High temporal resolution and streak-free four-dimensional cone-beam computed tomography

Area of Science:

• Medical Physics
• Radiotherapy Imaging
• Image Reconstruction

Background:

• Cone-beam computed tomography (CBCT) is crucial for image-guided radiation therapy (IGRT) but suffers from respiratory motion artifacts in chest/abdomen scans.
• Respiratory-gated 4D CBCT improves motion handling but undersampling causes streaking artifacts and reduced contrast resolution.

Purpose of the Study:

• To develop a novel method for artifact-free 4D CBCT reconstruction with high temporal resolution.
• To overcome the trade-off between temporal resolution and image quality in respiratory-gated CBCT.

Main Methods:

• Implementation of a prior image constrained compressed sensing (PICCS) algorithm.
• Reconstruction of streak-free 4D CBCT images using vastly undersampled projection data and a fully sampled prior image.
• Validation through numerical simulations and experimental phantom studies.

Main Results:

• Achieved high temporal resolution (approx. 100 ms) and artifact-free 4D CBCT image volumes.
• PICCS enabled accurate reconstruction from as few as 10-20 projections per phase.
• Demonstrated that PICCS decouples temporal resolution from streaking artifact levels.

Conclusions:

• The proposed PICCS method effectively mitigates undersampling artifacts in 4D CBCT.
• This technique enhances image quality and temporal resolution for improved IGRT.
• PICCS offers a promising solution for motion management in thoracic and abdominal radiotherapy.