Directional interpolation for motion weighted 4D cone-beam CT reconstruction

Area of Science:

• Medical Imaging
• Radiotherapy Physics
• Image Reconstruction

Background:

• Four-dimensional cone-beam computed tomography (4D CBCT) is crucial for image-guided radiotherapy.
• Image quality is often degraded by streaking artifacts and motion blur due to limited projections and patient movement during scanning.
• Existing methods struggle to adequately address both artifact reduction and motion compensation simultaneously.

Purpose of the Study:

• To develop and validate a novel framework for enhancing 4D CBCT image quality.
• To reduce streaking artifacts and image blur in 4D CBCT reconstructions.
• To improve the accuracy and reliability of 4D CBCT for clinical applications.

Main Methods:

• A framework combining improved motion and stationary regions of CBCT was proposed.
• Directional interpolation was used to decrease streaking artifacts in 4D CBCT projections.
• Deformable image registration estimated motion, assigning voxel-specific weights for a weighted combination of 3D and interpolated 4D images.

Main Results:

• The proposed method successfully decreased streaking artifacts in 4D CBCT images.
• Image blur was reduced, leading to improved overall image quality.
• Validation with both phantom and clinical data confirmed the effectiveness of the framework.

Conclusions:

• The developed framework effectively enhances 4D CBCT image quality by mitigating artifacts and blur.
• This approach offers a promising solution for improving visualization in image-guided radiotherapy.
• The combined motion and stationary region strategy provides superior image reconstruction compared to conventional methods.