Topogram from a spiral reconstruction
View Patent ↗A computed tomography system is disclosed, along with a method and computer program product. An embodiment uses such a spiral acquisition to reconstruct a spatial three-dimensional image of the examination region. The method also includes establishing a topogram of the examination region by parallel projection of the image along a projection direction. An embodiment of the invention allows distortion-free acquisition of a topogram, as a reconstructed spatial three-dimensional image can simply be projected in a parallel manner along a projection direction. An embodiment also allows multiple topograms to be established easily with just one acquisition, in that the reconstructed image of the examination region is projected in a parallel manner along different directions. An embodiment of the invention also allows particularly fast acquisition of a topogram, in particular in the clinical environment, as the rotating part of the gantry does not have to be stopped for the spiral acquisition.
1. A method for establishing a topogram, based on a spiral acquisition of an examination region using a computed tomography system, the method comprising:
reconstructing a spatial three-dimensional image of the examination region using the spiral acquisition;
establishing a first topogram of the examination region by a parallel projection of the spatial three-dimensional image along a first projection direction;
computing an envelope of the examination region by segmenting the examination region in the spatial three-dimensional image; and
determining scattering parameters based on the computed envelope of the segmented examination region.
2. The method of claim 1 , further comprising:
establishing at least one second topogram of the examination region by a parallel projection of the spatial three-dimensional image along at least one second projection direction.
3. The method of claim 2 , further comprising:
determining acquisition parameters for a further acquisition of the examination region using at least one of the first topogram and the second topogram.
4. The method of claim 3 , wherein the acquisition parameters are intensity values for x-ray radiation for dose modulation for the further acquisition, the method further including:
determining the intensity values using at least the first topogram and the second topogram.
5. The method of claim 1 , further comprising:
determining acquisition parameters for a further acquisition of the examination region using at least the first topogram.
6. The method of claim 5 , wherein the acquisition parameters are intensity values for x-ray radiation for dose modulation for the further acquisition, and the method further includes
determining, the intensity values using at least the first topogram.
7. The method of claim 1 , further comprising:
applying a spiral acquisition with a dose smaller than 200 μSv during the spiral acquisition.
8. A non-transitory computer-readable storage medium including program code segments that, when executed, cause a computer to execute the method of claim.
9. A computed tomography system for establishing a topogram, the computed tomography system comprising:
an acquisition unit, including an x-ray source and an x-ray detector, designed for a spiral acquisition of an examination region;
a reconstruction unit, configured to reconstruct a spatial three-dimensional image of the examination region using the spiral acquisition;
an image processing unit, configured to
establish a first topogram of the examination region by a parallel projection of the spatial three-dimensional image along a first projection direction, and
compute an envelope of the examination region by segmenting the examination region in the spatial three-dimensional image; and
a determination unit, configured to determine scattering parameters based on the computed envelope of the segmented examination region.
10. The computed tomography system of claim 9 , wherein the image processing unit is further configured to establish at least one second topogram of the examination region by a parallel projection of the spatial three-dimensional image along at least one second projection direction.
11. The computed tomography system of claim 10 , further comprising:
a determination unit, configured to determine acquisition parameters for a further acquisition of the examination region using at least one of the first topogram and the second topogram.
12. The computed tomography system of claim 9 , further comprising:
a determination unit, configured to determine acquisition parameters for a further acquisition of the examination region using at least the first topogram.
13. The computed tomography system of claim 9 , wherein the acquisition unit further includes a second x-ray source and a second x-ray detector.
14. A computed tomography system for establishing a topogram, the computed tomography system comprising:
an acquisition unit, including an x-ray source and an x-ray detector, designed for a spiral acquisition of an examination region;
a reconstruction unit, configured to reconstruct a spatial three-dimensional image of the examination region using the spiral acquisition;
an image processing unit, configured to establish a first topogram of the examination region by a parallel projection of the image along a first projection direction; and
a computer, into which the program code segments included in the non-transitory computer-readable storage medium of claim 8 are loadable.