "switch" the mode of imaging between vertical and horizontal planes by tuning the actuation frequency. This system demonstrated real-time in-vivo images in horizontal and vertical planes with 310 µm depth and 1.75 and 7.5 µm lateral and axial resolution. Individual cells and discrete mucosal structures could be identified.
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Affiliation(s)
- Ahmad Shirazi
- Division of Integrative Systems and Design,
University of Michigan, Ann Arbor, MI
48109, USA
| | | | - Miki Lee
- Department of Internal Medicine, Division
of Gastroenterology, University of
Michigan, Ann Arbor, MI 48109, USA
| | - Haijun Li
- Department of Internal Medicine, Division
of Gastroenterology, University of
Michigan, Ann Arbor, MI 48109, USA
| | - Joonyoung Yu
- Department of Mechanical Engineering,
University of Michigan, Ann Arbor, MI
48109, USA
| | - Sangeeta Jaiswal
- Department of Internal Medicine, Division
of Gastroenterology, University of
Michigan, Ann Arbor, MI 48109, USA
| | - Kenn R Oldham
- Department of Mechanical Engineering,
University of Michigan, Ann Arbor, MI
48109, USA
| | - Thomas D Wang
- Department of Mechanical Engineering,
University of Michigan, Ann Arbor, MI
48109, USA
- Department of Internal Medicine, Division
of Gastroenterology, University of
Michigan, Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering,
University of Michigan, Ann Arbor, MI
48109, USA
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2
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Gunalan A, Mattos LS. Towards OCT-Guided Endoscopic Laser Surgery-A Review. Diagnostics (Basel) 2023; 13:diagnostics13040677. [PMID: 36832167 PMCID: PMC9955820 DOI: 10.3390/diagnostics13040677] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 02/03/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
Optical Coherence Tomography (OCT) is an optical imaging technology occupying a unique position in the resolution vs. imaging depth spectrum. It is already well established in the field of ophthalmology, and its application in other fields of medicine is growing. This is motivated by the fact that OCT is a real-time sensing technology with high sensitivity to precancerous lesions in epithelial tissues, which can be exploited to provide valuable information to clinicians. In the prospective case of OCT-guided endoscopic laser surgery, these real-time data will be used to assist surgeons in challenging endoscopic procedures in which high-power lasers are used to eradicate diseases. The combination of OCT and laser is expected to enhance the detection of tumors, the identification of tumor margins, and ensure total disease eradication while avoiding damage to healthy tissue and critical anatomical structures. Therefore, OCT-guided endoscopic laser surgery is an important nascent research area. This paper aims to contribute to this field with a comprehensive review of state-of-the-art technologies that may be exploited as the building blocks for achieving such a system. The paper begins with a review of the principles and technical details of endoscopic OCT, highlighting challenges and proposed solutions. Then, once the state of the art of the base imaging technology is outlined, the new OCT-guided endoscopic laser surgery frontier is reviewed. Finally, the paper concludes with a discussion on the constraints, benefits and open challenges associated with this new type of surgical technology.
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Affiliation(s)
- Ajay Gunalan
- Department of Advanced Robotics, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
- Department of Informatics, Bioengineering, Robotics and Systems Engineering, University of Genoa, 16145 Genoa, Italy
| | - Leonardo S. Mattos
- Department of Advanced Robotics, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
- Correspondence:
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Lee M, Li H, Birla MB, Li G, Wang TD, Oldham KR. Capacitive Sensing for 2-D Electrostatic MEMS Scanner in a Clinical Endomicroscope. IEEE SENSORS JOURNAL 2022; 22:24493-24503. [PMID: 37497077 PMCID: PMC10367433 DOI: 10.1109/jsen.2022.3216502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
A flexible fiber-coupled confocal laser endomicroscope has been developed using an electrostatic micro-electromechanical system (MEMS) scanner located in at distal optics to collect in vivo images in human subjects. Long transmission lines are required that deliver drive and sense signals with limited bandwidth. Phase shifts have been observed between orthogonal X and Y scanner axes from environmental perturbations, which impede image reconstruction. Image processing algorithms used for correction depend on image content and quality, while scanner calibration in the clinic can be limited by potential patient exposure to lasers. We demonstrate a capacitive sensing method to track the motion of the electrostatically driven two-dimensional MEMS scanner and to extract phase information needed for image reconstruction. This circuit uses an amplitude modulation envelope detection method on shared drive and sensing electrodes of the scanner. Circuit parameters were optimized for performance given high scan frequencies, transmission line effects, and substantial parasitic coupling of drive signal to circuit output. Extraction of phase information further leverages nonlinear dynamics of the MEMS scanner. The sensing circuit was verified by comparing with data from a position sensing detector measurement. The phase estimation showed an accuracy of 2.18° and 0.79° in X and Y axes for motion sensing, respectively. The results indicate that the sensing circuit can be implemented with feedback control for pre-calibration of the scanner in clinical MEMS-based imaging systems.
