Extraction of tumor motion trajectories using PICCS-4DCBCT: a validation study.

Area of Science:

• Medical Imaging
• Radiotherapy Physics
• Image Reconstruction

Background:

• 4D cone beam computed tomography (4DCBCT) is crucial for verifying tumor motion during radiotherapy.
• Traditional 4DCBCT methods often require slower gantry speeds or multiple rotations.
• A novel approach using prior image constrained compressed sensing (PICCS) with standard 1-minute data acquisition has been proposed.

Purpose of the Study:

• To validate the capability of the PICCS-4DCBCT method for extracting tumor motion trajectories.
• To assess PICCS-4DCBCT's performance using physical phantom, simulated, and in vivo human subject data.

Main Methods:

• Utilized a standard 1-minute gantry rotation Cone Beam CT acquisition.
• Applied deformable registration to extract motion trajectories from PICCS-reconstructed 4DCBCT images.
• Validated against programmed trajectories (physical phantom) and 4DCT ground truth (simulated data).

Main Results:

• PICCS-4DCBCT demonstrated high accuracy with root mean square errors (RMSEs) < 0.7 mm and maximum errors (MaxEs) < 1 mm.
• PICCS-4DCBCT showed insensitivity to breathing period variations in simulations.
• High-quality 3D tumor motion trajectories were obtained from in vivo data.

Conclusions:

• PICCS-4DCBCT combined with standard 1-minute acquisition enables accurate tumor motion trajectory delineation.
• This method provides a robust tool for radiotherapy planning and verification.