Abstract: A multislice CT scanner for imaging a patient comprising: an X-ray source that generates a cone beam of X-rays radiated from a focal spot of the X-ray source wherein the X-ray source is moveable in a rotation plane so as to rotate the focal spot about an axial direction along which the patient is moved to position the patient in a field of view of the scanner; and a detector array comprising a plurality of rows of X-ray detectors that generate signals responsive to X-rays in the cone beam, which signals are used to generate an image of the patient; wherein the cone beam is asymmetric with respect to the rotation plane.

Abstract: A CT scanner for imaging an ROI of a patient comprising: an X-ray source and detector array that define an FOV of the scanner, a couch on which the patient is supported that moves the patient through the FOV; and a controller that: controls the X-rays source to image a portion of the patient's body that passes through the FOV prior to the ROI with X-rays at a first intensity; estimates an entry position of the couch for which the ROI is expected to enter the FOV from at least one feature in the prior portion image; determines an ROI imaging start position for the couch, responsive to the estimated entry position; and controls the X-ray source to illuminate the FOV with X-rays at a second intensity suitable for imaging the ROI when the couch reaches the ROI imaging start position to initiate imaging of the ROI.