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Affiliation(s)
- Miki Lee
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Haijun Li
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Mayur B Birla
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Gaoming Li
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Thomas D Wang
- Departments of Internal Medicine, Biomedical Engineering, and Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kenn R Oldham
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, USA
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Wu W, Liu Q, Brandt C, Tang S. Dual-wavelength multimodal multiphoton microscope with SMA-based depth scanning. BIOMEDICAL OPTICS EXPRESS 2022; 13:2754-2771. [PMID: 35774327 PMCID: PMC9203102 DOI: 10.1364/boe.456390] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/19/2022] [Accepted: 03/31/2022] [Indexed: 06/15/2023]
Abstract
We report on a multimodal multiphoton microscopy (MPM) system with depth scanning. The multimodal capability is realized by an Er-doped femtosecond fiber laser with dual output wavelengths of 1580 nm and 790 nm that are responsible for three-photon and two-photon excitation, respectively. A shape-memory-alloy (SMA) actuated miniaturized objective enables the depth scanning capability. Image stacks combined with two-photon excitation fluorescence (TPEF), second harmonic generation (SHG), and third harmonic generation (THG) signals have been acquired from animal, fungus, and plant tissue samples with a maximum depth range over 200 µm.
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Affiliation(s)
- Wentao Wu
- Department of Electrical and Computer Engineering, University of British Columbia, 5500-2332 Main Mall, Vancouver, BC V6 T 1Z4, Canada
| | - Qihao Liu
- Department of Electrical and Computer Engineering, University of British Columbia, 5500-2332 Main Mall, Vancouver, BC V6 T 1Z4, Canada
| | - Christoph Brandt
- Department of Electrical and Computer Engineering, University of British Columbia, 5500-2332 Main Mall, Vancouver, BC V6 T 1Z4, Canada
| | - Shuo Tang
- Department of Electrical and Computer Engineering, University of British Columbia, 5500-2332 Main Mall, Vancouver, BC V6 T 1Z4, Canada
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Herdly L, Janin P, Bauer R, van de Linde S. Tunable Wide-Field Illumination and Single-Molecule Photoswitching with a Single MEMS Mirror. ACS PHOTONICS 2021; 8:2728-2736. [PMID: 34553004 PMCID: PMC8447260 DOI: 10.1021/acsphotonics.1c00843] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Indexed: 06/13/2023]
Abstract
Homogeneous illumination in single-molecule localization microscopy (SMLM) is key for the quantitative analysis of super-resolution images. Therefore, different approaches for flat-field illumination have been introduced as alternative to the conventional Gaussian illumination. Here, we introduce a single microelectromechanical systems (MEMS) mirror as a tunable and cost-effective device for adapting wide-field illumination in SMLM. In flat-field mode the MEMS allowed for consistent SMLM metrics across the entire field of view. Employing single-molecule photoswitching, we developed a simple yet powerful routine to benchmark different illumination schemes on the basis of local emitter brightness and ON-state lifetime. Moreover, we propose that tuning the MEMS beyond optimal flat-field conditions enables to study the kinetics of photoswitchable fluorophores within a single acquisition.
