Koninklijke Philips Corporation N.V.

U.S. Philips Corporation

Per-Erik Danielsson

Henrik Turbell

The invention relates to a computed tomography method in which a conical radiation beam traverses an examination zone during a helical relative motion between the radiation beam and the examination zone. The reconstruction is performed by means of filtered backprojection, the filtering operations involving measured values resulting from different projections of voxels from at least approximately the same surface within the examination zone.

Computed tomography method involving a helical relative motion

The invention relates to a computed tomography method in which the summing operation required for filtered backprojection is performed in two steps, filtering being performed only after the first summing step. This method is preferably performed for the points on a surface, which is defined by parallel rays, which are situated in parallel planes and link oppositely situated segments of the helix.

The invention relates to a CT method which involves helical scanning of an examination zone by means of a cone beam. Measuring data for the three-dimensional tomographic imaging of objects of arbitrary length are now acquired completely and without redundancy. The reconstruction requires only a one-dimensional filtering operation. Particularly simple processing steps are enabled by a rebinning operation during which fan beams which are situated in planes extending parallel to one another and to the axis of rotation are combined.

Computer tomagraphy method with helicoidal scanning of an examination area

Complete helical cone-beam scanning and non-redundant data acquisition are obtained for three-dimensional tomographic imaging of arbitrary long objects. The minimum sized two-dimensional detector window is bounded by two consecutive turns of the helix. The ray source exposes all object points during a rotation of exactly 180 degrees when seen from the points themselves. Only one-dimensional filtering is employed in the reconstruction. Rebinning to parallel beams, as seen along the axis of rotation, allows for especially simple procedures without any need for pre-weighting or magnification factors. As a special case, the invention is applicable to helical fan-beam scanning with one-dimensional detector arrays.

Growing community of inventors

Linköping, Sweden

Per-Erik Danielsson