The aim of this study was to investigate the relation between ablation efficiency and temperature increase during laser ablation by 1940-nm Tm:fiber laser. The thermal effects of the Tm:fiber laser on the brain tissue was also investigated. The laser beam (200-1000 mW) was delivered from a distance of 0.5 mm to cortical and subcortical regions of the ex vivo ovine brain tissue samples via 400 μm optical fiber. A total of 560 brain samples were irradiated at different settings in continuous-mode or pulsed-mode. In continuous-mode and pulsed-modulated-mode doses were changed with exposure time and on-off cycles respectively, in order to achieve the tissue to absorb the same energy. During lasing temperature changes of the irradiated tissue were recorded by a thermoprobe (thermoprobe is a system which an optical fiber was embedded into a thermocouple). The radiuses of ablation and coagulation zones were measured under microscope. The ablation efficiencies (100xablation/coagulation radius) and rates of temperature change were calculated. A strong correlation between the ablation efficiency and rate of temperature change was presented.

Date Published: 26 February 2013
PDF: 6 pages
Proc. SPIE 8584, Energy-based Treatment of Tissue and Assessment VII, 858407 (26 February 2013); doi: 10.1117/12.2001512

Published in SPIE Proceedings Vol. 8584:
Energy-based Treatment of Tissue and Assessment VII
Thomas P. Ryan, Editor(s)