Fig. 5
(a) SUV count (PET, left panel) and HU (CT, right panel) mean value distributions before and after thresholding to remove noisy voxels. Mean SUV counts were calculated for all voxels after removing voxels that were exactly at zero and after removing all voxels falling under a threshold. Mean HU values were calculated for all voxels after removing voxels at –1024. (referred to as zero thresholding in the figure), after thresholding calculated using the Otsu method and after applying the thresholding mask calculated using the PET modality of the same patient. (b) An example of CT binarization with Otsu thresholding. (c) An example of PET binarization with 95th percentile thresholding (same patient).
