S2722
RTT - Patient preparation, immobilisation, and verification protocols
ESTRO 2026
Material/Methods: STARE is a prospective, multicentre study with a paired-sample design (Date: July 9, 2024; Reference number: HCB/2024/0445). For each patient, SGRT and tattoo-based setups were alternated across consecutive treatment sessions, yielding paired data points for direct comparison. This design minimizes bias from anatomical changes during treatment (e.g., weight loss) and from variations in IGRT protocols, SGRT systems, clinical workflows, or RTT skills across centres. Online global IGRT corrections (3D shifts and rotations) were recorded for each fraction. Offline local IGRT corrections (which measure the residual 3D shifts and rotations that persist after applying online corrections) were also recorded (figure 1). These focus on critical anatomical regions for correct positioning: humerus and femur for breast/thorax and pelvis sites, respectively. This interim analysis provides a preliminary statistical comparison of global/local shifts/rotations and setup time, pending completion of paired-data recruitment.
reproducible setup, enhancing patient outcomes and quality of life. This offers a cost-effective, resource- efficient alternative to advanced radiotherapy technologies, suitable for centers with limited resources, improving accessibility and treatment efficacy. References: References:[1] Patel, R., et al. (2022). A Practical Approach to Total Body Irradiation (TBI) in Resource- Constrained Environments. Journal of Medical Physics, 47(3), 245-253.[2] Smith, J., et al. (2020). Total Body Irradiation: A Review of Techniques and Outcomes. International Journal of Radiation Oncology, Biology, Physics, 108(2), 341-353.[3] Johnson, L., et al. (2019). Dosimetric Comparison of VMAT-Based TBI and Conventional TBI Techniques. Journal of Applied Clinical Medical Physics, 20(6), 123-135.[5] American Association of Physicists in Medicine (AAPM). (2017). Total Body Irradiation: A Report of the AAPM Task Group 101. Medical Physics, 44(10), e555-e571. Keywords: HSCT, VMAT, Extended Technoque Preliminary results from STARE: prospective, multicentric, paired comparison of SGRT and tattoo-based setup accuracy Maria Salgado 1 , Lorena Díez-Presa 2 , David Navarro 2 , Irene Martínez 3 , Mario Martín 4 , Margarita Illas 5 , María Laplana 1 , Álvaro Martínez 1 , Artur Latorre-Musoll 1 1 Servei d'Oncologia Radioteràpica, Hospital Clínic de Barcelona, Barcelona, Spain. 2 Servei d'Oncologia Radioteràpica, Consorci Sanitari de Terrassa, Terrassa, Spain. 3 Servicio de Oncología Radioterápica, Hospital Universitario de Navarra, Pamplona, Spain. 4 Servicio de Radiofísica y Protección Radiológica, Hospital Universitario de Navarra, Pamplona, Spain. 5 Navarrabiomed, IdiSNA, Navarra Institute for Health Research, Pamplona, Spain Purpose/Objective: SGRT is a consolidated technique that enables non- invasive, full-body alignment and continuous monitoring during radiotherapy setup. However, previous comparisons with the traditional tattoo- based approach often rely on global displacement metrics, which may oversimplify positioning performance and underestimate SGRT’s potential to improve anatomical alignment. The Surface-guided radiation therapy versus Tattoo-based Approach: Reliability and Efficiency in patient positioning (STARE) study aims to provide a more comprehensive evaluation of SGRT versus tattoos by incorporating global, local, and rotational metrics, as well as setup time, to better capture clinically relevant differences. Poster Discussion 2133
Results: To date, 20 patients from 3 hospitals have been recruited. After excluding 2 withdrawals and extremities (only 2 patients for this site), 16 patients were analysed, yielding 348 individual fractions. Figure 2(a) shows SGRT reduced online global shifts by 0.12 ± 0.03 cm (p < 0.001) across all sites. Most notably, figure 2(b) shows mean humerus rotation in breast treatments was significantly reduced from 3.6° (0.3°–10.3°) with tattoos to 2.3° (0.1°–6.9°) with SGRT (5th–95th percentile) (p = 0.026). SGRT slightly increased treatment time by a non-significant 23 ± 16 s (p = 0.15). Remaining comparisons are still immature for statistical significance.
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