Patent Number: 
Section: claims

1. A method for x-ray tomosynthesis or limited-angle CT of a subject or part of a subject, comprising:during imaging, moving a detector tray supporting a detector having a non-circular shape by rotating the detector tray, the detector comprising a plurality of detector cells, a greater density of the detector cells positioned at or near a center of rotation of the detector to provide a larger x-ray detection area near the center of rotation;shaping an x-ray beam to generally match the shape or part of the shape of the detector;moving or orienting the beam to track the motion of detector; andmoving an x-ray beam source with respect to the subject, while moving the beam to track the detector, to acquire at least two subject projections. 2. The method of claim 1, further comprising translating the detector tray. 3. A system for x-ray tomosynthesis or limited-angle CT of a subject or part of a subject, comprising:a gantry to rotate an x-ray detector of non-circular shape about an axis of rotation, the detector comprising a plurality of detector cells, a greater density of the detector cells positioned at or near a center of the axis of rotation to provide a larger x-ray detection area near the axis of rotation;a collimator to shape the x-ray beam to generally match the shape or part of the shape of the x-ray detector;a beam orientation mechanism to track the motion of the detector with the x-ray beam; andan x-ray beam source gantry to move an x-ray beam source with respect to the subject during tomosynthesis or limited-angle CT;wherein the axis of rotation corresponds with an x-ray beam central axis. 4. The system of claim 3, wherein the detector gantry translates within a plane or curved surface. 5. The system of claim 3, comprising means for unlimited rotation of the x-ray detector. 6. The system of claim 5, comprising means for power and signal transmission between the rotating detector and a non-rotating supporting assembly. 7. The system of claim 3, wherein the detector of non-circular shape is mounted on a rotatable tray, the rotatable tray mounted on a non-rotatable detector assembly that is moveable along at least two dimensions of a surface. 8. The system of claim 7, wherein the non-rotatable detector assembly comprises a slip-ring assembly for transmitting power to the rotatable detector tray while not limiting the number of detector rotations. 9. The system of claim 7, wherein the detector assembly comprises a wireless transmitter and receiver for transmission from the rotatable detector tray to the non-rotatable detector. 10. The system of claim 3, wherein the detector cells are arranged on a rectangular elongated matrix. 11. The system of claim 7, wherein the detector cells are arranged on a rectangular elongated matrix and wherein additional detector cells are provided at or near a center of rotation of the detector tray to provide for the larger x-ray detection area near the axis of rotation. 12. The system of claim 3, wherein the detector cells are arranged on a rectilinear elongated matrix and wherein additional detector cells are provided on one or several additional matrices. 13. The system of claim 3, further comprising means to dynamically and automatically track the location of a point in space. 14. The system of claim 13, wherein the point in space corresponds to a point on an interventional medical device selected from the group of a catheter, sheath, brachytherapy seed, probe, ablation element, and guide wire. 15. The system of claim 3, wherein the collimator is rotatable around the x-ray beam central axis. 16. The system of claim 3, comprising means for rotating the x-ray detector around the x-ray beam central axis in synchronicity with the collimator. 17. The system of claim 3, wherein the system is constructed and arranged for operation in a plurality of selectable imaging states including a non-tomosynthesis state.