C-RAD has noted a potential issue affecting the CSRs mode of the Catalyst+ HD and Catalyst HD systems. The issue is that the stated precision of the catalyst system for stereotactic radiosurgery (SRS) treatments cannot be guaranteed for all couch angles and system setups. in certain cases, the system may indicate the patient as correctly positioned at the isocenter, even when the isocenter is positioned outside of the indicated tolerance. This could in the worstcase result in erroneous dose delivery.