Patent ID: 6845144
Filing Date: 2005-01-18
Classification: A61B,G06T,Y10S

Abstract:
1. A three dimensional back projection method comprising the steps of: defining a direction perpendicular to at least one of a rotating plane of an X-ray tube, a multidetector, and a direction of linear displacement of a helical scan as a z-axis, a direction of a center axis of an X-ray transmission beam at view=0° as a y-axis, and a direction normal to both the z- and y-axis as an x-axis; defining a first xz projection plane as the projection plane that passes through a center of rotation in a view angle range that is approximately −45°≦view<45° and also includes the periphery thereof or in a view angle range that is approximately 135°≦view<225° and also includes the periphery thereof; projecting projection data D defining a second yz projection plane as the projection plane that passes through the center of rotation in a view angle range that is approximately 45°≦view<135° and also includes the periphery thereof or in a view angle range that is approximately 225°≦view<315° and also includes the periphery thereof; projecting the data D adding for each corresponding pixel the back projection pixel data D