A prospective randomized study comparing two frameless immobilization systems for cranial stereotactic radiotherapy.

Introduction: The Dual Shell Encompass Fibreplast™ System (DS-Encompass) by CQ Medical™ is validated for frameless immobilization in stereotactic brain radiotherapy. An alternative mask model has been proposed with the rear shell replaced by a Moldcare® cushion (M-Encompass). To validate the use of this model in our cranial stereotactic workflow method including HyperArc™, we performed a prospective randomized study comparing inter-and intrafractional motion and patients comfort between both masks.