Fig. 3.

Total baseline drift in the anterior-posterior direction at the end of the fraction listed per patient. Drift is decomposed in a component of the IGRT procedure (image acquisition and evaluation) and treatment. Fractions in pink indicate that the patient performed a non-monotonic drift and returned closer to the baseline position after the IGRT procedure. The majority of drift occurs during the IGRT procedure compared to treatment delivery and is in the posterior direction. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)