ESTRO 2023 - Abstract Book

S413

Sunday 14 May 2023

ESTRO 2023

Results An example of a fit together with the residuals is shown in the middle of fig. 1. The mean reduced χ 2 of all fits is 0.110 ± 0.097 (1SD). Δ Z varied between -15.2 and 3.3 mm from the expected location (fig. 2 (bottom)). Large fluctuations (up to 46% (1SD)) are seen in the calibration factors for each probe (fig. 2 (top)). This is expected to stem from the re-attachment of the probe. Furthermore, the calibration factor for probe 1 and 2 increased over time, which indicates degradation of the probe sensitivity.