1. A radioemission imaging system comprising: a radioemission imaging data acquisition system configured to acquire radioemission imaging data in a field of view (FOV); an electronic data processing device programmed to reconstruct the radioemission imaging data by operations including: identifying a background portion of the radioemission imaging data corresponding to a background region of the FOV that is outside of an object disposed in the FOV; adjusting an outside-FOV activity estimate for at least one spatial region outside of the FOV to optimize a simulated scatter distribution for the combination of the radioemission imaging data and the outside-FOV activity estimate; and reconstructing a scatter-corrected image of the object in the FOV using the optimized simulated scatter distribution.