Access Type

Open Access Dissertation

Date of Award

1-1-1997

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Cancer Biology

First Advisor

Dr. Jeffrey L. Evelhoch

Abstract

The ultimate goal of this dissertation is to describe the optimization and implementation of an NMR indicator uptake technique which can non-invasively and repeatedly measure tissue perfusion. Chapter II concerns itself with the method optimization of the NMR approaches to measuring tissue perfusion. Since the primary goal of this dissertation research is to obtain absolute perfusion measures, and the AIF is required for this, Chapter II discusses the development of the apparatus and NMR method with which one can extract an apparent AIF from individual rats - a method which will not necessarily result in the animal's immediate death. As a further extension of this goal, research was performed to determine the feasibility of eliminating the need for individual AIF measurement by constructing a common AIF from a small set of animals, and then of using this derived common AIF for all subsequent animals within a study. Chapter II also describes results of computer simulations performed to assess the impact which tissue perfusional heterogeneity, indicator SIN within the tissue sample, and variations in the AIF have on determining absolute perfusion with the two methods of data analysis used with the NMR uptake approach. In Chapter III, a modified uptake approach is introduced (developed as a consequence of the results of the research performed in Chapter II) which uses a common AIF and a bolus indicator dose, as well as optimized data analysis. This modified uptake approach is tested against a commonly used method (which does not require knowledge of an AIF in measuring absolute tissue perfusion. The comparison was done by designing apparatus and developing techniques which allowed the simultaneous performance of whole-volume average perfusion measurements of a rat tumor model with both the modified NMR uptake method and the commonly used microsphere approach. Finally, Chapter IV summarizes the dissertation experiments performed, and briefly comments on the significance of this research.

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