2026/01/14
Radiopaque filaments for fused filament fabrication (FFF) 3D printing
Zekraoui, S.; Lescot, T.; Akbari Taemeh, M.; Fortin, M.A. (2025). Radiopaque filaments for fused filament fabrication (FFF) 3D printing. Additive Manufacturing, vol. 110, 2025, 104914.
Polyetheretherketone (PEEK) is a chemically resistant, high-performance polymer known for its excellent thermal and mechanical properties. It is increasingly employed in the development of 3D-printed medical implants and radiotherapeutic devices. While PEEK exhibits strong resistance to radiation-induced degradation, it has inherently poor radiation-blocking capacity. However, many tools and components used in radiology, radiotherapy, and nuclear medicine—such as brachytherapy implants, shielding devices, imaging screens, and personalized radioprotective equipment—require a certain degree of radiopacity. This study presents a novel methodology for integrating electron-dense particles (micro- or nanosized) into high-performance polymer filaments suitable for fused filament fabrication (FFF) 3D printing. Specifically, a new pre-processing approach was developed to achieve optimal mixing of micrometer-sized tungsten (µW) particles with micrometer-sized PEEK particles (µPEEK), prior to their incorporation into millimeter-sized PEEK pellets. This tri-phased particle mixture enabled high-temperature extrusion, producing robust, continuous filaments with uniformly embedded metal particles within a protective polymer matrix. The resulting filaments were characterized using scanning electron microscopy (SEM) to assess morphology, X-ray fluorescence (XRF) imaging to evaluate particle distribution homogeneity, and elemental analysis to quantify the content of the radiation-blocking material. Filaments containing tungsten at concentrations below 10 vol.% were used to fabricate high-density, 3D-printed structures of varying thicknesses. Optimal printing parameters were identified, and the X-ray attenuation properties of the printed objects were evaluated through radiographic imaging. Additionally, mechanical properties of the 3D-printed PEEK, and PEEK-W composites were evaluated through standardized flexural and Vickers hardness testing. Finally, biocompatibility testing using primary human choroidal fibroblasts (hCSF) cells demonstrated high cell viability after four days of exposure to the W-loaded PEEK prints. These findings highlight the potential of 3D-printed radiopaque polymers not only for medical implants but also for applications in aerospace and nuclear technology.