1
|
Zhao T, Pham TT, Baker C, Ma MT, Ourselin S, Vercauteren T, Zhang E, Beard PC, Xia W. Ultrathin, high-speed, all-optical photoacoustic endomicroscopy probe for guiding minimally invasive surgery. BIOMEDICAL OPTICS EXPRESS 2022; 13:4414-4428. [PMID: 36032566 PMCID: PMC9408236 DOI: 10.1364/boe.463057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/01/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Photoacoustic (PA) endoscopy has shown significant potential for clinical diagnosis and surgical guidance. Multimode fibres (MMFs) are becoming increasingly attractive for the development of miniature endoscopy probes owing to their ultrathin size, low cost and diffraction-limited spatial resolution enabled by wavefront shaping. However, current MMF-based PA endomicroscopy probes are either limited by a bulky ultrasound detector or a low imaging speed that hindered their usability. In this work, we report the development of a highly miniaturised and high-speed PA endomicroscopy probe that is integrated within the cannula of a 20 gauge medical needle. This probe comprises a MMF for delivering the PA excitation light and a single-mode optical fibre with a plano-concave microresonator for ultrasound detection. Wavefront shaping with a digital micromirror device enabled rapid raster-scanning of a focused light spot at the distal end of the MMF for tissue interrogation. High-resolution PA imaging of mouse red blood cells covering an area 100 µm in diameter was achieved with the needle probe at ∼3 frames per second. Mosaicing imaging was performed after fibre characterisation by translating the needle probe to enlarge the field-of-view in real-time. The developed ultrathin PA endomicroscopy probe is promising for guiding minimally invasive surgery by providing functional, molecular and microstructural information of tissue in real-time.
Collapse
Affiliation(s)
- Tianrui Zhao
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4 Floor, Lambeth Wing St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Truc Thuy Pham
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4 Floor, Lambeth Wing St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Christian Baker
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4 Floor, Lambeth Wing St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Michelle T. Ma
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4 Floor, Lambeth Wing St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Sebastien Ourselin
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4 Floor, Lambeth Wing St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Tom Vercauteren
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4 Floor, Lambeth Wing St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Edward Zhang
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, 67-73 Riding House Street, London W1W 7EJ, UK
| | - Paul C. Beard
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, UK
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London, Charles Bell House, 67-73 Riding House Street, London W1W 7EJ, UK
| | - Wenfeng Xia
- School of Biomedical Engineering and Imaging Sciences, King’s College London, 4 Floor, Lambeth Wing St Thomas’ Hospital, London SE1 7EH, United Kingdom
| |
Collapse
|
2
|
Zhao T, Ma MT, Ourselin S, Vercauteren T, Xia W. Video-rate dual-modal photoacoustic and fluorescence imaging through a multimode fibre towards forward-viewing endomicroscopy. PHOTOACOUSTICS 2022; 25:100323. [PMID: 35028288 PMCID: PMC8741494 DOI: 10.1016/j.pacs.2021.100323] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/18/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
Multimode fibres (MMFs) are becoming increasingly attractive in optical endoscopy as they promise to enable unparallelled miniaturisation, spatial resolution and cost. However, high-speed imaging with wavefront shaping has been challenging. Here, we report the development of a video-rate dual-modal photoacoustic (PA) and fluorescence microscopy probe with a high-speed digital micromirror device (DMD) towards forward-viewing endomicroscopy. Optimal DMD patterns were obtained using a real-valued intensity transmission matrix algorithm to raster-scan a 1.5 μ m-diameter focused beam at the distal fibre tip for imaging. The PA imaging speed and spatial resolution were varied from ∼ 2 to 57 frames per second and from 1.7 to 3 μ m, respectively. Further, high-fidelity PA images of carbon fibres and mouse red blood cells were acquired at unprecedented speed. The capability of dual-modal imaging was demonstrated with phantoms. We anticipate that with further miniaturisation of the ultrasound detector, this probe could be integrated into medical needles to guide minimally invasive procedures.
Collapse
|
3
|
Zhang Z, Yin X, Liu Y, Wang Y, Xin X. Efficient sorting for an orbital angular momentum multiplexing communication link based on a digital micromirror device and a diffuser. OPTICS EXPRESS 2022; 30:6203-6215. [PMID: 35209561 DOI: 10.1364/oe.447517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/16/2022] [Indexed: 06/14/2023]
Abstract
Efficient sorting multiple orbital angular momentum (OAM) spatial modes is a significant step in OAM multiplexing communications. Recently, wavefront shaping (WS) techniques have been implemented to manipulate light scattering through a diffuser. We reported a novel scheme for sorting multiplexed OAM modes faster and more accurately, using the complex amplitude WS based on a digital micromirror device (DMD) through a diffuser to shape the full field (phase and amplitude) of the OAM modes. In this study, we simulate this complex sorter for demultiplexing multiple modes and make a performance comparison with the previous sorter using the phase-only WS. Our results showed that for arbitrary two multiplexed modes, the sorter could achieve a high detection probability of more than 0.99. As the number of the multiplexed modes increases, the detection probability decreases to ∼0.82 when sorting seven modes, which contrasts the ∼0.71 of the phase-only sorters. We also experimentally verified the feasibility, that for arbitrary two modes, the sorter could reach a high detection probability of more than 0.99, and the complex sorter is capable of higher detection probability than the phase-only sorter under the same conditions. Hence, we anticipate that this sorter may potentially be demultiplexing multiple OAM spatial modes efficiently and quickly.
Collapse
|
4
|
Ayoub AB, Psaltis D. High speed, complex wavefront shaping using the digital micro-mirror device. Sci Rep 2021; 11:18837. [PMID: 34552161 PMCID: PMC8458445 DOI: 10.1038/s41598-021-98430-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/07/2021] [Indexed: 11/26/2022] Open
Abstract
Digital micro-mirror devices (DMDs) have been deployed in many optical applications. As compared to spatial light modulators (SLMs), they are characterized by their much faster refresh rates (full-frame refresh rates up to 32 kHz for binary patterns) compared to 120 Hz for most liquid crystal SLMs. DMDs however can only display binary, unipolar patterns and utilize temporal modulation to represent with excellent accuracy multiple gray-levels in display applications. We used the built-in time domain dynamic range representation of the DMD to project 8-bit complex-fields. With this method, we demonstrated 8-bit complex field modulation with a frame time of 38.4 ms (around 0.15 s for the entire complex-field). We performed phase conjugation by compensating the distortions incurred due to propagation through free-space and a scattering medium. For faster modulation speed, an electro-optic modulator was used in synchronization with the DMD in an amplitude modulation mode to create grayscale patterns with frame rate ~ 833 Hz with display time of only 1.2 ms instead of 38.4 ms for time multiplexing gaining a speed up by a factor of 32.
Collapse
Affiliation(s)
- Ahmed B Ayoub
- Optics Laboratory, Ecole Polytechnique Federale de Lausanne (EPFL), 1015, Lausanne, Vaud, Switzerland.
| | - Demetri Psaltis
- Optics Laboratory, Ecole Polytechnique Federale de Lausanne (EPFL), 1015, Lausanne, Vaud, Switzerland
| |
Collapse
|