Searles Kyle, Shalabi Nabil, Hohert Geoffrey, Gharib Nirvana, Jayhooni Sayed Mohammad Hashem, Lane Pierre M, Takahata Kenichi
School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3 Canada.
Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC V6T 1Z4 Canada.
Biomed Eng Lett. 2024 Feb 19;14(3):583-592. doi: 10.1007/s13534-024-00353-8. eCollection 2024 May.
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 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.
光学相干断层扫描（OCT）因其高分辨率和图像质量，正成为一种更常用的用于疾病检测和治疗的内镜成像方式。为了将OCT用于小腔道的三维成像，在内窥镜探头的远端嵌入一个光学扫描仪以对探测光进行圆周扫描，是实现传统的旋转整个探头方法无法达到的高质量成像的一种有前景的方式。为此，本研究提出了一种空心平面微旋转致动器用作内镜远端扫描仪。这种铁磁流体辅助电磁致动器的小型化设计被制成原型，用作一个完整的360°光学扫描仪，它与一个梯度折射率透镜一起集成在光纤探头的尖端，用于OCT。结果表明，该扫描仪实现了显著改善的动态性能，最高速度达到6500转/分钟，是先前设计报告速度的325%，同时保持在安全使用的热极限以下。该扫描仪被证明能够使用人体手指作为活体组织样本进行实时OCT成像测试。所获取的图像没有显示从电线到扫描仪的阴影，这是因为其空心结构允许探测光穿过致动器主体，并且图像质量足以区分真皮和表皮，同时分辨出单个汗腺，证明了该原型扫描仪设计在内窥镜OCT应用中的有效性。
