A system includes a detector and a processing unit. The detector includes multiple pixels configured to detect computed tomography (CT) events and nuclear medicine (NM) imaging events. The CT events correspond to X-rays emitted from a X-ray source through an object to be imaged, and the NM imaging events correspond to gamma rays emitted from a radiopharmaceutical that has been administered to the object. The detector is configured for photon counting detection of the CT events and the NM imaging events. The processing unit includes at least one processor and at least one memory comprising a tangible and non-transitory computer readable storage medium. The processing unit is configured to, based on corresponding energy levels of the CT events and the NM imaging events, identify CT information corresponding to the CT events and identify NM information corresponding to the NM imaging events.
