An imaging system comprises a digital radiation detector and radiation source. A detector transport moves the detector along at least a portion of a first curved path and a radiation moves the source along at least a portion of a second curved source path. The detector is configured to travel at least a portion of the first curved path, and the source is configured to travel at least a portion of the second curved path. The detector is configured to obtain a plurality of 2D projection images over a range of scan angles for reconstructing a 3D volume image using the plurality 2D projection images.