ESTRO 2024 - Abstract Book

S4272

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

ESTRO 2024

Conclusion:

Based on the 183 examined fractions, there is a clear advantage of the use of adaptive irradiation plans in terms of dose coverage of the target volume, and doses to the examined organs at risk. Our retrospective dosimetric evaluation of online scheduled and adapted plans confirmed that the use of adaptive radiation therapy in patients with prostate cancer has a clear dosimetric advantage, but to find out if these dosimetrical differences have clinical effect needs further investigation.

Keywords: Prostate, Ethos, Dosimetry

References:

1. ADAPTIVE INTELLIGENCE™ CONSORTIUM Best Practices White Paper: Prostate Adaptive Radiotherapy with Ethos, online on 18.10.2023. at https://medicalaffairs.varian.com/download/AICProstateWhitePaper.pdf

1613

Proffered Paper

MLC tracking and dose accumulation validation on the MR-linac using a real-time deformable dosimeter

Madelon van den Dobbelsteen 1 , Pim T.S. Borman 1 , Laurie J.M. de Vries 1 , Sara L. Hackett 1 , Kalin Penev 2 , Rocco Flores 2 , Stephanie Smith 2 , Yoan LeChasseur 3 , Simon Lambert-Girard 3 , Benjamin Côté 3 , Peter L. Woodhead 1,4 , Lando S. Bosma 1 , Cornel Zachiu 1 , Bas W. Raaymakers 1 , Martin F. Fast 1 1 University Medical Center Utrecht, Radiotherapy, Utrecht, Netherlands. 2 IBA QUASAR, Modus Medical Devices Inc., London ON, Canada. 3 Medscint, -, Quebec City, Canada. 4 Elekta AB, -, Stockholm, Sweden

Purpose/Objective:

Online MRI acquired on the MR-linac can capture the full complexity of anatomical motion during treatment delivery. This time-resolved anatomical information is increasingly used to facilitate novel dose accumulation and (real-time) plan adaptation techniques. Unfortunately, the current lack of MRI-compatible deformable motion phantom with time-resolved dosimetry capability severely obstructs the successful end-to-end validation and subsequent clinical introduction of new radiotherapy adaptation workflows. In this study, we validate a newly-developed MRI-compatible prototype of a deformable motion phantom with six integrated Plastic Scintillation Dosimeters (PSD) in the context of deformable multi-leaf collimator (MLC) tracking and dose accumulation on the MR-linac.

Material/Methods: