Figure 2.
Example of histo-image data structures in DIRECT for a simulated 35-cm cylindrical phantom with hot spheres – both the reconstructed image and data (histo-images) have the same image dimensions and voxels of the same size with one-to-one correspondence between images and histo-images: (a) reconstructed image, (b) prompts (trues+scatter for tilt 0 and transverse angle 50°), (c) estimated scatters, and (d) sensitivity and attenuation factors. Corresponding slices of 3D image/histo-images are shown, each scaled to its maximum and cropped out of the circular FOV. Note that the attenuation factors are approximately constant along the view direction (along the LORs) while they change dramatically in the perpendicular direction (decreasing down to about 0.035 for the central LORs).