Method and device for calculating voxels defining a tube-of-response using a central-ray-filling algorithm

A reconstruction device for calculating voxels defining a tube-of-response (TOR) within a reconstruction space of a Positron Emission Tomography (PET) apparatus having a plurality of crystals, the voxels within the reconstruction space having a predetermined size, the reconstruction device comprising:

• a processing circuit configured to
• select a center on each of two crystals defining a line of response;
• determine intersected voxels within the reconstruction space that intersect a straight line connecting the centers of the two crystals;
• calculate neighboring voxels for each intersected voxel of the intersected voxels, based on an expansion direction and an expansion distance, the expansion distance being determined for each intersected voxel based on a position of the intersected voxel along the straight line, when lines connecting endpoints of the two crystals are not parallel to each other;
• merge the intersected voxels and the neighboring voxels to form a merged set of voxels;
• and
• delete duplicate voxels in the merged set of voxels to generate the voxels defining the TOR.