ESTRO 2025 - Abstract Book

S4102

RTT - Patient care, preparation, immobilisation and IGRT verification protocols

ESTRO 2025

Conclusion: Our results show when using an ATS strategy in case of OAR deformations only, does not significantly improve OAR dose and therefore using the more efficient ATP workflow could also be appropriate.

Keywords: online adaptive, MR-linac, MRlinac, SBRT prostate

References: 1. Dassen M.G, Janssen T, Bijl vd E et al Comparing adaptation strategies in MRI-guided online adaptive radiotherapy for prostate cancer: Implications for treatment margins. Radiotherapy and Oncology 186 (2023) 109761

2854

Proffered Paper A novel approach to palliative radiation therapy: results from the SIM(simulation)-FREE pilot study Andrea Lastrucci 1,2 , Pietro Donatini 1,2 , Giulio Rossi 1,2 , Elisabetta Martini 1,2 , Monica Morroni 1,2 , Sara Tagliasacchi 1,2 , Letizia Scaglione 1,2 , Elisa Moabiti 1,2 , Elisa Consumi 1,2 , Neda Haghighatjou 1,2 , Gabriele Simontacchi 2 , Daniela Greto 2 , Mauro Loi 2 , Pietro Garlatti 2 , Yannick Wandael 1 , Renzo Ricci 1 , Lorenzo Livi 3 1 Department of Allied Health Professions, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy. 2 Radiation Oncology Unit, Azienda Ospedaliero-Universitaria Careggi, Florence, Italy. 3 Department of Experimental and Clinical Biomedical Sciences "M. Serio", University of Florence, Florence, Italy Purpose/Objective: Palliative Radiotherapy (RT) plays a crucial role in pain relief and quality of life improvement in symptomatic metastasis . The reduction of hospital access could be essential in symptomatic and fragile patients. The SIM FREE single-center pilot study aims to assess the feasibility of an innovative workflow designed to optimize palliative RT. Material/Methods: The SIM FREE study introduces an entirely new workflow that allows the diagnostic CT (dCT) to be used for treatment planning in place of a planning CT (pCT). This pilot study enrolls patients with vertebral and iliac metastases eligible for a single fraction RT. Since no pCT is performed, the patient positioning is tattoo-less and the Surface Guided Radiation Therapy (SGRT) technology is obtained allowing real-time comparison of the patient's surface position to a reference image derived from the dCT data. Additionally, a Cone Beam Computed Tomography (CBCT) scan is performed and registered with the dCT to correct any rotational or translational shifts. Adjustments are then performed using a Six Degrees of Freedom (6DoF) couch to optimize the patient's positioning for treatment. Data were systematically collected on key parameters, including the total pathway time (from initial consultation to treatment delivery), overall treatment time (from patient positioning to radiation administration), and setup shifts for each patient.