1. A method, comprising the steps of: a list-based reconstruction technique generating first portion tomographic data responsive to a first portion of a plurality of positron annihilation events detected during a positron emission tomography scan; generating an image indicative of the first portion tomographic data; a list-based reconstruction technique generating composite tomographic data responsive to the first portion tomographic data and a second portion of the plurality of positron annihilation events; and generating an image indicative of the composite tomographic data.