Patent ID: 6324246
Filing Date: 2001-11-27
Classification: A61B,Y10S

Abstract:
A method for reconstructing images of an object in a variable-angle helical-scan CT scanner, said scanner including an X-ray tube mounted for rotation about a rotation axis, a detector array having one or more rows of detector elements that generate signals responsive to X-rays incident thereon, and a surface, translatable along a translation axis, on which surface the object is placed, said method comprising:(a) angling the translation axis and the rotation axis at an acute angle relative to one another;(b) rotating the X-ray tube about the rotation axis while translating the surface along the translation axis through a plane of rotation of the tube, whereby the X-ray tube describes a helical path relative to the object;(c) acquiring first, second and optionally additional views at the same effective rotational angle about the axis of rotation, said views comprising X-ray attenuation data received from elements of the array;(d) producing a planar corrected view at a given image slice position by interpolation of the data in at said first, second and optionally additional views, wherein the data is generated by non-corresponding elements in different views; and(e) repeating (a)-(d) at a plurality of rotational angles of the X-ray tube, for the given slice position; and(f) reconstructing an image of the slice from planar corrected views taken over a given range of view angles;wherein images taken at angle separated by integral multiples of 180 or 360 degrees, depending on the range of view angles, are defined as being taken at the same effective angle.