METHOD FOR LOCAL ADJUSTMENT OF REGULARIZATION PARAMETERS FOR IMAGE QUALITY OPTIMIZATION IN FULLY 3D ITERATIVE CT RECONSTRUCTION

摘要

A method and related apparatus (116) for iterative reconstruction of a volume. A regularization parameter (β) of an iterative update function is spatially adapted and normalized in respect to a region of interest ROI in the volume. The method allows achieving essentially uniform noise distribution across the reconstructed volume.

主权项

1. A CT image processing method, including the following steps of:
receiving projection data acquired of a volume along a scan direction, one or more image points of said volume reconstructable, in an iterative reconstruction operation, from at least a part of said projection data; as a function of a position in a volume reconstructed in a previous iteration or otherwise reconstructed, computing a regularization parameter for an image point at said position for a next iteration in said iterative reconstruction operation; as a function of a scan position along the scan direction, normalizing the regularization parameter relative to a region of interest, ROI, of an object in a plane across the volume at said scan position, the ROI defined by a mask m, wherein the normalizing is via a mean or a weighted mean of the regularization parameter; when iteratively reconstructing, in said next iteration, said image point from the projection data, applying said normalized regularization parameter.