Preclinical evaluation of porcine colon resection using hollow core negative curvature fibre delivered ultrafast laser pulses.

Figure 1 Schematic representation of colon tissue layers.Figure 2 Schematic of the laser system for fibre delivered pulses for tissue resectionFigure 3 Schematic of the laser system for direct laser resection of tissue a) Schematic of the spiral scan pattern at the colon tissue surface during picosecond laser ablation Figure 4 Seven cell NC-HCF fibre (a) cleaved laser launching surface (b) damaged surface (c) image of light confined in a single mode at the end face of HC-NCF (20x zoomed image) (d) single mode beam at the focus of 20 mm focal length lens (20x zoomed image) placed after the HC-NCF.Figure 5 coupling efficiency plot of 7 cell HC-NCFFigure 6 Autocorrelation traces of picosecond laser beam (FWHM = 6ps) with an input pulse energy of ~42 µJ corresponding to ~29 µJ delivered from the output of the HC-NCF (Blue line) showing no significant pulse broadening.Figure 7 Optical spectra of laser beam of 6 ps pulse width and 42 µJ pulse energy. 1.5 meter long HC-NCF delivered beam with 6 ps pulse width and ~29 µJ pulse energy (blue line).Figure 8 (a) and (b) Three-dimensional surface profile of the laser ablated zone, (c) and (d) orthogonal depth profiles of the same crater.Figure 9 Haemotoxylin and eosin (H&E) stained images and 3D profilometric images of laser ablated zones in different tissues using same laser parameters. The applied laser fluences are a & c) 18 J/cm2 b & d) 13 J/cm2 Figure 10 The 3D profilometric image of laser ablated area using HC-NCF delivered pulses on porcine colon samples and histology results of laser ablated area in different tissue sample with same laser parameters a) 21 J/cm2 b) 14 J/cm2 and c) 7 J/cm2 laser fluences. The black line on the image is an artefact after the preparation of sample for histology. The expanded view of maximum thermal damage in each laser ablated tissue is presented in the bottom.