A Visual Breath-Hold Coaching System to Enhance Patient Guidance during MR-Guided Radiotherapy
Abstract
Purpose
Patient coaching on the Elekta Unity MR-Linac is challenged by an enclosed bore that limits direct observation and by high acoustic noise during MR imaging that can reduce comprehension of verbal commands. We developed a synchronized, dual-interface visual coaching system to supplement therapist audio instructions and deliver clear breath-hold guidance for motion management.
Methods
A Python application was implemented with a therapist controller and a patient-facing full-screen display. Therapists configure preparation/hold/recovery durations, start sequences, monitor progress with a live timeline, and extend or terminate breath-holds as clinically needed. Custom short messages can be pushed in real time for reassurance or minor setup corrections. The patient display provides phase-specific cues: animated breathing during preparation, an unambiguous “HOLD” state with a countdown visualization, and recovery prompts; optional ball-press imagery reinforces tactile feedback cues. To assess display preferences, test subjects compared real-time anatomy, coaching visuals, and a tracking-only view with anatomy obscured. The two interfaces remain synchronized via socket-based messaging. The system supports English/Spanish and is packaged as standalone executables requiring no additional software installation.
Results
The system consistently delivered structured, synchronized coaching sequences while preserving full therapist control. On-screen messaging provided an alternative communication pathway when audio coaching was degraded by MRI noise. Phase color cues (blue preparation, green hold, red recovery) enabled rapid patient recognition of the current breathing state, reducing reliance on spoken instructions alone. During preference testing, some subjects reported favoring the coaching-only display over viewing real-time anatomy, indicating that anatomical structures were not necessary for effective breath-hold guidance.
Conclusion
A visual coaching display mitigates communication constraints inherent to MR-guided radiotherapy and standardizes breath-hold instruction delivery. By combining synchronized visual cues with therapist-controlled timing and real-time messaging, the system strengthens breath-hold guidance when audio instructions are limited and supports consistent execution of coached breath-holds during Unity treatments.