A noninvasive realtime body position monitoring system for the entire course of tumor radiotherapy.

In tumor radiotherapy, monitoring patient body position is crucial for improving efficacy and reducing complications. We developed a contact-based body position monitoring system using pressure sensors and artificial intelligence, enabling non-invasive, radiation-free, real-time monitoring. The system consists of two pressure-sensitive mattresses with 6400 piezoresistive pressure points each, placed under the scapulae and sacrococcygeal region to monitor resistance values for center of gravity calculation. Using data from 251 cancer patients across 1046 sessions, a random forest algorithm achieved an area under the curve (AUC) of 0.995. Internal validation revealed a true positive rate (TPR) of 95.5% and accuracy (ACC) of 96.8%. Overall accuracy exceeded 90%, providing an effective and low-cost solution for continuous body position monitoring during radiotherapy.