S2021
Physics - Dose prediction/calculation, optimisation and applications for photon and electron planning
ESTRO 2026
previously been treated for follicular lymphoma. On July 1, 2025, the patient was evaluated for bone marrow transplantation. On October 23, 2025, the patient was evaluated for TBI and TSI in the Radiotherapy Department at USK nr 1 in Lublin. Prescription dose was 12Gy in hyperfractionation twice a day per 2Gy. Two data sets were performed in supine position using a large, whole body vacuum cushion and thermoplastic mask: head head-first scan (HFS) and feet-first (FFS), with a common area covering markers placed on the pelvis. A 5mm thick neoprene suit and 3mm neoprene gloves and socks were used. The PTV was designated as a TSI 5mm into subcutaneous tissue and TBI the rest of body without TSI. The treatment plan was performed in TPS Monaco 5 witch the VMAT technique with 10 isocenters, 6MV energy, using the Base Dose Plan option. Fluence extension was performed over the whole body. Portal dosimetry was done, and patient positioning was checked using CBCT for each isocenter. Results:
and found to correlate with the 70% isodose. Cardiac dose analysis under DIBH confirmed compliance with constraints (V7Gy < 5%, V1.5Gy < 25%). Validation of the tool accurately stratified patients by left-lung V8Gy, clearly identifying candidates for the protocol and flagging cases around the 20% V8Gy threshold (i.e., V8Gy ≤ 20%). LuLI showed a monotonic relationship with V8Gy and supported a three-tier pathway: clear eligibility, borderline cases prompting detailed DVH review, and non-eligibility. The model reduced the need for trial plans and focused planner effort on ambiguous cases, while DIBH maintained cardiac doses within accepted limits. Conclusion: A simple hemi-ellipsoidal geometric model, used together with the LuLI index, can serve as a rapid and practical decision-support tool for selecting patients for the FAST-Forward protocol. Its application may reduce the need for trial plans, improve planning efficiency, and facilitate early identification of cases in which the risk of delivering an excessive lung dose exceeds tolerance thresholds. References: * Brunt AM, Haviland JS, Wheatley DA, et al. Hypofractionated breast radiotherapy for 1 week versus 3 weeks (FAST-Forward): 5-year efficacy and late normal tissue effects results from a multicentre, non-inferiority, randomised, phase 3 trial. Lancet. 2020;395(10237):1613–1626. Keywords: breast cancer, DIBH, hybrid technique (3DCRT+VMAT) Digital Poster 5047 Simultaneous Total Body and Total Skin Irradiation (TBI/TSI): A novel combined approach. Maria Piziorska 1,2 , Aleksandra Koz ł owska 1,3 1 Radiotherapy Department, University Clinical Hospital No.1 in Lublin, Lublin, Poland. 2 Radiotherapy Department, St. Luke's Provincial Hospital in Tarnów, Tarnów, Poland. 3 Radiotherapy Clinic, Medical University of Lublin, Lublin, Poland
The results (TABLE1) showed target coverage to be maintained at the acceptable level while sparing the organs of interest in accordance with the protocol in force at the center. The 5mm neoprene suit used allowed for an increase in 90% isodose coverage PTV TSI by 11% in the while 95% and 100% isodose coverage increased by 13.57% and 7.62%, respectively (FIGURE1).
Purpose/Objective: Currently, the standard technique for skin irradiiation (TSI) radiotherapy is electrons. An
alternative treatment is helical tomotherapy (TTSI), while all body (TBI) treatment is mainly performed using VMAT or tomotherapy. The solution we propose allows for irradiation of the TBI with simultaneous irradiation of the TSI using conventional accelerator with the VMAT technique with a neoprene suit as a bolus. Material/Methods: A 51-year-old patient was diagnosed with peripheral T- cell lymphoma requiring skin irradiation. He had
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