Adjusting an X-ray parameter of an X-ray unit
An X-ray projection of a region of examination and an associated X-ray parameter are received via an interface, the X-ray projection including X-ray intensities in a first pixel set. The X-ray parameter relates to at least one X-ray voltage from an X-ray source. Scattered radiation intensity is determined in a second pixel set, the second pixel set being a subset of the first pixel set. A first calculation of first exposure parameters in the second pixel set then occurs, each of the first exposure parameters in a pixel of the second pixel set being based on the X-ray intensity in the pixel and the scattered radiation intensity in the pixel. Furthermore, a second calculation of a scalar second exposure parameter occurs based on the first exposure parameters and an adjustment of the X-ray parameter is performed by comparing the scalar second exposure parameter with a reference value.
1. A method for adjusting an X-ray parameter of an X-ray unit, the X-ray unit including an X-ray source and an X-ray detector, the method comprising:
receiving, via an interface, an X-ray projection of a region of interest and an associated X-ray parameter, the X-ray projection including X-ray intensities in a first pixel set and the X-ray parameter relating to at least one X-ray voltage from the X-ray source;
determining scattered radiation intensities in a second pixel set via a computing unit, the second pixel set being a subset of the first pixel set;
calculating, via the computing unit, first exposure parameters in the second pixel set, each of the first exposure parameters in a pixel of the second pixel set being respectively based on the X-ray intensity in the respective pixel and the scattered radiation intensity in the respective pixel;
calculating, via the computing unit, a scalar second exposure parameter based on the first exposure parameters; and
adjusting the X-ray parameter by comparing, via the computing unit, the scalar second exposure parameter with a reference value.
2. The method of claim 1 , wherein each of the first exposure parameters corresponds to a primary radiation intensity and wherein the respective primary radiation intensity in a respective pixel of the second pixel set is a difference between the X-ray intensity in the respective pixel and the scattered radiation intensity in the respective pixel.
3. The method of claim 1 , wherein each of the first exposure parameters in a respective pixel of the second pixel set corresponds to a ratio of the primary radiation intensity in the respective pixel to the scattered radiation intensity in the respective pixel.
4. The method of claim 1 , wherein the determining of the scalar second exposure parameter includes averaging the first exposure parameters of a third pixel set, the second pixel set including the third pixel set.
5. The method of claim 1 , wherein the scalar second exposure parameter is a quantile of a distribution of the first exposure parameters in a third pixel set, the second pixel set including the third pixel set.
6. The method of claim 1 , further comprising:
receiving an anatomical parameter of the region of interest,
wherein the determining of the scattered radiation intensities includes retrieving a reference dataset from a reference database, the reference dataset being selected using a comparison with the anatomical parameter and the X-ray parameter.
7. The method of claim 1 , further comprising:
receiving an anatomical parameter of the region of interest, wherein the determining of the scattered radiation intensity takes place by way of a Monte-Carlo simulation using the anatomical parameter and the X-ray parameter.
8. The method of claim 6 , wherein the anatomical parameter includes an extension of the region of interest with respect to a direction of projection of the X-ray projection.
9. The method of claim 6 , wherein the anatomical parameter includes a three-dimensional model of the region of interest and wherein the three-dimensional model is determined by way of the X-ray image dataset.
10. The method of claim 1 , wherein the determining takes place by measuring the scattered radiation intensities.
11. The method of claim 10 , wherein the measuring of the scattered radiation intensities takes place by introducing an X-ray-absorbing object in a beam path between the X-ray source and the region of interest,
wherein the X-ray-absorbing object absorbs at least 90% of the incident X-rays, and
wherein the scattered radiation intensities correspond to the X-ray intensities in the shadow pixels of the image of the X-ray-absorbing object in the X-ray projection.
12. A parameter-adjusting unit for adjusting an X-ray parameter of an X-ray unit, the X-ray unit including an X-ray source and an X-ray detector, parameter-adjusting unit comprising:
an interface, configured to receive an X-ray projection of a region of interest and an associated X-ray parameter, the X-ray projection including X-ray intensities in a first pixel set and the X-ray parameter relating to at least one X-ray voltage from the X-ray source; and
a computing unit, configured to
determine scattered radiation intensities in a second pixel set, the second pixel set being a subset of the first pixel set,
calculate first exposure parameters in the second pixel set, each of the respective first exposure parameters in a respective pixel of the second pixel set being based on the X-ray intensity in the respective pixel and the scattered radiation intensity in the respective pixel,
calculate a scalar second exposure parameter based on the first exposure parameters, and
adjust the X-ray parameter by comparing the scalar second exposure parameter with a reference value.
13. The parameter-adjusting unit of claim 12 , wherein each of the first exposure parameters corresponds to a primary radiation intensity and wherein the respective primary radiation intensity in a respective pixel of the second pixel set is a difference between the X-ray intensity in the respective pixel and the scattered radiation intensity in the respective pixel.
14. An X-ray unit configured to record X-ray projections of a region of interest, comprising the parameter-adjusting unit of claim 12 .
15. A non-transitory computer program product including a computer program, directly loadable into a memory unit of a parameter-adjusting unit, the computer program including program sections to carry out the method of claim 1 when the program sections are executed by the parameter-adjusting unit.
16. A non-transitory computer-readable storage medium including program sections, readable and executable by a parameter-adjusting unit, stored to carry out the method of claim 1 when the program sections are executed by the parameter-adjusting unit.
17. The method of claim 2 , wherein the determining of the scalar second exposure parameter includes averaging the first exposure parameters of a third pixel set, the second pixel set including the third pixel set.
18. The method of claim 3 , wherein the determining of the scalar second exposure parameter includes averaging the first exposure parameters of a third pixel set, the second pixel set including the third pixel set.
19. The method of claim 2 , wherein the scalar second exposure parameter is a quantile of a distribution of the first exposure parameters in a third pixel set, the second pixel set including the third pixel set.
20. The method of claim 3 , wherein the scalar second exposure parameter is a quantile of a distribution of the first exposure parameters in a third pixel set, the second pixel set including the third pixel set.
21. The method of claim 7 , wherein the anatomical parameter includes an extension of the region of interest with respect to a direction of projection of the X-ray projection.
22. The method of claim 7 , wherein the anatomical parameter includes a three-dimensional model of the region of interest and wherein the three-dimensional model is determined by way of the X-ray image dataset.
23. An X-ray unit configured to record X-ray projections of a region of interest, comprising the parameter-adjusting unit of claim 13 .
24. A non-transitory computer-readable storage medium including program sections, readable and executable by a parameter-adjusting unit, stored to carry out the method of claim 2 when the program sections are executed by the parameter-adjusting unit.