Some embodiments are associated with an X-ray source 112 configured to generate X-rays directed toward an object 105, wherein the X-ray source is to: (i) generate a first energy X-ray pulse, (ii) switch to generate a second energy X-ray pulse, and (iii) switch back to generate another first energy X-ray pulse. A detector 120 may be associated with multiple image pixels, and the detector includes, for each pixel: an X-ray sensitive element to receive X-rays； a first storage element and associated switch to capture information associated with the first energy X-ray pulses； and a second storage element and associated switch to capture information associated with the second energy X-ray pulse. A controller 160 may synchronize the X-ray source and detector.
