Performance of Makerless Tracking for Gimbaled Dynamic Tumor Tracking

Area of Science:

• Medical Physics
• Radiation Oncology
• Image-Guided Therapy

Background:

• The Vero 4DRT system has introduced a new markerless dynamic tumor tracking (MLDTT) method.
• Accurate tumor tracking is crucial for effective radiation therapy, especially for moving targets.

Purpose of the Study:

• To report the workflow and assess the accuracy of the novel markerless dynamic tumor tracking (MLDTT) method.
• Evaluate the performance of the MLDTT feature integrated with the ExacTrac 3.6.1 software on the Vero 4DRT system.

Main Methods:

• Phantom measurements using a QA tool and a patient breathing curve to simulate motion.
• Comparison of MLDTT-detected target positions against defined positions.
• Log-file analysis of treatment data from eight patients treated with MLDTT.

Main Results:

• MLDTT detection accuracy achieved was 0.12mm ± 0.12mm (x-axis), 0.12mm ± 0.11mm (y-axis), and 0.20mm ± 0.21mm (z-axis).
• Treatment accuracy is comparable to marker-based dynamic tumor tracking (DTT) on the Vero system and reported values for CyberKnife's XSight Lung.
• Median treatment time was 21 minutes and 34 seconds, with 175kV images used for motion monitoring.

Conclusions:

• The MLDTT algorithm offers accuracy comparable to marker-based methods and other leading systems.
• Successful treatment of eight patients using MLDTT confirms its clinical applicability.
• Treatment durations with MLDTT are similar to standard DTT procedures, indicating workflow efficiency.