Real-time intra-fraction-motion tracking using the treatment couch: a feasibility study

Area of Science:

• Medical Physics
• Radiation Oncology
• Robotics in Medicine

Background:

• Respiration-induced tumor motion causes significant deviations in planned radiation treatments.
• This motion can lead to underdosing of tumors and overdosing of critical surrounding structures.
• Current motion management techniques like breath-holds and gating are time-consuming, while MLC-based tracking is limited to 2D.

Purpose of the Study:

• To present and evaluate a novel real-time robotic couch system for compensating organ motion during radiation therapy.
• To demonstrate proof-of-principle using a miniature adaptive couch model.
• To assess the effectiveness of a real-time couch compensation system with a robotic couch (Hexapod).

Main Methods:

• Developed and tested a miniature adaptive couch model with a feedback loop to simulate tumor and couch motion.
• Utilized a stereoscopic infra-red camera system interfaced with a robotic Hexapod couch for real-time motion detection and compensation.
• Conducted film-based experiments with solid water phantoms to evaluate dose distributions under static and motion conditions.

Main Results:

• The miniature couch model successfully compensated for phantom motion, yielding dose distributions comparable to static geometry.
• The real-time robotic couch system achieved near-equivalent dose distributions (
• The system demonstrated effectiveness for both fixed field and dynamic arc delivery cases.

Conclusions:

• Real-time robotic couch motion compensation is a viable alternative to existing methods for managing respiration-induced tumor motion.
• This technology has the potential to improve radiation therapy accuracy and patient outcomes by ensuring precise dose delivery.
• Further investigation and clinical implementation of robotic couch tracking systems are warranted.