METHOD AND SYSTEM FOR MASKING CONE BEAM PROJECTION DATA GENERATED FROM EITHER A REGION OF INTEREST HELICAL SCAN OR A HELICAL SCAN

The present invention discloses a method and system for performing three-dimensional computerized tomography imaging of a region of interest of an object. In the present invention, a scanning trajectory is provided about the object. The scanning trajectory includes a first scanning circle, a second scanning circle, and a helical scanning path connecting the first scanning circle and the second scanning circle. The scanning trajectory is then sampled with a plurality of cone beam source positions. Cone beam energy is emitted along the scanning trajectory from each of the plurality of cone beam source positions towards a portion of the object. Cone beam energy passing through the object is acquired on a detector as cone beam projection data. The cone beam projection data is then masked with a plurality of masks. Each of the masks remove cone beam projection data that is outside the region of interest of the object and retain cone beam projection data that is within the region of interest of the object. An image of the region of interest of the object is reconstructed from the masked cone beam projection data.