US 8,027,428 B2Granted

CT system and method for phase-contrast and absorption imaging

AssigneeSiemens Aktiengesellschaft

InventorEckhard Hempel

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Abstract

A CT system is disclosed for phase-contrast and absorption imaging with a plurality of emitter-detector systems. In at least one embodiment, there are at least two emitter-detector systems and the at least two emitter-detector systems have a different distance between radiation focus and detector and there is a computational element for calculating phase-contrast images on the basis of the solution to the intensity transport equation. Moreover, at least one embodiment of the invention relates to a method for phase-contrast and absorption imaging using such a CT system by comparing attenuation images recorded at different distances of a detector from a multiplicity of projection angles by solving the intensity transport equation and reconstruction or comparison of two tomographic and three-dimensional image data records, reconstructed from projections, which were recorded at different distances.

Claims13

Dependent claims

A CT system for phase-contrast and absorption imaging, comprising:

a gantry, rotatable about a system axis;
at least two emitter-detector systems, attached to the gantry with an angular offset to scan a measurement field, a specified distance existing between a radiation focus in a respective emitter and a respective detector with its detector elements in each of the at least two emitter-detector systems, measurement beams being defined by a geometric connection between respective a radiation focus and detector element, and at least two of the at least two emitter-detector systems including different distances between respective radiation focus and detectors;
and
a computational and control unit configured to control the CT system, the computational and control unit including a computational element configured to solve a transport intensity equation on the basis of at least two projections recorded at the same projection angle at different distances, which outputs phase and intensity values of the measurement beams for a multiplicity of projection angles, and including a computational element configured to reconstruct tomographic image data from at least one of the calculated phase values and intensity values.

1 more element

A method for phase-contrast and absorption imaging with a dual-emitter- or multi-emitter-detector CT system, wherein a gantry, on which at least two emitter-detector systems are attached with an angular offset, is configured to rotate about a system axis to scan an examination object in a measurement field and at least two attenuation images are recorded for each projection angle at a multiplicity of projection angles, the method comprising:

using the at least two attenuation images per projection angle, recorded at different distances from the emitter, to determine intensity gradients in a measurement beam direction;
calculating a phase value per measurement beam by solving a transport intensity equation;
and
calculating a tomography image from the calculated phase values from a multiplicity of projection angles.

1 more element

Dependencies are inferred from the claim text.