An imaging system (100) includes a radiation source (108) that emits radiation that traverses an examination region and imageable drug eluting beads in tissue of interest located therein, a spectral detector array (110) detects radiation traversing the examination region and generates a signal indicative thereof, spectral processing circuitry (117) that spectrally resolves the signal based on a plurality of thresholds (122), and a reconstructor (128) that generates spectral volumetric image data corresponding the imageable drug eluting beads based on the spectrally resolved signal.