S2838
RTT - RTT education, training, and advanced practice
ESTRO 2026
Roadmap for RTT-led Online Adaptive MR-Guided Radiotherapy Ana Margarida Costa 1 , Dina Gonçalves 1 , Christelle Bouchart 1,2 , João Perdigão 1 , Leonor Saavedra 1 , Madeline Michel 1 , Paulo Ferreira 3 , Robbe Van den Begin 1 , Sara Poeta 3 , Zelda Paquier 3 , Akos Gulyban 3 , Nicolas Jullian 1 1 Radiation Oncology Department, Institut Jules Bordet, Hopital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium. 2 Laboratory of Experimental Gastroenterology, Université Libre de Bruxelles, Brussels, Belgium. 3 Medical Physics Department, Institut Jules Bordet, Hopital Universitaire de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium Purpose/Objective: Magnetic Resonance-Guided Adaptive Radiotherapy (MRgART) enables the development of personalised, daily online adapted treatment plans. This approach is resource-intensive, requiring the continuous presence of Radiation Oncologists (ROs), Physicists, and Radiation Therapists (RTTs). To optimize workflow efficiency, our MR Linac team developed an RTT-driven contouring adapt-to-shape (ATS) workflow for prostate cancer MRgART. This work aims to describe its implementation and initial clinical evaluation, assessing its feasibility, safety, and impact on treatment time and resource utilisation. Material/Methods: This workflow was implemented in three phases. In Phase 1 RTTs engaged in self-directed learning: anatomy review, international guidelines and offline contouring practice. ProKnow and Treatment Planning System (TPS) Monaco (ELEKTA®) were used to contour practice. Phase 1 was concluded upon referral RO approval of the TPS Monaco practice contours. Phase 2 included online contouring with mandatory validation by ROs. During this phase, contouring and verification times were systematically recorded. In Phase 3, after achieving consistent contouring quality, defined as ≥ 10 cases rated as “no impact” or “minor impact”, RTTs proceeded without online RO validation. Additionally, an internal survey was conducted amongst RTTs and ROs involved in MR-Linac treatments to identify contouring challenges and assess the frequency of ROs revisions, providing insights into areas requiring standardisation and targeted training. Results: Offline contour training using TPS Monaco improved the hands-on skills due to identical software functionalities and interface. This new workflow successfully allowed RTTs to assume contouring duties, while ROs focused on plan verification and physicists on dosimetry. Survey data revealed high ROs satisfaction (40% satisfied and 60% very satisfied)
patient was anonymized and imported into the Velocity program, where the matching process occurs. All 5 ROs, along with the APRT, conducted matching on the 150 CBCTs in an offline environment. The differences in direction between the matches made by the APRT and the ROs will be recorded and analyzed. Interclass correlation coefficients will be calculated to evaluate the variability and the degree of concordance between the APRT and the ROs. Results: Analysis was performed by averaging the matching of the 5 ROs against the APRT (1:1). The comparison of CBCT matching between the 2 groups shows a robust positive linear correlation, with a coefficient of determination (R2) of 0.9843, 0.9948 and 0.9985 in the X, Y and Z directional respectively. This result also indicates a high level of concordance (p<0.05) between the matching of the 2 groups. With the CBCT matching of RO in-charge as the gold standard, comparison is also made against the other 4 ROs. Results show the widest discrepancy value of +10mm at Z direction with the X and Y direction values within ±3.8mm. Similarly, comparison with the APRT matching values also shows the widest discrepancy value of +8.6mm in the Z direction, with the X and Y direction values within ±2.5mm. The APRT CBCT matching for 2 patients showed values in 2 axis that are beyond the widest discrepancy of the other 4 ROs but within ±2.5mm when compared to the RO in-charge's matching. Conclusion: The result of the CBCT matching compared between the HNN APRT and the HNN ROs shows a high-level concordance. This agreement of the HNN APRT’s CBCT matching across HNN ROs helps to provide evidence in support of the potential shift of CBCT image approval from the ROs to HNN APRT. Keywords: CBCT, HNN, APRT References: 1) Lee, Grace & Harnett, Nicole & Zychla, Laura & Dinniwell, Robert. (2012). Radiotherapy Treatment Review: A Prospective Evaluation of Concordance between Clinical Specialist Radiation Therapist and Radiation Oncologist in Patient Assessments. Journal of Medical Imaging and Radiation Sciences. 43. 10.1016/j.jmir.2011.10.001. 2) Sin SY, Chua MLK, Wong SMM, Sommat K, Lin XY, Ng YY, Soong YL. An evaluation of concordance between head and neck advanced practice radiation therapist and radiation oncologists in toxicity assessment for nasopharyngeal carcinoma patients. Tech Innov Patient Support Radiat Oncol. 2021 Sep 4;19:52-56. doi: 10.1016/j.tipsro.2021.08.001. PMID: 34527820; PMCID: PMC8430423.
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