Method and apparatus for cone beam imaging

摘要

The method involves applying a conical beam of energy from a cone beam source onto a portion of an object. A source scanning trajectory is defined as the path traversed by the source. The object is scanned using the source positioned relative to an area detector with both the source and detector movably positioned relative to the object. The source scanning trajectory is specified as a spiral path with several stages spaced on a predefined geometric surface surrounding the field of view such that each plane passing through the field of view intersects the area detector along a line segment `L' that extends towards top and bottom edges of the area detector. The area detector includes several detector elements arranged in the form of matrix. The conical beam projection data are acquired by the detector elements by scanning at several locations along the source scanning trajectory. Then, radon derivative data are calculated by processing line integral values from cone beam projection data in adjacent detector line segments (L1,L2) that are parallel to the line segment (L) and translated in an orthogonal direction by an amount less than or equal to the spacing between the detector elements. The image of the object is reconstructed using radon derivative data.