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Optoacoustic monitoring of cutting and heating processes during laser ablation.
In: SPIE Photons Plus Ultrasound: Imaging and Sensing 2013 (Conference Photons Plus Ultrasound: Imaging and Sensing, San Francisco USA, 3-5 February 2013). Washington, USA: Society of Photo-Optical Instrumentation Engineers, 2013.:85813X (Proc. SPIE ; 8581)
Laser-tissue interaction during laser surgery can be classified into two biophysical processes: tissue removal in the focal zone of the laser beam and heating in the surrounding tissue. In order to ensure a precise cut and minimal collateral thermal damage, the surgeon has to control several parameters, such as power, repetition rate and fiber movement velocity. In this study we propose utilizing optoacoustics for providing the necessary real-time feedback of cutting and heating processes. A single Q-switched Nd-YAG laser (532nm, 4 KHz, 18 W, pulse duration 7.6ns) was used for ablation and generation of optoacoustic signals in fresh bovine tissue samples. Both shockwaves, generated due to tissue removal, as well as normal optoacoustic responses from the surrounding tissue were detected using a single 10MHz piezoelectric transducer. It has been observed that rapid reduction in the shockwave amplitude occurs as more material is being removed from the focal zone, indicating decrease in cutting efficiency of the laser beam, whereas gradual decrease in the optoacoustic signal likely corresponds to coagulation around the ablation crater. Further heating of surrounding tissue leads to carbonization accompanied by a significant shift of spectral components of the optoacoustic signal. Our results hold promise for real-time monitoring of cutting efficiency and collateral thermal damage during laser surgery.
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Publication type Article: Conference contribution
Keywords Feedback ; Laser ablation ; Lasers ; Nd:YAG lasers ; Q switching ; Surgery ; Tissues ; Transducers
Conference Title Conference Photons Plus Ultrasound: Imaging and Sensing, San Francisco USA, 3-5 February 2013
Proceedings Title SPIE Photons Plus Ultrasound: Imaging and Sensing 2013
Quellenangaben Volume: 8581, Article Number: 85813X
Series Proc. SPIE
Publisher Society of Photo-Optical Instrumentation Engineers
Publishing Place Washington, USA
Institute(s) Institute of Biological and Medical Imaging (IBMI)