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Proceedings Paper

Optimization of near-infrared laser tissue welding of porcine cornea: a Monte Carlo-aided dosimetry study
Author(s): Neil S. Patel; Howard E. Savage; Richard B. Rosen M.D.; Rabindra K. Halder; Uladzimir Kartazayeu; Steven A. McCormick M.D.; Alvin Katz; Henry D. Perry M.D.; Robert R. Alfano
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Paper Abstract

Monte Carlo simulations were performed to delineate the role of local fluence rates and absorption in histologic success and tensile strength analysis of laser welding of ocular corneal tissue using an erbium fiber laser system operating at 1455nm wavelength. Porcine cornea was used for in vitro welding, while varying power, scan time, and irradiance. Immediate histologic analysis was performed, as well as tensile strength studies. Simulations were performed using MCML code, with a total of 109 photons started. CONV code was used to convolve the output from MCML for a flat photon beam of 80-800 μ focal spot size and power specified by the experiment. The absorption coefficient, μa, was assumed to reflect that of water, 28.6 cm-1. The scattering coefficient, μs, and anisotropy factor, g, were both neglected due to the poor scattering capabilities of water in the wavelength of the laser beam. Fluence rates were determined and were within 0.3%-4% of surface dose calculations for a beam diameter of 80 μ. Interactive Data Language (IDL) was used to sum the dose for one convolved beam to an experiment with multiple scans across the porcine cornea. Achieving optimal usage of the laser system requires maximal use of the variables (power, scan patterns, scan time, irradiance) available to use, and the correlation between Monte Carlo-aided dosimetry and the histopathological and tensile strength studies was performed. Optimal parameters for use in this 1455 nm laser system can be studied, and will allow users the ability to predict histology scores of welding success and tissue injury based on absorption values. These results can refine our experience with laser tissue welding of porcine cornea and aid in determining optimal delivered dose for successful tissue apposition and minimal adverse thermal heating.

Paper Details

Date Published: 25 April 2005
PDF: 5 pages
Proc. SPIE 5686, Photonic Therapeutics and Diagnostics, (25 April 2005); doi: 10.1117/12.589804
Show Author Affiliations
Neil S. Patel, New York Eye and Ear Infirmary (United States)
Howard E. Savage, New York Eye and Ear Infirmary (United States)
Richard B. Rosen M.D., New York Eye and Ear Infirmary (United States)
Rabindra K. Halder, The City College of The City University of New York (United States)
Uladzimir Kartazayeu, The City College of The City University of New York (United States)
Steven A. McCormick M.D., New York Eye and Ear Infirmary (United States)
Alvin Katz, The City College of The City University of New York (United States)
Henry D. Perry M.D., New York Eye and Ear Infirmary (United States)
Robert R. Alfano, The City College of The City University of New York (United States)

Published in SPIE Proceedings Vol. 5686:
Photonic Therapeutics and Diagnostics
Brian Jet-Fei Wong M.D.; Eugene A. Trowers M.D.; Kenton W. Gregory M.D.; Abraham Katzir; Nikiforos Kollias; Reza S. Malek M.D.; Henry Hirschberg M.D.; Kenneth Eugene Bartels D.V.M.; Steen J. Madsen; Lloyd P. Tate V.D.M.; Lawrence S. Bass M.D.; Werner T. W. de Riese; Karen M. McNally-Heintzelman, Editor(s)

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