1. A dual-source scanning-based radiation detecting apparatus comprising at least two radiation sources provided for emitting ionizing radiation; a plurality of direction sensitive line detectors arranged in an array; and a device for scanning said line detectors across an object to be examined, wherein the line detectors in said array are alternately pointing towards different ones of said radiation sources; and said device for scanning is arranged for keeping said line detectors aligned with said radiation sources during scanning to enable each of said line detectors to record a plurality of line images of said object.