Design and thermal modeling of a non-invasive probe for measuring perfusion by thermodiffusion
Name
153263945-MIT.pdf
Description
Full printable version
Size
7.7 MB
Format
Adobe PDF
Checksum (MD5)
c355e0f3a8d27d174c0c2155f720cef7
Author(s)
Charles, Steven Knight
Advisor(s)
H. Frederick Bowman.
Date Issued
2004
Publisher
Massachusetts Institute of Technology
Abstract
This research 1) explores the feasibility of developing a non-invasive probe to precisely quantify microcirculatory blood flow (tissue perfusion), in real time and in absolute units, and 2) presents designs and models of such a probe, along with an evaluation of various design-model combinations. Bowman et al. have developed an invasive thermodiffusion probe that measures tissue perfusion accurately, continuously, and in real time. This method employs a self-heated thermistor placed in perfused tissue. From a knowledge of the power required to heat the thermistor probe to a given temperature, perfusion can be calculated using an analytical or numerical model. Using Bowman's thermodiffusion probe (designed for invasive use) in a non-invasive manner, a perfusion study was performed. The data clearly show the promise of a non-invasive thermodiffusion perfusion probe (designed for non-invasive use), and the design of such a probe was pursued by adapting the invasive technology for a non-invasive probe. Because perfusion is not actually measured but calculated from measured quantities by a model of the probe and perfused tissue, the design of the non-invasive probe occurred hand-in-hand with the development of analytical models.
(cont.) The results of the clinical study are presented, as well as two designs together with possible one-dimensional analytical models. Using a finite-difference model of the two probe designs and the underlying perfused tissue, the errors that result from approximating these designs as one-dimensional models have been determined. It is shown that modeling a thin, disk-shaped thermistor probe as a hemisphere of appropriate radius can result in an error in calculated perfusion which is small enough for clinical use.
Description
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
Includes bibliographical references (p. 89-91).
Subjects
Mechanical Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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