ESTRO 2024 - Abstract Book

S205

Brachytherapy - General

ESTRO 2024

Tungsten (W)-containing PEEK filaments (more than 2 m long; 1.75 in diameter) presenting W concentrations superior to 5% v/v, were efficiently extruded, and enrolled on a mandrel. The particle size and the homogeneity of W distribution within these filaments, were revealed by SEM and XRF. Coupons of various thicknesses (0.1 – 1.5 mm) were successfully 3D printed by FFF, and their X-ray blocking capacity was measured by mCT imaging (80 kVp, W anode) (Figure 1A-C). Signal intensity and X-ray attenuation curves were plotted and confirmed the blocking capacity of thus-formed 3D-printed objects (Figure 1D,E), and the attenuation coefficients were in agreement with the volume percentage of W distributed in the PEEK polymer. Finally, the FFF 3D printing strategy developed allowed the fabrication of EP of sizes and dimensions representative of that prescribed by the standard Collaborative Ocular Melanoma Study (COMS) protocol. 2 (Figure1 F, G). The W-containing 3D-printed plaques (Figure 1G) allowed an efficient and precise drilling of millimetric-sized cavities required for the deposition and sealing of radioactive 125 I (Figure 1, H,I).

Conclusion:

This work confirms the possibility to 3D print radiopaque polymer parts made of mechanically and chemically resistant material (PEEK) and opens the possibility to fabricate with this versatile technology, a variety of implants, inserts, and devices for brachytherapy. Current studies in the laboratory address the possibility to replace radioactive seeds by addition of radioactive drops of 125 I, followed by adequate sealing. The use of a 3D printable radiopaque polymer, coupled to a more flexible and precise means of adding radioactivity to brachytherapy plaques, could expand the possibilities for more personalised brachytherapy implants of enhanced precision in terms of dose distribution.

Keywords: 3D printing, radiopaque materials, implants

References:

1 Lescot T, Fortin MA, et al, “Tumor Shape-Specific Brachytherapy Implants by 3D-Printing, Precision Radioactivity Painting, and Biomedical Imaging”; Advanced Healthcare Materials (Wiley), 03 August 2023.