A computed tomography (CT) detector array (120) includes a monolithic scintillator (124). The monolithic scintillator includes at least a first scintillator region (202), a second scintillator region (206), and an optically reflective barrier (210) therebetween. The detector array is configured to detect X-ray radiation traversing an examination region and impinging the monolithic scintillator and generate first projection data indicative of an energy of x-ray radiation absorbed by the first scintillator region and second projection data indicative of an energy of x-ray radiation traversing the first scintillator and absorbed by the second scintillator region.