ESTRO 2025 - Abstract Book

S2740

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

ESTRO 2025

EClinicalMedicine. 2022;47. 2. Chopra S, Gupta S, Kannan S, Dora T, Engineer R, Mangaj A, et al. Late Toxicity After Adjuvant Conventional Radiation Versus Image-Guided Intensity-Modulated Radiotherapy for Cervical Cancer (PARCER): A Randomized Controlled Trial. J Clin Oncol. 2021;39:3682-3692.

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Digital Poster Improving efficiency and standardisation in simple 2-field breast planning Alexandra C peacock 1 , Ruben Farias 2 1 Service Improvement, Genesis Care UK, Bristol, United Kingdom. 2 Physics, Genesis Care UK, Chelmsford, United Kingdom Purpose/Objective: Breast cancer rates are rising, with the highest incidence in women <50 years (Lima SM, 2021). At GenesisCare UK, breast planning accounted for 45% of the workload in 2022 (63% IMRT to the breast/chest wall using Eclipse TPS (v15.6)). Due to the predicted rise in cases, it is imperative the process for planning tangential breast treatment is streamlined and automated. In response, we revised our approach to 2-field breast planning, from Dynamic IMRT to scripted hybrid planning, following the technique from MyVarian (Nakonechny K 2022). This study will audit and assess the changes in the planning process to measure improvements in efficiency, consistency, and quality. Material/Methods: 29 patients receiving 26Gy in 5 fractions (as per Fast Forward trial), were analysed (13 dIMRT, 16 scripted hybrid). All plans were created in Eclipse V15.6. The following criteria were assessed: • Target (TV) coverage: V95%, V100%, V107%, dMax, conformity indices (CI) (RTOG and Paddick), homogeneity index (HI) and gradient index (GI) • OAR constraints: heart, contralateral lung, ipsilateral lung, contralateral breast • ProKnow plan score: summation of PTV coverage, OAR dose and quality indicators • Mean planning time Results: The mean planning time reduced from 2 hours (dIMRT), 45 mins (hybrid) to less than 20 mins with scripting. With a single optimisation, planning time from field placement can be <10 mins. The Clinician contouring time reduced from 20 mins to <5 mins.

There was an overall reduction in OAR doses. Mean doses to the heart, contralateral breast and both lungs are outlined in Figure 1.

Figure 1 - mean OAR dose constraints for dIMRT and hybrid plans