A Hand-held Instrument to Maintain Steady Tissue Contact during Probe-Based Confocal Laser Endomicroscopy

Abstract

Probe-based confocal laser endomicroscopy (pCLE) provides high-resolution in vivo imaging for intraoperative tissue characterization. Maintaining a desired contact force between target tissue and the pCLE probe is important for image consistency, allowing large area surveillance to be performed. A hand-held instrument that can provide a predetermined contact force to obtain consistent images has been developed. The main components of the instrument include a linear voice coil actuator, a donut load-cell, and a pCLE probe. In this paper, detailed mechanical design of the instrument is presented and system level modeling of closed-loop force control of the actuator is provided. The performance of the instrument has been evaluated in bench tests as well as in hand-held experiments. Results demonstrate that the instrument ensures a consistent predetermined contact force between pCLE probe tip and tissue. Furthermore, it compensates for both simulated physiological movement of the tissue and involuntary movements of the operator's hand. Using pCLE video feature tracking of large colonic crypts within the mucosal surface, the steadiness of the tissue images obtained using the instrument force control is demonstrated by confirming minimal crypt translation.

Endomicroscopy for Computer and Robot Assisted Intervention

“…Coupled with the context of the imaging environment, and real-time methods are necessary Elad et al [66] Mixed L1/L2 optimisation methods to promote sparsity Molina et al [67] Hierarchical variational Bayesian methods to approximate the posterior Pickup et al [68] Integration of registration uncertainty Noonan et al [87] Force adaptive with an embedded 6-axis force/torque sensor (ATI Nano17) Giataganas et al [88] Force-contact probe for integration with surgical robot platforms(da Vinci) Latt et al [89,90] Embedded force sensing into imaging probe Gilbertson et al [91] Incorporate intelligent force control schemes for imaging probe Ang et al [92], Becker et al [93], Maclachlan et al [94] Incorporating tremor cancellation by using piezoelectric actuators combined with visual servoing…”

Toward Intraoperative Breast Endomicroscopy With a Novel Surface-Scanning Device

“…One solution to this problem may be to adopt a more precise set up tube and to avoid an unnecessarily large contact force between the tip and the tissue at the beginning of the scan. The endomicroscopy probe can obtain stable images when the probe tip contact force is between 0.1 N and 0.5 N [32,33]. The bending and rotating forces, which were 0.9 N and 2.1 N respectively, were sufficient in order to carry out a spiral scan.…”

A framework for sensorless and autonomous probe-tissue contact management in robotic endomicroscopic scanning

“…Attempts at automation have been attempted with both active and passive force-control approaches. Probe-tissue contact force management has been attempted using active forcesensing instruments using load cells [6,7], passive forceadaptive instruments with spring-based or pneumatic mechanisms [8,9], distance-sensing [10] and stabilizing mechanisms [11]. But these solutions have certain drawbacks associated with them.…”