SYSTEM, METHODS, AND DEVICES FOR CALCULATING HYPOXIC FRACTION AND EQUILIBRATION RATE OF SMALL MOLECULAR WEIGHT TRACERS USING DYNAMIC IMAGING

摘要

Uptake of hypoxia-sensitive PET tracers is dependent on tissue transport properties, specifically, distribution volume. Variability in tissue transport properties reduces the sensitivity of static PET imaging to hypoxia. When tissue transport (v_d) effects are substantial, correlations between the two methods of determining hypoxic fractions are greatly reduced—that is, trapping rates k₃ are only modestly correlated with tumour-to-blood ratio (TBR). In other words, the usefulness of dynamic- and static-PET based hypoxia surrogates, trapping rate k₃ and TBR, in determining hypoxic fractions is reduced in regions where diffusive equilibrium is achieved slowly. A process is provided for quantifying hypoxic fractions using a novel biomarker for hypoxia, hypoxia-sensitive tracer binding rate k_b, based on PET imaging data. The same formalism can be applied to model the kinetics of non-binding CT and MT contrast agents, giving histopathological information about the imaged tissue.