Needle Tip Tracking through Photoluminescence for Minimally Invasive Surgery

Abstract

Minimally invasive surgery continues to prioritize patient safety by improving imaging techniques and tumor detection methods. In this work, an all-optical alternative to the current image based techniques for in vitro minimally invasive procedures has been explored. The technique uses a highly fluorescent marker for the surgical needle to be tracked inside simulated tissues. A series of markers were explored including inorganic (Perovskite and PbS) and organic (carbon dots) nanoparticles and organic dye (Rhodamine 6G) to identify layers of different stiffnesses within a tissue. Rhodamine 6G was chosen based on its high fluorescence signal to track 3D position of a surgical needle in a tissue. The needle was tracked inside homogeneous and inhomogeneous gelatin tissues successfully. This exploratory study of tissue characterization and needle tip tracking using fluorescent markers or photoluminescence technique show potential for real-time application of robot-assisted needle insertions during in vivo procedures.

Keywords: biosensors; fluorescent markers; minimally invasive surgery; needle tip tracking; photoluminescence.

Figure 1

Needle-tip tracking in cuvettes with different density of gelatin samples. Three cuvettes containing homogeneous gelatin samples with highest stiffness (G1), medium stiffness (G2), and least stiffness of gelatin (G3) (a–c). Three-layered gelatin with a straight (SN) or a flexible (FN) needle tip smeared with fluorescent markers (d,e). 3D needle tip tracking in a gelatin sample (f).

Figure 2

Experimental setup of the laser spectroscopy.

Figure 3

Comparison of fluorescent markers in terms of signal to noise ratio. Transmittance spectra for gelatin of different concentrations (a). A comparison of PL signal strength from four fluorescent markers, collected from the flexible needle (FN) tip (b).

Figure 4

Effect of needle types (FN, SN) on the performance of fluorescent markers. Comparison of PL signals from FN and SN through 3 different concentrations of gelatin samples using PbS marker (a) and R6G marker (b).

Figure 5

First attempt to track a needle through G1 using R6G as marker along x-axis. The PL measurements are plotted for different locations of the needle with respect to the excitation laser (a). PL peak intensities at those locations (b).

Figure 6

Tracking of SN through G1 with R6G as marker along x (a), y (b), z (c) directions. PL peak intensities as functions of needle positions along the 3 dimensions (d).

Figure 7

Tracking of SN through a 3-layered gelatin sample along y-axis (a). PL peak intensities as a function of position along y-axis with the dashed arrow showing the direction of scan (b).