Efficacy and predictability of soft tissue ablation using a prototype Raman-shifted alexandrite laser

John A. Kozub; Jin-H. Shen; Karen M. Joos; Ratna Prasad; M. Shane Hutson

doi:10.1117/1.JBO.20.10.105004

12 October 2015 Efficacy and predictability of soft tissue ablation using a prototype Raman-shifted alexandrite laser

John A. Kozub, Jin-H. Shen, Karen M. Joos, Ratna Prasad, M. Shane Hutson

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Journal of Biomedical Optics, Vol. 20, Issue 10, 105004 (October 2015). https://doi.org/10.1117/1.JBO.20.10.105004

Abstract

Previous research showed that mid-infrared free-electron lasers could reproducibly ablate soft tissue with little collateral damage. The potential for surgical applications motivated searches for alternative tabletop lasers providing thermally confined pulses in the 6- to-7-μm wavelength range with sufficient pulse energy, stability, and reliability. Here, we evaluate a prototype Raman-shifted alexandrite laser. We measure ablation thresholds, etch rates, and collateral damage in gelatin and cornea as a function of laser wavelength (6.09, 6.27, or 6.43 μm), pulse energy (up to 3 mJ/pulse), and spot diameter (100 to 600 μm). We find modest wavelength dependence for ablation thresholds and collateral damage, with the lowest thresholds and least damage for 6.09 μm. We find a strong spot-size dependence for all metrics. When the beam is tightly focused (∼100-μm diameter), ablation requires more energy, is highly variable and less efficient, and can yield large zones of mechanical damage (for pulse energies >1 mJ). When the beam is softly focused (∼300-μm diameter), ablation proceeded at surgically relevant etch rates, with reasonable reproducibility (5% to 12% within a single sample), and little collateral damage. With improvements in pulse-energy stability, this prototype laser may have significant potential for soft-tissue surgical applications.

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John A. Kozub, Jin-H. Shen, Karen M. Joos, Ratna Prasad, and M. Shane Hutson "Efficacy and predictability of soft tissue ablation using a prototype Raman-shifted alexandrite laser," Journal of Biomedical Optics 20(10), 105004 (12 October 2015). https://doi.org/10.1117/1.JBO.20.10.105004

Published: 12 October 2015

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