Basic Clinical Radiobiology 2017

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