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Journal of Biomedical Optics • Open Access

Influence of water layer thickness on hard tissue ablation with pulsed CO2 laser
Author(s): Xianzeng Zhang; Zhenlin Zhan; Haishan Liu; Haibin Zhao; Shusen Xie; Qing Ye

Paper Abstract

The theory of hard tissue ablation reported for IR lasers is based on a process of thermomechanical interaction, which is explained by the absorption of the radiation in the water component of the tissue. The microexplosion of the water is the cause of tissue fragments being blasted from hard tissue. The aim of this study is to evaluate the influence of the interdependence of water layer thickness and incident radiant exposure on ablation performance. A total of 282 specimens of bovine shank bone were irradiated with a pulse CO2 laser. Irradiation was carried out in groups: without a water layer and with a static water layer of thickness ranging from 0.2 to 1.2 mm. Each group was subdivided into five subgroups for different radiant exposures ranging from 18 to 84  J/cm2, respectively. The incision geometry, surface morphology, and microstructure of the cut walls as well as thermal injury were examined as a function of the water layer thickness at different radiant exposures. Our results demonstrate that the additional water layer is actually a mediator of laser-tissue interaction. There exists a critical thickness of water layer for a given radiant exposure, at which the additional water layer plays multiple roles, not only acting as a cleaner to produce a clean cut but also as a coolant to prevent bone heating and reduce thermal injury, but also helping to improve the regularity of the cut shape, smooth the cut surface, and enhance ablation rate and efficiency. The results suggest that desired ablation results depend on optimal selection of both water layer thickness and radiant exposure.

Paper Details

Date Published: 26 March 2012
PDF: 9 pages
J. Biomed. Opt. 17(3) 038003 doi: 10.1117/1.JBO.17.3.038003
Published in: Journal of Biomedical Optics Volume 17, Issue 3
Show Author Affiliations
Xianzeng Zhang, Fujian Normal Univ. (China)
Zhenlin Zhan, Fujian Normal Univ. (China)
Haishan Liu, Fujian Normal Univ. (China)
Haibin Zhao, Fujian Normal Univ. (China)
Shusen Xie, Fujian Normal Univ. (China)
Qing Ye, Fujian Medical Univ. (China)

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