The specific goal of this research is to develop a method of estimating the complete temperature field present in tumors and their surrounding tissues during clinical hyperthermia treatments. Since current clinical thermometry is invasive, temperatures are measured only at a limited number of points, and thus most temperatures in a tumor are unmeasured and unknown. This lack of knowledge is a fundamental problem in hyperthermia, which makes it impossible to perform complete therapy evaluations and to perform proper therapy control. This problem will remain until a method is developed which can predict the unknown tumor and normal tissue temperatures from the measured temperatures. Simple curve-fitting techniques will not suffice since they have no physical basis and are unable to accurately extrapolate data to predict unmeasured maxima or minima. To do this, a mathematical model of the physical processes in the treatment is needed. We propose to utilize such a model along with state and parameter estimation techniques to estimate the complete temperature field from knowledge of measured temperatures at a few locations. The approach uses optimization methods to minimize the difference between the measured temperatures and temperatures predicted by a bio-head transfer equation model of the heated region. Minimization is done by adjusting the model's blood perfusion parameters. The end result is predictions of both the complete temperature field in the region analyzed, and of the blood perfusion distribution and magnitude during the treatment. Our previous work on this problem has shown that the general approach is quite promising, and the proposed work will extend those results by: (1) improving the formulation of the bio-heat transfer equation, (2) improving the state and parameter estimation techniques, (3) extending and improving our simulation programs, (4) testing the results against extensive three dimensional in vitro and in vivo measurements in both normal and tumor tissues, and (5) applying the technique to clinical treatments. While the specific goal is to develop methods for predicting complete temperature fields, this study will also have the general result of improving both (1) knowledge of the temperature and blood perfusion distributions and fundamental heat transfer processes occurring in hyperthermia treatments, and (2) the ability to perform more realistic simulatings of hyperthermia. This will be important for all applications of treatment planning, control and evaluation.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA036428-08
Application #
3173991
Study Section
Radiation Study Section (RAD)
Project Start
1985-09-05
Project End
1992-08-30
Budget Start
1992-06-12
Budget End
1992-08-30
Support Year
8
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Arizona
Department
Type
Schools of Engineering
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85721
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Roemer, R B (1999) Conditions for equivalency of countercurrent vessel heat transfer formulations. J Biomech Eng 121:514-20
Mattingly, M; Roemer, R B; Devasia, S (1998) Optimal actuator placement for large scale systems: a reduced-order modelling approach. Int J Hyperthermia 14:331-45
Bailey, E A; Dutton, A W; Mattingly, M et al. (1998) A comparison of reduced-order modelling techniques for application in hyperthermia control and estimation. Int J Hyperthermia 14:135-56
Mattingly, M; Bailey, E A; Dutton, A W et al. (1998) Reduced-order modeling for hyperthermia: an extended balanced-realization-based approach. IEEE Trans Biomed Eng 45:1154-62
Huang, H W; Chen, Z P; Roemer, R B (1996) A counter current vascular network model of heat transfer in tissues. J Biomech Eng 118:120-9
Toglia, A; Kittelson, J M; Roemer, R B et al. (1996) Cerebral bloodflow in and around spontaneous malignant gliomas. Int J Hyperthermia 12:461-76
Anhalt, D P; Hynynen, K; Roemer, R B (1995) Patterns of changes of tumour temperatures during clinical hyperthermia: implications for treatment planning, evaluation and control. Int J Hyperthermia 11:425-36
Huang, H W; Chan, C L; Roemer, R B (1994) Analytical solutions of Pennes bio-heat transfer equation with a blood vessel. J Biomech Eng 116:208-12
Rawnsley, R J; Roemer, R B; Dutton, A W (1994) The simulation of discrete vessel effects in experimental hyperthermia. J Biomech Eng 116:256-62

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