Dual energy X-ray imaging.  Two is better than one.
D015901:Angiography, Digital Subtraction; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging; D003287:Contrast Media; D006073:Gout / Q000000981:diagnostic imaging; D006801:Humans; D007669:Kidney Calculi / Q000737:chemistry / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media