1. A method for reconstructing a radioactive emission image of an overall volume having first and second volumetric regions, each volumetric region having respectively independent dynamic characteristics, the method comprising: a) obtaining radioactive emissions from the overall volume, including said volumetric regions; b) reconstructing an initial radioactive emission image of said volumetric region according to said radioactive emissions; c) segmenting said initial radioactive emission image to delineate said first and second volumetric regions; and d) reconstructing said first and second volumetric regions according to said respectively independent dynamic characteristics.