Clinical Experience: Visualize the Potential Collision with the Real-Time Laser System
Abstract
Purpose
Collision risk between the patient/immobilization devices with gantry or the on-board imaging system remains a safety and workflow concern in modern radiotherapy. We built and implemented a real-time laser visualization system, enabling immediate assessment of potential collisions without a dry run. Additionally, we integrated collision prediction using ARIA couch position data to forecast potential collisions before the patient is brought into the treatment room. Here we report our clinical experience, including system stability, maintenance demands, and impact on treatment workflow and safety.
Methods
An isocentric ring of 40 laser diodes was designed to delineate a visible boundary of the potential collision zones. The patient CT scan, support structures, and isocenter coordinates from the Eclipse system are processed to predict potential collisions. Patient collision data and ring commands are transmitted to the ring’s programmable microcontroller, which independently controls the laser ring’s eight partitioned sectors; a sector-mapping algorithm translates predicted collision geometry into sector activations such that when a collision risk is forecast for a given sector, the corresponding lasers flash-illuminate to provide intuitive visual warnings to the RTT team. Moreover, with screw-based reinforcement to secure the laser position, the stability of the system was evaluated for laser drift by daily QA and transitioned to monthly QA after establishing stable performance.
Results
The system provided immediate visual indicators through sector-specific activations, driven by couch position and body contour prediction, offering proactive warnings. The laser alignment showed stable operation using screw-based mounting maintaining a reliable alignment with routine QA and exhibited less than 1mm drift over 6 months. The approach streamlined dry runs and improved team communication, with RTTs reporting high usability and confidence.
Conclusion
Clinically, real-time laser visualization enables earlier intervention, potential workflow efficiency gains, and improved patient safety. The low-maintenance design for long-term adoption and multicenter evaluation is planned.