Data underlying the publication "Discrete Bevel-Tip Steering in a Wasp-Inspired Needle for Transperineal Laser Ablation"

Supporting information underlying the publication "Discrete Bevel-Tip Steering in a Wasp-Inspired Needle for Transperineal Laser Ablation":
S1 Supplementary Information. Optical fiber evaluation [Appendix.pdf]Inside a needle for TransPerineal Laser Ablation (TPLA), an optical fiber is inserted to transfer the laser energy to the target site (i.e., the tumor of the prostate gland). Therefore, in a steerable TPLA needle, the optical fiber needs to follow a curved trajectory in tandem with the needle’s curvature. Severe deflection of the optical fiber could potentially lead to power loss at the tip due to bending losses within the fiber. Laser light exiting the fiber core and entering the fiber cladding will be absorbed, resulting in a loss of power at the fiber tip. Information on the power output during curved trajectories is crucial for integration of optical fibers in steerable needles, as well as for determining the correct power setting on the laser. The study in this supplementary information file experimentally investigates the impact of guiding an optical fiber along a curved trajectory on its power output.
S2 Data. Raw data of the experiment [Raw data set of the experiment.xlsx]The experiment of this explorative study aimed to investigate the needle’s self-propelling and steering performance in gelatin phantoms whilst guiding a 300-µm optical fiber for TPLA through the needle’s central lumen, resulting in a total needle outer diameter of 0.8 mm. For the self-propelling performance, we calculated the propulsion efficiency. For the steering performance, we used the deflection-to-insertion ratio as a measure. The gelatin concentration (i.e., 10 wt%) and the number of actuation cycles (i.e., 20) were kept constant for all measurements. The experimental setup consisted of the needle with integrated fiber in its lumen, a gelatin phantom on a lightweight low-friction aluminum cart, and a camera to capture the position of the needle in the gelatin. To prevent disturbances from manual actuation and ensure zero external push force, the actuation unit remained stationary, and the gelatin tissue phantom was positioned on a low-friction cart. The principle of self-propelled needle insertion with zero external push force holds if the needle pulls the gelatin phantom toward itself by pulling itself deeper into the gelatin. For every measurement, we captured the needle position with respect to the gelatin phantom at the start of, during, and after 20 actuation cycles. The needle tip's position was recorded using a camera mounted on a tripod, positioned directly above the needle to capture a top-down view of the needle tip within the gelatin phantom. Millimeter graph paper was placed at the bottom surface of the low-friction cart to serve as a reference for the traveled distance of the needle tip relative to the gelatin phantom during the experiments. After each measurement, the needle was removed from the phantom and cleaned with water. Each condition was repeated four times, resulting in a total of 12 measurements.