Quality Assurance of 4D-CT Scan Techniques in Multicenter Phase III Trial of Surgery Versus Stereotactic Radiotherapy (Radiosurgery or Surgery for Operable Early Stage (Stage 1A) Non-Small-Cell Lung Cancer [ROSEL] Study)

Notable differences were seen in the 4D-CT imaging protocols for SBRT among centers. However, the observed deviations in target volumes were generally small. They were slightly larger for the mid-ventilation phases and smallest for the end-expiration phases. Steps to optimize and standardize the 4D-CT scanning protocols for SBRT are desirable.