Fig. 4

Cases with large discrepancies in the registration error between MIM and Velocity. a Proton beams at 74 GyE were delivered to the tumor in S3 14.2 months before. The fiducial registration error was 3 mm in MIM and 18 mm in Velocity, the largest discrepancy (Velocity-MIM) among all the patients. b Proton beams at 72.6 GyE were delivered to the tumor in S7 8.9 months before. The fiducial registration error was 18.1 mm in MIM and 4.7 mm in Velocity, the largest discrepancy (MIM-Velocity) among all the patients