ESTRO 2025 - Abstract Book

S1426

Clinical - Lung

ESTRO 2025

Figure 1: Treatment plan of 40Gy in 5 fractions including BgRT for a lung tumor (left) and SBRT for a kidney tumor (right) in a single plan

Results: The MTT delivery was successful and conformal (Figure 2). On synthetic PET imaging created using diagnostic PET data, the lung tumor had an activity concentration (AC) 14.1 kBq/ml and a normalized target signal (NTS) 14.6, meeting BgRT criteria: AC ≥5 kBq/ml and NTS ≥2.7. It subsequently met these criteria on the functional PET modeling scan. The FDG dose remained within a 2% uncertainty margin across all fractions. The uptake time was 60±3 minutes for all fractions, AC stayed ≥15 kBq/ml, and NTS stayed ≥7 despite lung tumor shrinkage. Target coverage remained 100% within the bounded dose-volume histogram parameters and all dose constraints to OARs were met. Mean delivery time per fraction was 36 min 9 sec for BgRT and 16 min 8 sec for SBRT.

Figure 2 : Lung tumor visualized on functional PET modeling (left) and BgRT plan (dotted lines) and delivery (dashed lines) (right)

Conclusion: This case demonstrates the feasibility and reliability of combining BgRT and SBRT in a single plan for MTT. It marks a significant milestone, offering a customizable approach for various tumor locations, especially as BgRT indications for use expand.

Keywords: First-in-Human, Biology-guided Radiotherapy, SBRT

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Digital Poster Cardiac substructures’ dose in stage III NSCLC pts undergoing chemoradio-immunotherapy: retrospective monocentric analysis of acute and late toxicity Anna Cappelli 1 , Francesca Di Pressa 1 , Giorgia Guaitoli 2 , Jessica Imbrescia 1 , Federica Bertolini 2 , anna Benini 1 , Nicola Maffei 3 , Gabriele Guidi 3 , Patrizia Giacobazzi 1 , Alessio Bruni 1 1 Radiotherapy Unit, Department of Oncology and Hematology, Modena University Hospital, Modena, Italy. 2 Division of Oncology, Department of Oncology and Hematology, Modena University Hospital, Modena, Italy. 3 Medical Physics Unit, Modena University Hospital, Modena, Italy