Comparative study of respiratory motion correction techniques in cone-beam computed tomography

Area of Science:

• Medical Imaging
• Radiotherapy Physics
• Image-Guided Interventions

Background:

• Image-guided radiotherapy (IGRT) relies on accurate tumor visualization.
• Respiratory motion significantly degrades cone-beam computed tomography (CBCT) image quality.
• Traditional 3D CBCT and 4D CBCT have limitations in addressing motion artifacts.

Purpose of the Study:

• To compare the clinical utility of motion-compensated (MC) CBCT against 4D CBCT and 3D CBCT.
• To evaluate image quality, tumor positioning accuracy, and motion amplitude quantification.
• To determine the optimal CBCT technique for stereotactic body radiation therapy (SBRT).

Main Methods:

• Reconstruction of 3D, 4D, and MC CBCT from 48 SBRT patients' acquisitions.
• Quantitative analysis of image quality using correlation ratio with planning CT.
• Assessment of tumor positioning accuracy and motion amplitude.

Main Results:

• MC CBCT demonstrated superior image quality (79%/74%) compared to 3D (74%/70%) and 4D CBCT (67%/47%).
• MC CBCT and 4D CBCT corrected for respiratory motion, but 4D CBCT showed streak artifacts.
• Tumor positioning accuracy with MC CBCT was significantly better than 3D CBCT (p<0.0001).

Conclusions:

• Both 4D and MC CBCT enable accurate tumor positioning under respiratory motion.
• MC CBCT provides adequate image quality with shorter acquisition times than 4D CBCT.
• MC CBCT is a valuable replacement for 4D CBCT in clinical protocols, especially for patients with large tumor motion.