Systems and methods for computed tomography

A method for a photon-counting computed tomography (PCCT) system, the method comprising:

• during scanning using the PCCT system:
• applying a first current to an X-ray source of the PCCT system for a first portion of the view;
• applying a second current to the X-ray source for a second portion of the view;
• for each detector of the PCCT system:
• applying a first pile-up correction to a first photon count output by the detector during the first portion of the view to generate a corrected first photon count, and applying a second pile-up correction to a second photon count output by the detector during the second portion of the view to generate a corrected second photon count, the first pile-up correction applied to the first photon count based on the second pile-up correction applied to the second photon count;
• summing the corrected first photon count and the corrected second photon count to generate a total output photon count for the detector;
• and
• reconstructing an image based on the total output photon count at each detector.

A photon-counting computed tomography (PCCT) system, comprising:

• an X-ray source that emits a beam of X-rays toward a subject to be imaged;
• a photon-counting detector that receives the beam of X-rays attenuated by the subject;
• a data acquisition system (DAS) operably connected to the detector;
• and
• a computer comprising non-transitory memory and operably connected to the DAS, wherein the computer is configured with instructions in the non-transitory memory that when executed cause the computer to:
• for each view n scanned by the PCCT system:
• adjust an Automatic Exposure Control (AEC) current modulation to alternately increase an X-ray tube output current of the PCCT system above a prescribed current and decrease the X-ray tube output current below the prescribed current, the AEC current modulation determined by an AEC modulation function including a correction for pile-up;
• collect a first photon count at each detector of the PCCT system at the increased X-ray tube output current;
• collect a second photon count at each detector at the decreased X-ray tube output current;
• apply a first pile-up correction to the second photon count at each detector to obtain a corrected second photon count, the first pile-up correction based on the second photon count;
• apply a second pile-up correction to the first photon count at each detector to obtain a corrected first photon count, the second pile-up correction based on the first pile-up correction and the corrected second photon count;
• add the first corrected photon count to the second corrected photon count at each detector to obtain a total output photon count at each detector;
• and
• reconstruct an image based on the total output photon count at each detector, and output the image to a display device of the PCCT system.