S2707
RTT - Patient preparation, immobilisation, and verification protocols
ESTRO 2026
Conclusion: This novel technique has shown to be a viable application of LDRT for OA by integrating advanced 3D surface imaging and treatment planning technologies. It significantly improves efficiency, accuracy, reproducibility, and patient experience for localized OA in small joints. As accessibility to 3D scanning and 3D printing improves, this method may support wider adoption of LDRT in multidisciplinary management of treatment-resistant OA, with potential expansion to other benign inflammatory joint conditions5. References: 1. Salman LA, Ahmed G, Dakin SG, et al. Molecular approaches in OA management. Arthritis Res Ther. 2023;25:27. doi:10.1186/s13075-023-03006-w2. Steen K, Hayward V, Novak C, et al. Effects of hand radiotherapy. Hand (N Y). 2020;15(3):341–7. doi:10.1177/15589447188108913. Álvarez B, Montero A, Alonso R, et al. Low-dose RT for hand OA. Clin Transl Oncol. 2022;24(3):532–9. doi:10.1007/s12094-021- 02710-w4. Donaubauer AJ, Zhou JG, Ott OJ, et al. 0.5 Gy RT improves OA pain. Int J Mol Sci. 2020;21(16):5854. doi:10.3390/ijms211658545. Bochy ń ska A, Zawadzka A, Kuko ł owicz P, et al. 3D boluses in RT: review. Rep Pract Oncol Radiother. 2025;30(1):100–13. doi:10.5603/rpor.104014 Keywords: 3D Scanning Osteoarthritis Digital Poster Highlight 1359 Bladder preparation in prostate EBRT: A clinical, patient, and sustainability evaluation of standardised water bottles versus cups Jennifer O'Brien 1 , Sama Ahmed 1 , Prince Amoah-Kusi 1 , Elizabeth Davis 1 , Danielle Fairweather 1 , Nazima Haji 1 , John McMahon 1 , Selene Moore 1 , Yemurai Mundora 1 , Rita Simoes 1 , Amanda Webster 1,2 , William Kinnaird 1,2 1 Radiotherapy & Proton Beam Therapy, UCLH, London, United Kingdom. 2 Department of Medical Physics and Biomedical Engineering, UCL, London, United Kingdom Purpose/Objective: Bladder filling is used when preparing prostate cancer patients for radiotherapy (RT) to ensure reproducible bladder size and minimise treatment variation. At our institution, patients were previously instructed to drink five cups and wait 40 minutes before RT. However, variability in cup size/filling caused inconsistencies in bladder volume. This study evaluated whether introducing 800ml water bottles improved bladder size consistency, with secondary aims assessing patient understanding/satisfaction, and financial/environmental impacts. Material/Methods: A total of 40 prostate cancer patients having radical
reproducibility of this novel approach with conventional 3DCRT and electron techniques. Material/Methods: Ten patients were selected to undergo 3D surface scanning of the affected hand using a high-resolution optical scanner at initial consultation. An STL file was generated for the fabrication of a customized silicone bolus designed to eliminate air gaps, conform to anatomy, and improve stabilization.
After bolus fabrication, patients underwent a CT simulation with the bolus in place using a personalized Moldcare cushion for stabilization. A mix of supine and prone positions were utilized to maximize patient comfort. A VMAT plan was developed to enable highly conformal dose distributions around complex joint anatomy, minimizing exposure to surrounding tissues such as the fingernail bed and the thenar muscles2. Treatments were delivered in 6 fractions of 0.5–1.0 Gy over two weeks3,4. Image-guided radiotherapy (IGRT) using CBCT was employed for daily setup verification, with positioning adjusted using a 6DOF couch for sub- millimeter accuracy. Results: Of the ten patients selected 4 were treated for OA in their right hand and 6 were treated for OA in their left hand. The novel technique was compared to the existing approach of delivering treatment with a 3DCRT (AP/PA) or a single electron field using superflab bolus. The proposed novel technique demonstrated a high level of setup stabilization, reproducibility and extremely low inter-fraction variability. A comparison of dosimetric air gaps showed surface conformity of <0.3cm using the novel technique compared to <0.9cm with the use of superflab bolus in the traditional techniques. With improved stabilization, treatment delivery time was also reduced by approximately 17.4% and 10.1% compared to the electron and 3DCRT technique respectively.
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