First clinical evaluation of breathing controlled four-dimensional computed tomography imaging

Area of Science:

• Medical Imaging
• Radiotherapy Physics
• Computational Imaging

Background:

• Four-dimensional computed tomography (4DCT) is crucial for radiotherapy planning.
• Artifacts frequently compromise 4DCT image quality.
• A novel breathing controlled 4DCT (i4DCT) algorithm has been developed.

Purpose of the Study:

• To present the initial clinical data for the i4DCT algorithm.
• To evaluate the image quality achieved with i4DCT.
• To assess projection data coverage and beam-on time for i4DCT.

Main Methods:

• Analysis of 129 i4DCT scans from patients with thoracic tumors.
• Evaluation of projection data coverage and beam-on time.
• Expert review of image quality for a challenging subgroup (n=30) with varied breathing patterns, using amplitude- and phase-based reconstructions.

Main Results:

• 78% (amplitude-based) and 63% (phase-based) of challenging cases were artifact-free (rating ≥4).
• Average beam-on time was 4.9 ± 1.6 s; no significant increase for the challenging subgroup.
• Median projection data coverage was 93% (inhalation) and 94% (exhalation); slight significant decrease in challenging cases.

Conclusions:

• The i4DCT algorithm demonstrates very promising clinical results.
• High image quality and robust projection data coverage were achieved.
• Findings support previous i4DCT phantom study results.