Probe-based confocal laser endomicroscopy has a high potential to be a promising tool that can provide intraoperative high-resolution in vivo morphological imaging at cellular and subcellular levels for thyroidectomy, and allow real-time assessment of tumor margins. However, the typical images acquired with this technique cover a very small area limited by the field of view of the probe, accompanied by tissue deformation and inconsistent probe-tissue contact when operated manually. In this paper, a novel compact robotic device for large area scanning has been developed. The device can scan a large surface in a spiral trajectory by rotating the tip frame along the spiral groove of the base frame. The fiber Bragg grating sensor with a passive linear structure is used to detect and maintain a stable probe-tissue contact force during scanning. An active linear actuation is also integrated for adjusting the probe-tissue contact level prior to each scan. Results demonstrate that the scanning device ensures a suitable probe-tissue contact force and compensates for simulated hand tremor. Mosaicing results of lens tissue paper and porcine belly tissue with both bench and hand-held experiments show the effectiveness and usability of the device, demonstrating the potential clinical value of the system.
Keywords: Confocal endomicroscopy; Force sensing; Image mosaicing; Mechanical design; Thyroidectomy.