Table 1.

Recommendations for intrafraction motion monitoring during stereotactic radiotherapy with optical surface monitoring system

Issue	Recommendations
Thermal drift	Determine time for thermal drift equilibrium Turn on projectors before patient treatment
Couch walk‐out	Measure couch walk‐out (EPID, dial gauge, etc.) Phantom study to compare walk‐out with real time deltas (RTDs)
RTD dependence on surface‐to‐isocenter distance	Advanced camera optimization upgrade
Increase in RTDs at non‐zero couch angles	Perform cold calibration detailed in customer information bulletin
RTD exceeds thresholds at non‐zero couch angles	Return couch to zero and evaluate RTDs
RTD exceeds thresholds at couch zero	Repeat radiographic image guidance