Theoretical Study of Amplitude Modulation Application during Radio Frequency Electrocoagulation

Nauka i Obrazovanie. 2015;0(5):178-189 DOI 10.7463/0515.0766262

 

Journal Homepage

Journal Title: Nauka i Obrazovanie

ISSN: 1994-0408 (Online)

Publisher: MGTU im. N.È. Baumana

Society/Institution: MGTU im. N.È. Baumana

LCC Subject Category: Technology: Electrical engineering. Electronics. Nuclear engineering: Electronics: Computer engineering. Computer hardware | Technology: Engineering (General). Civil engineering (General): Mechanics of engineering. Applied mechanics

Country of publisher: Russian Federation

Language of fulltext: Russian

Full-text formats available: PDF

 

AUTHORS

V. A. Karpuhin (Bauman Moscow State Technical University)
V. A. Zamiatina (Bauman Moscow State Technical University)

EDITORIAL INFORMATION

Peer review

Editorial Board

Instructions for authors

Time From Submission to Publication: 4 weeks

 

Abstract | Full Text

<p>This article concerns the investigation results of influence of the amplitude-modulated acting signal parameters on the thermoelectric characteristics of biological tissues for a specified geometry of the working electrode section during RF mono-polar electrocoagulation. The geometric model ‘electrode - a biological tissue’ was suggested to study the distribution of power and temperature fields in biological tissue during mono-polar coagulation. The model of biological tissue is represented as a cylinder and the needle electrode is an ellipsoid immersed in the biological tissue. The heat and quasi-electrostatics equations are used as a mathematical model. These equations are solved in Comsol Multiphysics environment.</p><p>As a result, we have got the following findings: the technique of calculating parameters of the PAM acting signal which has a fixed carrier frequency for the needle electrode of a specified geometry and the immersion depth in biological tissues is suggested. Parameters of PAM signal are determined for this electrode geometry. These parameters provide a 60 ... 80°C heating range of biological tissues near the working part of the tool for different amplitudes of acting signal during RF coagulation. It has been found out that both the temperature and the relaxation frequency of biological tissue depend on exposure time for the needle electrode of a specified geometry and immersion depth of the working part of tool into biological tissue.</p><p>It is shown that the relaxation frequency of the biological tissue, subjected to the radiofrequency pulses, linearly depends on its heating temperature and can be used as a numerical criterion for maintaining the specified temperature conditions. It is found that the relaxation frequency of the biological tissue depends on the contact area of the tool working part and biological tissues. To reduce this dependence it is necessary to provide automatic current control of the output action.</p>