An imaging system includes radiation source (106) that emits radiation that traverses an examination region and a portion of a subject therein and a detector array (114) that detects radiation that traverses the examination region and the portion of the subject therein and generates a signal indicative thereof. A volume scan parameter recommender (120) recommends at least one spectral scan parameter value for a volume scan of the portion of the subject based on a spectral decomposition of first and second 2D projections acquired by the radiation source and detector array. The first and second 2D projections have different spectral characteristics. A console (122) employs the recommended at least one spectral scan parameter value to perform the volume scan of the portion of the subject.
