1. A computed tomography (CT) imaging system comprising: a radiation source including a collimating or a blocking device configured to generate both a narrow beam and a wide beam; a detector system configured to detect radiation from the radiation from the radiation source, wherein the detector system comprises a plurality of layers of detector arrays, and a filling material disposed between layers, wherein the filling material has measurable or known attenuation properties; and at least one processing circuit configured to: determine a scatter-to-primary ratio (SPR) of the wide beam based on the narrow beam; calculate a primary component of the wide beam based on the SPR to thereby separate the primary component from a scattered component of the wide beam; and construct an image of an object inside a patient using the primary component to thereby improve a contrast of the object.