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Affiliation(s)
- Lucas Herdly
- Department
of Physics, SUPA, University of Strathclyde, Glasgow, Scotland, United Kingdom
| | - Paul Janin
- Department
of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, Scotland, United Kingdom
| | - Ralf Bauer
- Department
of Electronic and Electrical Engineering, University of Strathclyde, Glasgow, Scotland, United Kingdom
| | - Sebastian van de Linde
- Department
of Physics, SUPA, University of Strathclyde, Glasgow, Scotland, United Kingdom
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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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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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Lu C, Xiong K, Ma Y, Zhang W, Cheng Z, Yang S. Electrothermal-MEMS-induced nonlinear distortion correction in photoacoustic laparoscopy. OPTICS EXPRESS 2020; 28:15300-15313. [PMID: 32403561 DOI: 10.1364/oe.392493] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/25/2020] [Indexed: 05/18/2023]
Abstract
Micro-electro-mechanical systems (MEMS) scanner has significant advantages of miniature size, fast response and high stability, which is particularly applicable to photoacoustic laparoscopy (PAL). However, tilt angle-voltage curve of electrothermal MEMS shows a nonlinear character, which leads to inevitable nonlinear distortion in photoacoustic imaging. To overcome this problem, a nonlinear distortion correction was developed for the high-resolution forward-scanning electrothermal-MEMS-based PAL. The adaptive resampling method (ARM) was introduced to adaptively calibrate the projection of non-uniform scanning region to match the uniform scanning region. The correction performed low time complexity and high portability owing to the adaptive capacity of distortion decomposition in the reconstruction of physical models. Compared with the sample structure, phantom experiments demonstrated that the distortion was calibrated in all directions and the corrected image provided up to 96.82% high structural similarity in local subset. Furthermore, ARM was applied to imaging the abdominal cavity of rat and the vascular morphology was corrected in real-time display within a delay less than 2 seconds. All these results demonstrated that the nonlinear distortion correction possessed timely and effective correction in PAL, which suggested that it had the potential to employ to any other electrothermal-MEMS-based photoacoustic imaging systems for accurate and quantitative functional imaging.
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Editorial for the Special Issue on MEMS Technology for Biomedical Imaging Applications. MICROMACHINES 2019; 10:mi10090615. [PMID: 31527420 PMCID: PMC6780932 DOI: 10.3390/mi10090615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/10/2019] [Indexed: 01/10/2023]
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10
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2D Au-Coated Resonant MEMS Scanner for NIR Fluorescence Intraoperative Confocal Microscope. MICROMACHINES 2019; 10:mi10050295. [PMID: 31052229 PMCID: PMC6562488 DOI: 10.3390/mi10050295] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/22/2019] [Accepted: 04/26/2019] [Indexed: 02/06/2023]
Abstract
The electrostatic MEMS scanner plays an important role in the miniaturization of the microscopic imaging system. We have developed a new two-dimensional (2D) parametrically-resonant MEMS scanner with patterned Au coating (>90% reflectivity at an NIR 785-nm wavelength), for a near-infrared (NIR) fluorescence intraoperative confocal microscopic imaging system with a compact form factor. A silicon-on-insulator (SOI)-wafer based dicing-free microfabrication process has been developed for mass-production with high yield. Based on an in-plane comb-drive configuration, the resonant MEMS scanner performs 2D Lissajous pattern scanning with a large mechanical scanning angle (MSA, ±4°) on each axis at low driving voltage (36 V). A large field-of-view (FOV) has been achieved by using a post-objective scanning architecture of the confocal microscope. We have integrated the new MEMS scanner into a custom-made NIR fluorescence intraoperative confocal microscope with an outer diameter of 5.5 mm at its distal-end. Axial scanning has been achieved by using a piezoelectric actuator-based driving mechanism. We have successfully demonstrated ex vivo 2D imaging on human tissue specimens with up to five frames/s. The 2D resonant MEMS scanner can potentially be utilized for many applications, including multiphoton microendoscopy and wide-field endoscopy.
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