irections, </span><span style=' font-family: monospace;'>FOVtr</span><span> the FOV size in transaxial direction (length of one side of the square), </span><span style=' font-family: monospace;'>axial_fov</span><span> the size of the FOV in axial direction, </span><span style=' font-family: monospace;'>subsets</span><span> is an optional number of subsets (can be omitted), </span><span style=' font-family: monospace;'>implementation</span><span> the optional implementation that should be used (4 is default,