S2723
RTT - Patient preparation, immobilisation, and verification protocols
ESTRO 2026
Radiological, Oncological and Pathological Sciences, Sapienza, Rome, Italy
Purpose/Objective: Adjuvant radiotherapy (RT) after breast-conserving surgery is essential in early-stage breast cancer, reducing local recurrence and improving survival [1–3]. Accurate patient positioning is crucial foroptimal target coverage and minimization of dose to organs of interest [4-6].Conventionaltattoo-based alignment, though effective, may cause psychological discomfort and aestheticconcerns [7]. Surface-guided RT (SGRT) offers a non-invasive alternative based on real-time optical surface imaging [8–10]. This study prospectively compared the accuracy andreproducibility of SGRT with traditional tattoo- based positioning in patients with right-sided early-
stage breastcancer. Material/Methods:
A single-center prospective crossover study was conducted including patients with right-sidedearly- stage breast cancer. Each patient served as their own control: tattoo-based positioning was used for thefirst fractions, followed by SGRT (AlignRT, Vision RT Ltd.) for the subsequent ones. All patientswere immobilized using the WingSTEP system and underwent free- breathing CT simulation (2 mmslice thickness). Treatment was delivered on a Versa HD linear accelerator with VMAT or 3Dconformal RT. Cone-beam CT (CBCT) was performed before each fraction to verify positioning.Translational and rotational setup variations were analyzed using paired two-sample t- tests. Results: In total 52 patients were enrolled.All patients completed RT, yielding 136 paired observations per technique. SGRT achievedsignificantly lower mean setup variations than tattoo-based positioning in the longitudinal (p = 0.001),vertical (p = 0.001), and lateral (p = 0.044) directions ( Fig 1). SGRT showed narrower variation distributionsand fewer outliers, whereas tattoo-based setups exhibited greater variability, with some translationaldeviations exceeding 1 cm. Fig.1
Conclusion: Preliminary STARE results indicate that SGRT outperforms tattoos in patient setup accuracy. While global shifts suggest SGRT superiority, its true value emerges in anatomical-dependent metrics, capturing rotations and non-rigid movements that persist despite online IGRT corrections and that SGRT can effectively reduce. Final analysis will confirm the
statistical significance of these insights. Keywords: SGRT, setup accuracy, IGRT
Digital Poster Highlight 2141 Breast cancer adjuvant radiotherapy without tattoos: comparison between surface imaging and four-point localization Chiara Lenci, Miriam Tomaciello, Silvia Arcieri, Martina Fantoni, Giusy Montalto, Rossella Caiazzo, AnnaLisa Magnante, Giuseppe Minniti, Francesca De Felice
Conclusion: SGRT demonstrated superior accuracy and reproducibility compared to traditional tattoo- basedalignment in right-sided early-stage breast cancer RT. Real-time surface tracking reduces systematic andrandom setup variations, improving target coverage and sparing of organs of interest. Moreover, eliminatingpermanent tattoos enhances patient comfort and satisfaction. These findings
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