1. A method for an imaging system, comprising: performing, with a scanner, a scan of a subject to acquire emission data; initiating reconstruction of the emission data using an image reconstruction processor; executing instructions stored in a memory that cause a processor to calculate an amount of external scatter contamination in the emission data, wherein external scatter contamination is calculated based on an estimated emission activity originating from anatomies outside a field-of-view (FOV) of the scanner prior to the memory instructing the processor to calculate scatter originating within the FOV; wherein the anatomies are identified based on an image segmentation analysis performed on an image generated in the imaging system; executing instructions stored in the memory to calculate a total scatter by summing a total FOV scatter and a total OOF scatter; applying the total scatter to the emission data to correct the emission data; completing reconstruction of the emission data acquired by the processor using the image reconstruction processor, wherein the reconstructed emission data is corrected emission data; and displaying reconstructed emission data; wherein the image generated in the imaging system is acquired from the imaging system prior to acquiring the emission data.