Shape-dimension optimization of contact medical laser delivery systems

TLDR: In this paper, Sttetler et al. proposed an approach to optimize the shape and geometrical dimensions of laser scalpels to minimize tissue damage by means of exception of light leaking through the tapered surface and decrease of distal end inner reflection.

Abstract: The paper deals with a problem of light focusing on the tissue for laser surgery, diagnostic and therapeutics with assistance by tapered tips. Optimization of the shape and geometrical dimensions of laser scalpels sought to minimize tissue damage by means of exception of light leaking through the tapered surface and decrease of distal end inner reflection. These results can be achieved by simultaneous attaching,spherical shape to the front surface of tapered tip also optimization of fiber-tip distance and tip dimensions. Analytical and ray-tracing calculations have been performed for sapphire (n equals 1.75) and silica (n equals 1.45) tip materials and air or saline (n equals 1.33) mediums. The diameter of aperture diaphragm and reflection number of incident beam in the tip have been varied from 1 to 5 fiber core diameter and from 1 to 10, respectively. Several numerical methods for evaluation of tip efficiency for optimized and conventional tips were discussed. Some versions of commercially available tip modernization have been presented. Modification of front surface of the tapered tip increased the angular aperture from 4 degrees to 12 degrees (in air) and from 8 degrees to 15 degrees (in saline) with obviating light leaking in commercial tip by Hans Sttetler SA, Switzerland. Replacement of the contact flat laser scalpel (surgical laser technologies, Malvern, PA) to an optimized one allowed us to increase the taper angle from 1.9 degrees to 10 degrees and produced, therefore, shorter and stronger tip without reducing its optical properties.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.