Method for scanogram scans in photon-counting computed tomography
View Patent ↗A computed tomography (CT) imaging apparatus includes an X-ray source to emit X-rays; a plurality of photon-counting detectors (PCDs) arranged in a circular ring between the X-ray source and a CT detector; and processing circuitry to cause the X-ray source and the CT detector to perform a helical scan of an object to obtain projection data; extract, from the obtained projection data, a plurality of sets of projection data corresponding to a plurality of X-ray tube positions of the helical scan; and combine the plurality of sets of extracted projection data to obtain a scanogram.
1. A computed tomography (CT) imaging apparatus, comprising:
an X-ray source configured to emit X-rays;
a plurality of photon-counting detectors (PCDs) arranged in a circular ring between the X-ray source and a CT detector; and
processing circuitry configured to
cause the X-ray source and the CT detector to perform a helical scan of an object to obtain projection data;
extract, from the obtained projection data, a plurality of sets of projection data corresponding to a plurality of X-ray tube positions of the helical scan; and
combine the plurality of sets of extracted projection data to obtain a scanogram.
2. The apparatus according to claim 1 , wherein the processing circuitry is further configured to cause the helical scan to be performed using a dose lower than a dose used for a helical scan performed to obtain a CT image of the object.
3. The apparatus according to claim 1 , wherein the processing circuitry is further configured to extract the plurality of sets of projection data at the plurality of X-ray tube positions to minimize effects of shadows caused by the PCDs.
4. The apparatus of claim 1 , wherein the X-ray source includes two X-ray emitters that are spatially and spectrally distinct.
5. The apparatus of claim 1 , wherein the X-ray source is configured to perform kV-switching and modulation.
6. A method to obtain a scanogram for a hybrid scanner that includes a ring of sparse, fixed photon-counting detectors (PCDs) and an X-ray source and a CT detector that rotate together, the method comprising:
causing the X-ray source and the CT detector to perform a helical scan of an object to obtain projection data;
extracting, from the obtained projection data, a plurality of sets of projection data corresponding to a plurality of X-ray tube positions of the helical scan; and
combining the plurality of sets of extracted projection data to obtain the scanogram.
7. The method according to claim 6 , wherein the step of performing the helical scan further comprises performing a helical scan using a dose lower than a dose used for a helical scan performed to obtain a CT image of the object.
8. The method according to claim 6 , wherein the combining step further comprises extracting the plurality of sets of projection data at the plurality of X-ray tube positions to minimize effects of shadows caused by the PCDs.
9. A computed tomography (CT) imaging apparatus, comprising:
an X-ray source configured to emit X-rays;
a plurality of photon-counting detectors (PCDs) arranged in a circular ring between the X-ray source and a CT detector; and
processing circuitry configured to
cause the X-ray source and the CT detector to perform a helical scan of an object to obtain projection data;
perform reconstruction using the obtained projection data using a shadow-correction method to obtain volume data; and
project the volume data at a predetermined viewing angle to obtain a scanogram.
10. The apparatus according to claim 9 , wherein the processing circuitry is further configured to cause the helical scan to be performed using a dose lower than a dose used for a helical scan performed to obtain a CT image of the object.
11. The apparatus of claim 10 , wherein the X-ray source includes two X-ray emitters that are spatially and spectrally distinct.
12. The apparatus of claim 10 , wherein the X-ray source is configured to perform kV-switching and modulation.
13. A method to obtain a scanogram for a hybrid scanner that includes a ring of sparse, fixed photon-counting detectors (PCDs) and an X-ray source and a CT detector that rotate together, the method comprising:
causing the X-ray source and the CT detector to perform a helical scan of an object to obtain projection data;
performing reconstruction using the obtained projection data using a shadow-correction method to obtain volume data; and
projecting the volume data at a predetermined viewing angle to obtain the scanogram.
14. The CT method according to claim 13 , wherein the step of performing the helical scan further comprises performing a helical scan using a dose lower than a dose used for a helical scan performed to obtain a CT image of the object.