Distal planar rotary scanner for endoscopic optical coherence tomography

Kyle Searles; Nabil Shalabi; Geoffrey Hohert; Nirvana Gharib; Sayed Mohammad Hashem Jayhooni; Pierre M Lane; Kenichi Takahata

doi:10.1007/s13534-024-00353-8

Distal planar rotary scanner for endoscopic optical coherence tomography

Biomed Eng Lett. 2024 Feb 19;14(3):583-592. doi: 10.1007/s13534-024-00353-8. eCollection 2024 May.

Authors

Kyle Searles¹, Nabil Shalabi², Geoffrey Hohert³, Nirvana Gharib², Sayed Mohammad Hashem Jayhooni², Pierre M Lane³, Kenichi Takahata^{1

2}

Affiliations

¹ School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3 Canada.
² Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 Canada.
³ Integrative Oncology, BC Cancer Research Institute, Vancouver, BC V5Z 4E6 Canada.

PMID: 38645593
PMCID: PMC11026329 (available on 2025-02-19)
DOI: 10.1007/s13534-024-00353-8

Abstract

Optical coherence tomography (OCT) is becoming a more common endoscopic imaging modality for detecting and treating disease given its high resolution and image quality. To use OCT for 3-dimensional imaging of small lumen, embedding an optical scanner at the distal end of an endoscopic probe for circumferential scanning the probing light is a promising way to implement high-quality imaging unachievable with the conventional method of revolving an entire probe. To this end, the present work proposes a hollow and planar micro rotary actuator for its use as an endoscopic distal scanner. A miniaturized design of this ferrofluid-assisted electromagnetic actuator is prototyped to act as a full 360° optical scanner, which is integrated at the tip of a fiber-optic probe together with a gradient-index lens for use with OCT. The scanner is revealed to achieve a notably improved dynamic performance that shows a maximum speed of 6500 rpm, representing 325% of the same reported with the preceding design, while staying below the thermal limit for safe in-vivo use. The scanner is demonstrated to perform real-time OCT using human fingers as live tissue samples for the imaging tests. The acquired images display no shadows from the electrical wires to the scanner, given its hollow architecture that allows the probing light to pass through the actuator body, as well as the quality high enough to differentiate the dermis from the epidermis while resolving individual sweat glands, proving the effectiveness of the prototyped scanner design for endoscopic OCT application.

Keywords: Electromagnetic actuator; Endoscopic probe; Ferrofluid; Optical coherence tomography; Optical scanner.

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