Tumor tracking and motion compensation with an adaptive tumor tracking system (ATTS): system description and...

Area of Science:

• Medical Physics
• Radiation Oncology
• Robotics

Background:

• Tumor motion during radiation therapy, particularly in the lungs, poses a significant challenge to accurate treatment delivery.
• Real-time tumor tracking and motion compensation are crucial for improving the efficacy and safety of radiotherapy.

Purpose of the Study:

• To describe and evaluate a novel system for real-time tumor tracking and motion compensation using a robotic HexaPOD treatment couch.
• To assess the system's performance in compensating for breathing-induced tumor motion without implanted fiducial markers.

Main Methods:

• A system combining portal imaging with the therapeutic megavoltage beam for tumor tracking and optical markers for abdominal breathing motion tracking was developed.
• The robotic HexaPOD treatment couch's performance was evaluated using a 4D-phantom simulating patient tumor trajectories.
• System dynamics, including maximum speed and acceleration, were characterized.

Main Results:

• The system achieved real-time tumor tracking and motion compensation, reducing tumor motion amplitude by up to 68%.
• Baseline drifts in mean tumor position for realistic lung tumor trajectories were fully compensated.
• The HexaPOD couch demonstrated dynamic capabilities with maximum speeds of 8-9.5 mm/s and accelerations of 29.5-34.5 mm/s².

Conclusions:

• The developed adaptive tumor tracking system is technically feasible for compensating breathing-induced lung tumor motion.
• This novel approach offers a promising strategy for enhancing precision in lung cancer radiotherapy.