Cone beam computed tomography volumetric imaging system

A method of performing radiographic examination of an object using a radiographic CT imaging system, the radiographic CT imaging system including a plurality of x-ray sources fixed to a ring each aimed at an imaging axis at a center of the ring and a corresponding ring of collimators about the imaging axis, the plurality of x-ray sources each having one collimator from the ring of collimators positioned adjacent thereto to collimate an x-ray beam emitted therefrom, and including a detector to revolve about the imaging axis to receive the collimated x-ray beams from the plurality of x-ray sources, the radiographic examination method comprising:

• positioning the object at the imaging axis and performing a first scan of the object including sequentially firing the plurality of x-ray sources at a first angular speed to acquire first CT projection data of a first field of view (FOV) of the object using the collimated x-ray beams emitted from the plurality of x-ray sources that impinge upon the revolving detector;
• identifying a region of interest within the first FOV;
• performing a second scan of the object by sequentially firing the plurality of x-ray sources at a second angular speed faster than the first angular speed to acquire second CT projection data of a second FOV of the object smaller than the first FOV including the region of interest within the first FOV, including more narrowly collimating the x-ray beams emitted by each of the plurality of x-ray sources using the collimator in the ring of collimators positioned adjacent thereto, revolving the detector at the second angular speed, and using the narrower x-ray beams from the plurality of x-ray sources that impinge upon only a portion of the detector;
• and
• outputting the first CT projection data and the second CT projection data from the detector.