Accuracy And Stability Of Deep Inspiration Breath Hold In Gated Breast Radiotherapy: A Comparison Of Two Tracking And Guidance Systems

•CatalystHD biofeedback-based surface imaging system improved breath-hold accuracy over a Calypso audio feedback based system.•Patients treated using CatalystHD showed increased stability of breath-hold motion during treatment over Calypso system.•Increased stability and accuracy in biofeedback-based system was consistent throughout course of radiation therapy treatment.