ESTRO 2024 - Abstract Book

S182

Brachytherapy - GI, paediatric, miscellaneous

ESTRO 2024

2. Gerard J-P, Chapet O, Nemoz C, Hartweig J, Romestaing P, Coquard R, et al. Improved sphincter preservation in low rectal cancer with high-dose preoperative radiotherapy: the lyon R96-02 randomized trial. Journal of clinical oncology. 2004;22(12):2404-9. 3. Gerard JP, Barbet N, Schiappa R, Magné N, Martel I, Mineur L, et al. Neoadjuvant chemoradiotherapy with radiation dose escalation with contact x-ray brachytherapy boost or external beam radiotherapy boost for organ preservation in early cT2–cT3 rectal adenocarcinoma (OPERA): a phase 3, randomised controlled trial. The Lancet Gastroenterology and Hepatology. 2023;8(4):356-67. 4. Benezery K, Montagne L, Evesque L, Schiappa R, Hannoun-Levi JM, Francois E, et al. Clinical response assessment after contact X-Ray brachytherapy and chemoradiotherapy for organ preservation in rectal cancer T2 T3 M0: The time/dose factor influence. Clinical and Translational Radiation Oncology. 2020;24:92-8.

5. Dhadda AS, Martin A, Killeen S, Hunter IA. Organ Preservation Using Contact Radiotherapy for Early Rectal Cancer: Outcomes of Patients Treated at a Single Centre in the UK. Clinical Oncology. 2017;29(3):198-204.

1743

Proffered Paper

First clinical experiences: 3D-printed moulds for pediatric brachytherapy

Ida J.S. Kloosterman 1 , Petra S. Kroon 1 , Maarten H.G.J. Kastelijns 1 , Rutger R.G. Knops 2 , Weibel Braunius 3 , Francois J. Dieleman 3 , Emma C. Paes 4 , Peerooz Saeed 2,5 , Johannes H.M. Merks 2,6 , Raquel Dávila Fajardo 1,2 1 University Medical Center Utrecht, Department of Radiation Oncology, Utrecht, Netherlands. 2 Princess Máxima Center for Pediatric Oncology, -, Utrecht, Netherlands. 3 University Medical Center Utrecht, Department of Head and Neck Surgical Oncology, Utrecht, Netherlands. 4 University Medical Center Utrecht, Department of plastic and reconstructive surgery, Utrecht, Netherlands. 5 Academic Medical Center, Department of Ophthalmology, Amsterdam, Netherlands. 6 University Medical Center Utrecht, Division Imaging and Oncology, Utrecht, Netherlands

Purpose/Objective:

As a consequence of the Medical Device Regulations (MDR) some mould materials for individual applications are no longer usable. In this study, we describe the use of 3D printers to create an individualized 3D-printed mould for delivering pulsed dose rate brachytherapy (PDR) to pediatric patients. To our knowledge, this is the first time that 3D-printed moulds are used for this indication.

Material/Methods:

We retrospectively analyzed the pediatric brachytherapy treatments in our center where a 3D-printed mould was deployed from March 2021 to August 2023. We used PEEK (PolyEther Ether Ketone) in combination with the EXT 220 MED (Kumovis R1, 3D systems, United States) 3D printer and Biomed Clear in combination with the Formlabs 3B+ printer (Formlabs, United States). PEEK was used as an implant for a maximum of twelve days, Biomed Clear was used on skin or within the body cavity/mucous membrane for a maximum of twelve days. For both materials the MDR documentation was approved, which made it possible to continue running the AMORE treatment (Ablative surgery, MOuld technique for after loading brachytherapy, and surgical REconstruction) for head and