Method for detecting and handling detector pixels with intermittent behavior for a small pixelated photon counting computed tomography (CT) system
AssigneeCanon Medical Systems Corporation
InventorsXiaohui Zhan, Ruoqiao Zhang, Cameron Clarke, Yi Qiang
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Abstract
An apparatus and a method for detection of defective pixels for a photon-counting detector-based computed tomography (CT) system is disclosed. In particular, the apparatus and the method disclosed herein, detect detector pixels that have intermittent behavior using on-the-fly defective pixel screening based on various criteria during an object scan. The defective pixels are discarded using a defective pixel map before image reconstruction.
Claims16
A photon-counting computed tomography (CT) apparatus, comprising:
- processing circuitry configured to
- receive a first defective pixel map of a detector of the apparatus, wherein the first defective pixel map is generated from results of a calibration scan;
- perform a scan of a patient;
- determine a second defective pixel map based on results of the scan of the patient;
- update the first defective pixel map based on the determined second defective pixel map,
- reconstruct an image from results of the scan of the patient by utilizing the updated first defective pixel map, and
- cause a display to display the image,
- wherein in determining the second defective pixel map, the processing circuitry is further configured to, for each pixel of a plurality of pixels of the detector:
- determine an energy spectrum of received photons received at the pixel, and determine whether the pixel is defective based on the determined energy spectrum of the pixel.
A method for determining a defective pixel of a detector of a photon-counting computed tomography (CT) apparatus, the method comprising:
- receiving a first defective pixel map of the detector, wherein the first defective pixel map was generated from results of a calibration scan;
- performing a scan of a patient;
- determining a second defective pixel map based on results of the scan of the patient;
- updating the first defective pixel map based on the determined second defective pixel map,
- reconstructing an image from results of the scan of the patient by utilizing the updated first defective pixel map, and
- causing a display to display the image,
- wherein the determining step further comprises, for each pixel of a plurality of pixels of the detector:
- determining an energy spectrum of received photons received at the pixel, and determining whether the pixel is defective based on the determined energy spectrum of the pixel.
A photon-counting computed tomography (CT) apparatus, comprising:
- a photon-counting detector;
- and
- processing circuitry configured to
- receive a first defective pixel map of the photon-counting detector, wherein the first defective pixel map is generated from results of a calibration scan;
- determine an energy spectrum of received photons for each pixel of a plurality of pixels of the photon-counting detector;
- determine a second defective pixel map based on a count value in a pre-determined energy bin of the determined energy spectrum of the pixel;
- update the first defective pixel map based on the determined second defective pixel map;
- reconstruct an image from results of the scan of the patient by utilizing the updated first defective pixel map;
- and
- cause a display to display the image,
- wherein in determining the second defective pixel map, the processing circuitry is further configured to, for each pixel of a plurality of pixels of the detector:
- determine an energy spectrum of received photons received at the pixel, and determine whether the pixel is defective based on the determined energy spectrum of the pixel.
Dependencies are inferred from the claim text.