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c) Consequences of spatial heterogeneity
• Hypoxia can exist around all vessels in a tumor
– No relationship between hypoxia and tumor size!
• Oxygenation varies at the cellular (micron) level
• Imaging hypoxia always involves averaging over
very large numbers of cells.
– Hypoxic cells are likely to exist in all imaging voxels
– It will never be possible to deliver dose specifically to
hypoxic cells