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Proceedings Paper

Soft-tissue removal by the 193-nm excimer laser in a strongly absorbing liquid environment
Author(s): Daniel V. Palanker; Itzhak Hemo; Igor Turovets; Aaron Lewis
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Paper Abstract

The 193 nm excimer laser delivered through special tips into biological liquid environments was applied to two different fields of microsurgery and two mechanism of tissue ablation were found to be operative. In vitreoretinal surgical applications, where the tip exit diameter was about 250 micrometers , the effective cutting regime of retina and vitreoretinal membranes occurred at energy fluences of about 250 - 350 mJ/cm2/pulse with a corresponding cutting depth of 50 - 150 micrometers /pulse. Gas bubbles, formed at the tip exit when it touched the tissue during irradiation, seem to be the driving force underlying the cutting process. This enabled us to achieve a much deeper cut in tissue than a micron-sized laser penetration depth. The system was applied to bovine and rabbit retina and rabbit vitreoretinal membranes and it was found that such tissue removal is fast enough for real vitreoretinal applications and the cut depth control is still good enough for this microsurgery. In the application of this system to drilling of 4 - 8 micrometers diameter holes in the zona pellucida of oocytes the optimal energy fluence is about 40 mJ/cm2/pulse with an ablation depth of about 2 micrometers /pulse. In this case no bubbles are formed and the process seems to be a non-explosive photodissociation of the tissue with subsequent slow dissolution of the products. This mechanism, in contrast to the vitreoretinal tissue removal, was found to be very selective to the type of material being ablated. This process was studied on a model of 20% gelatin gel, which is very close to the ablation properties of the zona pellucida.

Paper Details

Date Published: 17 August 1994
PDF: 10 pages
Proc. SPIE 2134, Laser-Tissue Interaction V; and Ultraviolet Radiation Hazards, (17 August 1994); doi: 10.1117/12.182968
Show Author Affiliations
Daniel V. Palanker, Hadassah Hebrew Univ. Hospital (United States)
Itzhak Hemo, Hadassah Hebrew Univ. Hospital (Israel)
Igor Turovets, Hadassah Hebrew Univ. Hospital (Israel)
Aaron Lewis, Hadassah Hebrew Univ. Hospital (Israel)


Published in SPIE Proceedings Vol. 2134:
Laser-Tissue Interaction V; and Ultraviolet Radiation Hazards
Steven L. Jacques; David H. Sliney; Michael Belkin, Editor(s)

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