Out-of-field scatter estimation in 3D whole body PET

Many implementations of model based scatter correction (MBSC) are based on the single scatter simulation (SSS) formulation within the scan field-of-view (FOV). A fully 3D approach that models both the axial and trans-axial scatter components can accurately model scatter from hot regions in neighboring slices and outside the scan FOV resulting in greater quantitative accuracy. Herein we discuss how to incorporate the estimation of out-of-field scatter in fully 3D MBSC.