Apparatus and method for angular response calibration of photon-counting detectors in sparse spectral computed tomography imaging
AssigneesToshiba Medical Systems Corporation, Kabushiki Kaisha Toshiba
InventorsXiaolan WANG, Yu Zou
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Abstract
A method for detector angular response calibration in computed-tomography (CT) comprising capturing incident X-ray photons, emitted from an X-ray source, via a plurality of energy-discriminating detectors, determining photon counts of the captured incident X-ray photons in a plurality of energy windows at each energy-discriminating detector, and adjusting the photon counts based on a pre-determined detector angular response calibration look-up table for a given view for each energy-discriminating detector at each energy window.
Claims12
A method for detector angular response calibration in computed-tomography (CT), the method comprising:
- capturing incident X-ray photons, emitted from an X-ray source at a given view using pre-determined scan parameters, via a plurality of energy-discriminating detectors;
- determining photon counts of the captured incident X-ray photons in a plurality of energy windows at each energy-discriminating detector;
- and
- adjusting the photon counts in each of the plurality of energy windows at each energy-discriminating detector based on a pre-determined detector angular response calibration look-up table.
A computed-tomography (CT) apparatus, comprising:
- a plurality of energy-discriminating detectors configured to capture incident X-ray photons emitted from an X-ray source at a given view using pre-determined scan parameters;
- and
- a processor configured to
- determine photon counts of the captured incident X-ray photons in a plurality of energy windows at each energy-discriminating detector;
- and
- adjust the photon counts in each of the plurality of energy windows at each energy-discriminating detector based on a pre-determined detector angular response calibration look-up table.
A method to determine a detector angular response calibration look-up table to calibrate angular responses of a plurality of energy-discriminating detectors in a computed-tomography (CT) apparatus, the method comprising:
- determining an initial detection efficiency parameter value for each of a plurality of combinations of incident angle and energy level by simulating a pre-determined number of single-energy photons at each combination of incident angle and energy level;
- calculating an incident spectrum on each energy-discriminating detector for each of a plurality of combinations of pre-determined scan parameters, energy level, and pre-determined patient attenuation parameters;
- performing a set of calibration scans using the plurality of combinations of pre-determined scan parameters with a phantom arranged within the CT apparatus, the phantom corresponding to the pre-determined patient attenuation parameters;
- measuring detected counts for each energy window at each energy-discriminating detector for each combination of pre-determined scan parameters and the pre-determined patient attenuation parameters;
- determining a detection efficiency parameter value corresponding to each energy window of each energy-discriminating detector, each combination of pre-determined scan parameters, and the pre-determined patient attenuation parameters, based on the initial detection efficiency parameter value, the incident spectrum, and the detected counts;
- and
- determining the detector angular response calibration look-up table based on the determined detection efficiency parameter values corresponding to each energy window of each energy-discriminating detector, the pre-determined scan parameters, and the pre-determined patient attenuation parameters.
An apparatus to determine a detector angular response calibration look-up table to calibrate angular responses of a plurality of energy-discriminating detectors in a computed-tomography (CT) apparatus, the apparatus comprising:
- a processor configured to
- determine an initial detection efficiency parameter value for each of a plurality of combinations of incident angle and energy level by simulating a pre-determined number of single-energy photons at each combination of incident angle and energy level;
- calculate an incident spectrum on each energy-discriminating detector for each of a plurality of combinations of pre-determined scan parameters, energy level, and pre-determined patient attenuation parameters;
- perform a set of calibration scans using the plurality of combinations of pre-determined scan parameters with a phantom arranged within the CT apparatus, the phantom corresponding to the pre-determined patient attenuation parameters;
- measure detected counts for each energy window at each energy-discriminating detector for each combination of pre-determined scan parameters and the pre-determined patient attenuation parameters;
- determine a detection efficiency parameter value corresponding to each energy window of each energy-discriminating detector, each combination of pre-determined scan parameters, and the pre-determined patient attenuation parameters, based on the initial detection efficiency parameter value, the incident spectrum, and the detected counts;
- and
- determine the detector angular response calibration look-up table based on the determined detection efficiency parameter values corresponding to each energy window of each energy-discriminating detector, the pre-determined scan parameters, and the pre-determined patient attenuation parameters.
Dependencies are inferred from the claim text.