An imaging system includes storage (12) for storing radionuclide imaging data including quantitative radiation detection event energy values, the radionuclide imaging data having been acquired of a subject by a radionuclide imaging device (10); an energy window selection module (20) selecting an energy window and a data filtering module (14) configured to filter the stored radionuclide imaging data respective to the stored quantitative radiation detection event energy values using the selected energy window to generate a filtered radionuclide imaging data set; and a reconstruction module (30) configured to reconstruct the filtered radionuclide imaging data set to generate a reconstructed image of the subject.