ESTRO 2024 - Abstract Book

S5538

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2024

Figure 2 - Percentage of fractions in which the intra-fraction motion in one or more directions exceeds the PTV margin of 1, 2 and 3 mm isotropically in all directions.

Conclusion:

Intrafraction motion of pelvic lymph nodes depends on their localization in online adaptive MR-guided RT. Lymph nodes located in the mesorectum show larger intra-fraction motion compared to the paraaortic, parailiac and obturator nodes. A PTV margin of 3 mm for the mesorectal nodes and 2 mm for the other locations ensures that the target is inside the PTV for 90% of the fractions.

Keywords: pelvic nodes, intrafraction motion, MR-guided ART

1361

Digital Poster

Use of shoulder shell immobilisation for radical Head and Neck Radiotherapy

Deborah L Thornberry, Ruth McLauchlan, Meagan De La Bastide, Dorothy M Gujral, Shahlaa Alkhalifa

Imperial College Healthcare NHS Trust, Radiotherapy, London, United Kingdom

Purpose/Objective: