S2875
RTT - RTT education, training, and advanced practice
ESTRO 2026
Implementing MRI-in-treatment-position for HPB radiotherapy required extensive sequence optimisation, documentation, and staged multidisciplinary coordination. Diagnostic radiographers and RTTs played complementary roles in developing and delivering the workflow, demonstrating that shared professional oversight can enable safe, efficient, and clinically relevant imaging integration. Although resource-intensive, the process proved achievable through structured planning, protected time, and institutional support. This staged approach addresses a key evidence gap in MRI workflow development and provides a scalable model for advanced imaging adoption within value-based radiotherapy practice. Keywords: MRI, motion management, implementation Quantifying the Dosimetric Impact of Daily Anatomical Variations in Breast Radiotherapy Using Automated Cone Beam CT (CBCT) Based Dose Reconstruction Shivani Kumar 1 , Adam Mylonas 2 , Brendan Whelan 2 , Sean Pollock 3 , Michael Jameson 4 , Doan Trang Nguyen 1 , Paul Keall 1,5 1 Clinical Research, SeeTreat, Sydney, Australia. 2 Engineering, SeeTreat, Sydney, Australia. 3 Product Development, SeeTreat, Sydney, Australia. 4 Radiation Oncology, GenesisCare, Sydney, Australia. 5 ImageX Institute, University of Sydney, Sydney, Australia Mini-Oral 3172
centre collaboration, MDT consultation, and vendor engagement to identify suitable sequences. Diagnostic protocols from two NHS sites and ten retrospective hepatobiliary cases informed initial selection. Institutional approval was obtained for a staged pathway comprising development, phantom, healthy volunteer, and patient imaging phases under the existing MRI consenting framework. A ten-patient feasibility study was authorised.Sequences were iteratively tested in phantoms and refined in eight healthy volunteers. Subsequently, patient imaging was performed in treatment position using MR-compatible immobilisation, breath hold (BH), and abdominal compression (AC), jointly conducted by a diagnostic radiographer and RTT. Cine MRI was adapted to assess liver motion, with all datasets exported to the radiotherapy planning system, except cine sequences, which were exported to PACS. For each phase, data were collected on sequence type, imaging parameters and staff present. Results: The programme spanned July 2022–February 2025 (31 months), progressing from phantom testing to completion of the ten-patient feasibility phase. Eight volunteers and ten patients were scanned successfully without adverse events. Sequence evaluation guided protocol optimisation. Iterative testing of T1-, T2-, diffusion-, and balanced FFE cine acquisitions established optimal combinations for image quality, motion control, and export compatibility. The iterative process and finalised MRI sequences are shown in Table 1.Initial sessions required a diagnostic radiographer, RTT, radiologist, and physicist. As parameters and documentation stabilised, scanning was streamlined to a two-person (radiographer and RTT) operation with remote MDT input, where required. Efficiency improved through structured MDT planning, protected scanner time, and progressive workflow standardisation.
Purpose/Objective: In breast radiotherapy (RT), daily anatomical
variations, particularly involving the radiosensitive heart1 and chest wall can occur even when patient setup appears within tolerance on surface guidance or respiratrory guided verification. Current clinical workflows lack efficient tools to routinely quantify the resulting dosimetric impact, leaving uncertainty as to whether such variations have a clinically relevant effect on delivered dose. The aim of this study was to evaluate the impact of an automated software solution that integrates daily cone beam CT (CBCT) images to calculate delivered dose distributions that quantifies dosimetric deviations arising from inter- fraction anatomical changes during breast RT. Material/Methods: Five patients (at least 15 fractions each) who received deep inspiration breath-hold (DIBH) breast RT with surface-guided or respiratory assisted positioning were included from an ethics-approved retrospective patient dataset (2024-09-1157). For each fraction, cone beam CT (CBCT) images were automatically processed by the software. For each CBCT, deformable
Conclusion:
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