Optical, thermal, and electrical monitoring of radio-frequency tissue modification

Timmy Floume; Richard R. A. Syms; Ara W. Darzi; George B. Hanna

doi:10.1117/1.3323089

1 January 2010 Optical, thermal, and electrical monitoring of radio-frequency tissue modification

Timmy Floume, Richard R. A. Syms, Ara W. Darzi, George B. Hanna

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Journal of Biomedical Optics, Vol. 15, Issue 1, 018003 (January 2010). https://doi.org/10.1117/1.3323089

Abstract

Radio-frequency (rf) tissue fusion involves the sealing of tissue between two electrodes delivering rf currents. Applications include small bowel fusion following anastomosis. The mechanism of adhesion is poorly understood, but one hypothesis is that rf modification is correlated to thermal damage and dehydration. A multimodal monitoring system capable of acquiring tissue temperature, electrical impedance, and optical transmittance at 1325-nm wavelength during rf delivery by a modified Ligasure^TM fusion tool is presented. Measurements carried out on single layers of ex vivo porcine small bowel tissue heated at ≈500-kHz frequency are correlated with observation of water evaporation and histological studies on full seals. It is shown that the induced current generates a rapid quasilinear rise of temperature until the boiling point of water, that changes in tissue transmittance occur before impedance control is possible, and that a decrease in transmission occurs at typical denaturation temperatures. Experimental results are compared with a biophysical model for tissue temperature and a rate equation model for thermal damage.

©(2010) Society of Photo-Optical Instrumentation Engineers (SPIE)

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Timmy Floume, Richard R. A. Syms, Ara W. Darzi, and George B. Hanna "Optical, thermal, and electrical monitoring of radio-frequency tissue modification," Journal of Biomedical Optics 15(1), 018003 (1 January 2010). https://doi.org/10.1117/1.3323089

Published: 1 January 2010

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