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Proceedings Paper

Evaluation of a fuzzy logic controller for laser thermal therapy
Author(s): Vanessa Choy; Alireza Sadeghian; Michael D. Sherar; William Mark Whelan
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Paper Abstract

Laser thermal therapy (LTT) is a minimally invasive surgical technique used to destroy solid tumors while minimizing damage to adjacent normal tissues. Optical energy, delivered through fibers implanted into the target volume, raises tissue temperatures above 60 degree(s)C resulting in coagulative necrosis (thermal damage). Thermal damage volumes, however, can be irregular and unpredictable, resulting from dynamic changes in the tissue properties during treatment. A closed-loop feedback fuzzy logic controller for LTT was developed with the tissue treated as a black-box system. Preliminary testing was conducted for simulated LTT with a single spherically emitting source fiber at the center of 5 mm and 10 mm diameter target tissues. Dynamic changes in blood perfusion and tissue optical properties due to heating were incorporated into the LTT simulator. Input laser power was modulated to control the temperature field in an attempt to reach target temperatures at the source (90 degree(s)C to avoid tissue charring) and at the target boundary (55 degree(s)C). In all simulations, thermal damage based on Arrhenius formulation ((Omega) equals 1) was reached at the target boundary. The controller also responded efficiently to unexpected, rapid temperature changes.

Paper Details

Date Published: 27 June 2002
PDF: 10 pages
Proc. SPIE 4617, Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical, (27 June 2002); doi: 10.1117/12.472510
Show Author Affiliations
Vanessa Choy, Univ. of Toronto (Canada)
Alireza Sadeghian, Ryerson Univ. (Canada)
Michael D. Sherar, Univ. of Toronto and Princess Margaret Hospital/Univ. Health Network (Canada)
William Mark Whelan, Univ. of Toronto and Ryerson Univ. (Canada)

Published in SPIE Proceedings Vol. 4617:
Laser Tissue Interaction XIII: Photochemical, Photothermal, and Photomechanical
Steven L. Jacques; Donald Dean Duncan; Donald Dean Duncan; Sean J. Kirkpatrick; Sean J. Kirkpatrick; Andres Kriete; Andres Kriete, Editor(s)

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