A mobile radiography apparatus has a moveable (e.g., wheeled) transport frame and an adjustable column mounted at the frame. A boom apparatus supported by the adjustable column can support an x-ray source assembly. Radiation or X-ray source assembly methods and/or apparatus embodiments can provide mobile radiography carts a capability to direct x-ray radiation towards a subject from one or a plurality of different source positions, where the X-ray source assembly includes a first x-ray power source and a second plurality of distributed x-ray sources disposed in a prescribed spatial relationship.