Effective dual-energy x-ray attenuation measurement

A computed tomography system for measuring dual-energy X-ray attenuation data of an object under examination, the computed tomography system comprising

• a rotatable holder being rotatable around a rotation axis,
• an X-ray source comprising a first X-ray focus point and a second X-ray focus point, the X-ray source being mounted at the rotatable holder,
• an X-ray detection device comprising a plurality of detector elements,
• the detector elements being divided into a first group of first detector elements and a second group of second detector elements, wherein the first and the second detector elements exhibit different spectral sensitivities, and
• the X-ray detection device being mounted at the rotatable holder opposite to the X-ray source with respect to the rotation axis, and
• a control unit,
• which is coupled to the X-ray source and to the X-ray detection device and which is adapted for performing the following operation:
• adjusting the X-ray source such that it emits X-rays originating from the first X-ray focus point,
• acquiring first X-ray attenuation data separately with the first detector elements and with the second detector elements,
• moving the X-ray focus from the first X-ray focus point to the second X-ray focus point, and
• acquiring second X-ray attenuation data separately with the first detector elements and with the second detector elements,
• wherein the two X-ray focus points are spatially separated from each other such that a first beam path originating from the first X-ray focus point penetrates a certain voxel within the object and impinges on a first detector element and a second beam path originating from the second X-ray focus point penetrates the same voxel and impinges on a second detector element, and
• wherein the X-ray focus is moved in a discrete manner from the first X-ray focus point to the second X-ray focus point.

A computer-readable medium on which there is stored a computer program

• for measuring dual-energy X-ray attenuation data of an object under examination by means of a computed tomography system, the tomography system comprising
• a rotatable holder being rotatable around a rotation axis,
• an X-ray source comprising a first X-ray focus point and a second X-ray focus point, the X-ray source being mounted at the rotatable holder, and
• an X-ray detection device comprising a plurality of detector elements,
• the detector elements being divided into a first group of first detector elements and a second group of second detector elements, wherein the first and the second detector elements exhibit different spectral sensitivities, and
• the X-ray detection device being mounted at the rotatable holder opposite to the X-ray source with respect to the rotation axis,
• which computer program, when being executed by a processor, is adapted for performing the following operation:
• adjusting the X-ray source such that it emits X-rays originating from the first X-ray focus point,
• acquiring first X-ray attenuation data separately with the first detector elements and with the second detector elements,
• moving the X-ray focus from the first X-ray focus point to the second X-ray focus point, and
• acquiring second X-ray attenuation data separately with the first detector elements and with the second detector elements,
• wherein the two X-ray focus points are spatially separated from each other such that a first beam path originating from the first X-ray focus point penetrates a certain voxel within the object and impinges on a first detector element and a second beam path originating from the second X-ray focus point penetrates the same voxel and impinges on a second detector element, and
• wherein the X-ray focus is moved in a discrete manner from the first X-ray focus point to the second X-ray focus point.