Fig. 5

Correlation between MPO2 and GPO2 in the tumor at various voxel sizes. At 50-µm voxel size (a), two outlier populations (highlighted by green and red dash ovals) were observed. The green oval indicates the voxels that were overestimated, MPO2 significantly greater than GPO2, and the red oval the voxels that were underestimated, MPO2 significantly lower than GPO2. The correlation and linear regression analysis for voxel sizes 100, 150, and 200 μm (see b–d) are better compared to the other voxel sizes (see a, e, f)