Methods and apparatus for collimation of detectors in an imaging system are provided. One an imaging system includes a radiation source configured to project radiation from a focal spot onto an object and a plurality of radiation detectors disposed around at least a portion of the object. The plurality of radiation detectors detect received radiation along a path projected from the focal spot to the plurality of detectors. The imaging system also includes a plurality of collimators positioned between the object and the plurality of detectors, wherein the collimators have a tapered configuration.