X-ray detector system 18 with improved spatial resolution for a computed tomography systems is provided. Detector system 18 may include pairs of first and second detector arrays 50 and 52, with each array containing detector elements of a different design. In one embodiment, the first array 50 may comprise a first, relatively thin and continuous (i.e., monolithic) scintillation layer 70 with an array of individual diodes 74 positioned to receive light generated within the scintillation layer 70. The second array may comprise a second, relatively thick scintillation layer 80 formed of separate scintillator elements 82. An array of diodes 86 may be positioned to receive radiation from the scintillation layer 80 such that each diode element 82 is aligned to primarily receive radiation from one scintillator element 82 in the layer 80. The structural arrangements of the detector system may also be adapted for applications involving direct conversion of x-ray energy.