Feasibility of breath-hold gating with visual-tactile guidance on an MR-Linac

This study aimed to assess a visual-tactile breath-hold (BH) workflow integrated with Elekta Unity's comprehensive motion management (CMM) system for gated MR-guided radiotherapy in situations where verbal coaching is impractical. A visual guidance program and a 3D-printed couch-mounted tactile pointer were implemented to instruct patients and stabilize voluntary BH. Two patients, one with pancreatic cancer and one with lung cancer, were treated using this workflow. Treatment beam gating was driven by CMM BH criteria, and audit log files from CMM-guided treatments were analyzed. Expected gating efficiencies were 40% for the pancreas case and 51.4% for the lung case, while measured efficiencies were 42.59 ± 2.56% and 54.95 ± 0.54%, respectively. The corresponding beam-on times were 14.75 ± 0.96 and 16.25 ± 0.50 min. The workflow reduced reliance on motion prediction for gating and mitigated frequent beam holds typically observed with free-breathing strategies, thereby decreasing dosimetric uncertainty. These findings indicate that a visual-tactile BH workflow on a 1.5 T MR-Linac is feasible and practical, supporting efficient gated delivery and reproducible breath-holds when verbal coaching is limited.