ESTRO 2025 - Abstract Book

S2741

Physics - Dose prediction, optimisation and applications of photon and electron planning

ESTRO 2025

Target volume coverage, CI, HI, and GI were all improved using the hybrid technique (Figure 2). dMax increased from 27.7Gy to 28Gy.

Figure 2 - mean target coverage, conformity indices, homogeneity index and gradient index for dIMRT and hybrid plans Mean MU reduced from 976 (dIMRT) (s.d. 181.6, range 750-1329) to 825 (hybrid) (s.d. 57, range 773-995).

The overall ProKnow plan quality score increased from 76.3% (s.d. 5.6) to 86.7% (s.d. 3.1) using the scripted hybrid technique.

Conclusion: Scripting planning tasks are effective at reducing planning time and inter-user variability. Using a scripted hybrid planning technique, the time taken to produce an optimal 2-field breast plan has been significantly reduced without compromising plan quality. This technique is less reliant on planner experience and more straightforward to train. Implementation of scripted breast planning allows for better access to quality treatment for more patients.

Keywords: breast, automation, audit

References: Lima SM, K. R. (2021). Global breast cancer incidence and mortality trends by region, age groups, and fertility patterns. The Lancet , Volume 38. MyVarian Webinars – Hybrid-IMRT for Streamlining Breast Planning with Eclipse (Keith Nakonechny, Simcoe Muskoka Regional Cancer Centre) 15/12/2022

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Digital Poster Towards Consistency in Helical Tomotherapy: Insights from the first multi-centre comparative study Samuele Cavinato 1 , Stefano Agostinelli 2 , Paola Ceroni 1 , Elena Gallio 3 , Francesca Romana Giglioli 3 , Marta Paiusco 1 , Silvia Pesente 4 , Stefania Zara 4 , Daniele Zefiro 2 , Alessandro Scaggion 1 1 Medical Physics Department, Veneto Institute of Oncology IOV - IRCCS, Padova, Italy. 2 Medical Physics Department, IRCCS Ospedale Policlinico San Martino, Genova, Italy. 3 Medical Physics Unit, A.O.U. Città della Salute e della Scienza, Torino, Italy. 4 Research Unit, Tecnologie Avanzate, Torino, Italy Purpose/Objective: As part of a larger national initiative, we conducted the first multicentre intercomparison of Helical Tomotherapy treatment planning. This study aimed to compare treatment planning on clinical suitability, plan complexity, and plan specific QA (PSQA) outcomes. Material/Methods: The three participating centres shared the same delivery platform (Accuray RadixAct) and dosimetry equipment (SunNuclear ArcCheck) with similar PSQA practices, but used different TPSs. Radical Prostate and Head-and-Neck SIB (HN) were selected for the comparison. In a first retrospective phase, 30 historical treatments for each site were collected and analysed to establish baseline references for plan complexity and PSQA outcomes. In a subsequent prospective planning phase, five HN and five prostate common cases were planned and compared based on plan complexity metrics[1,2,3], PSQA outcomes, and Plan Quality Metric (PQM%) as clinical suitability surrogate.