ESTRO 2024 - Abstract Book

S4250

Physics - Intra-fraction motion management and real-time adaptive radiotherapy

ESTRO 2024

Similar results were found for the interfraction motion: for the rectumprostate, the rectumrectum and the tumour rectal, median HD95 values were 11.01 [9.67 – 17.75], 7.74 [6.26 – 10.54], and 5.53 [3.40 – 9.96] mm (p<0.001), respectively, and median MDTA values were 3.73 [3.10 – 4.58], 2.60 [2.17 – 3.13], and 1.81 [1.26 – 2.66] mm (p<0.0001), respectively.

Finally, the more the distance from the ARJ, the greater the inter- and intrafraction motion of the rectumprostate and the tumour wall (p<0,05). This correlation was not found for the rectumrectum (Figure 2).

Conclusion:

We evaluated the rectum motion in patients without and with a rectal tumour. We found that a longer RT session is correlated with a higher intrafraction motion in all cases. The presence of a rectal tumour and the distance from the ARJ could explain the intrafraction and interfraction rectum motion variability. These results constitute a new step towards increasingly personalised pelvic RT, especially regarding dose escalation with rectal boost delivery.