Related Experiment Video
Updated: Jun 19, 2025
08:18
High-Accuracy Correction of 3D Chromatic Shifts in the Age of Super-Resolution Biological Imaging Using Chromagnon
Published on: June 16, 2020
7.4K
A Novel and Reliable Pixel Response Correction Method (DAC-Shifting) for Spectral Photon-Counting CT Imaging
Navrit Johan Singh Bal1,2, Imaiyan Chitra Ragupathy1,2, Trine Tramm1,3
1Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark.
Tomography (Ann Arbor, Mich.)
|July 26, 2024
Summary
A new digital-to-analogue converter (DAC)-shifting method effectively corrects pixel response variations in spectral photon-counting CT imaging. This technique significantly reduces image artefacts and improves CT value uniformity, outperforming traditional methods.
Area of Science:
- Medical Imaging Physics
- Photon-Counting CT Technology
- Image Reconstruction and Artifact Correction
Background:
- Spectral photon-counting cone-beam computed tomography (CT) faces challenges due to individual pixel response variations, causing noisy projections and ring artifacts.
- Current correction methods, such as signal-to-thickness calibration (STC), often rely on calibration measurements or post-processing without explicitly addressing pixel response.
Purpose of the Study:
- To introduce and evaluate a novel post-processing method, digital-to-analogue converter (DAC)-shifting, for correcting individual pixel response in spectral photon-counting CT.
- To compare the efficacy of DAC-shifting against traditional STC methods in improving image quality and quantitative accuracy.
Main Methods:
- Developed the DAC-shifting method, which explicitly measures current pixel response using flat-field images to correct projection data.
- Evaluated DAC-shifting using spectral photon-counting imaging (Medipix3) of phantoms with varying densities and in iodine K-edge imaging.
- Compared DAC-shifting performance against polymethyl methacrylate (PMMA)-based STC correction.
Main Results:
- DAC-shifting demonstrated significant effectiveness in correcting pixel responses, achieving a 47.4% average reduction in CT-number variation in homogeneous materials.
- The method proved robust against detector instability, with CT-number variation reduction ranging from 40.7% to 55.6%.
- Compared to STC's variable results (13.7% average reduction), DAC-shifting provided sharper attenuation peaks and more uniform CT values in K-edge imaging.
Conclusions:
- The DAC-shifting method is a highly effective post-processing technique for correcting individual pixel responses in spectral photon-counting CT.
- DAC-shifting offers superior performance in reducing image artifacts and improving CT value uniformity compared to STC, particularly beneficial for quantitative imaging like iodine concentration measurements.
