Model-based CBCT scatter correction with dual-layer flat-panel detector.

Area of Science:

• Medical Imaging
• Radiological Physics
• Computational Imaging

Background:

• Dual-layer flat-panel detector (DL-FPD) based dual-energy cone-beam CT (CBCT) imaging is gaining popularity.
• Image quality in dual-energy CBCT is limited by Compton scattered x-ray photons.

Purpose of the Study:

• To develop and validate a novel scatter correction method, named e-Grid.
• To improve image quality in DL-FPD based CBCT imaging.

Main Methods:

• Approximated a linear signal model between low-energy (LE) and high-energy (HE) primary and scatter signals.
• Validated the model using physical calibration experiments and Monte Carlo simulations (GATE).
• Performed physical validation on a DL-FPD benchtop CBCT system using water, head, and abdominal phantoms to measure non-uniformity (NU) and assess multi-material decomposition.

Main Results:

• The e-Grid method accurately predicted scatter distributions in shape and intensity.
• Achieved uniform CBCT images with reduced shading artifacts in both LE and HE images.
• Demonstrated effectiveness across various phantom sizes (10-28 cm diameter).
• Reduced NU by over 77% (LE) and 66% (HE), substantially improving multi-material decomposition accuracy (iodine, gadolinium).

Conclusions:

• The e-Grid method effectively reduces Compton scattered x-ray signals in DL-FPD dual-energy CBCT.
• This leads to improved image quality and accuracy for advanced imaging applications.