Reconstruction of 3d image datasets from X-ray cone-beam data

Abstract

The invention is directed to a method for producing a 3D image dataset of an object (20) with an imaging system (1) having an X-ray source (4) for emitting photon rays in a cone beam and a detector (10) comprising a two-dimensional array of detector elements adapted for receiving photons emitted by the X-ray source, the method comprising: acquiring (100) a series of two-dimensional arrays of cone beam data from the detector (10) while the source (4) moves along a substantially planar trajectory (40) around the object to be imaged, the trajectory being described by a series of source points serially numbered by a counter parameter; and reconstructing a 3D image from the cone beam data by performing the following steps: A) differentiating the cone beam data with respect to the counter parameter (Lambada) of the source trajectory at fixed ray direction (Alpha) to produce a derivative of the cone beam data; B) filtering the derivative with a Hilbert-like filter to produce filtered cone beam data; C) either before step A), or after step B) multiplying the acquired cone beam data or the filtered cone beam data, respectively, with a redundancy weighting function; and D) back-projecting the cone beam data to compute a 3D image dataset.

Description

technical field [0001] The present invention generally relates to a method and imaging system capable of generating a three-dimensional (3D) image data set of an object. The imaging system includes an X-ray source that emits X-rays in a cone-shaped beam (commonly called a cone-beam) and includes a detector for acquiring a projected image of an object at a time (commonly called a cone-beam projection). A detector of a two-dimensional (2D) array of elements. More specifically, the present invention relates to a new method for reconstructing a three-dimensional image data set from cone beam data acquired by such an imaging system. Background technique [0002] In a fan beam computed tomography (CT) system, an X-ray source projects a fan beam that is collimated to lie within the xy plane of a Cartesian coordinate system called the imaging plane. A beam of X-rays passes through an object being imaged (such as a medical patient) and hits a one-dimensional array of radiation dete...

AI Technical Summary

Problems solved by technology

However, these systems have not been used to reconstruct 3D images because in such X-ray systems, the X-ray source will move along a planar polygon-based trajectory during one 3D scan

Unfortunately, there are no available reconstruction algorithms for cone beam projections obtained with non-circular trajectories

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