Novel radiopaque poly (lactic acid) filament production for phantom applications, and model studies for hard tissues

Purpose The complex geometries of human tissues are characterized by the employment of phantoms in various fields of medicine ranging from active treatment stages to educational purposes. Despite the exceptional abilities of the fused filament fabrication (FFF) technology to produce rapid and patient-specific complex anatomical models, the issue of human tissue-filament material incompatibilities persists owing to the lack of attenuation coefficients in the same range as biological tissues. The purpose of this study is to develop a novel biodegradable filament that can mimic human hard tissues by addressing the challenge mentioned above. Design/methodology/approach The current study addresses the issue through proposing a novel biodegradable radiopaque filament containing poly (lactic acid) (PLA) and antimony trioxide (Sb 2 O 3 ) with increasing amounts (3 wt%, 5 wt% and 10 wt%) for hard tissues. Other than the thermal/flow characterization and internal structural analyses, as for evaluating the effectiveness of the produced filament under computed tomography (CT) imaging, two detailed anthropomorphic phantoms (L3 vertebra and femur bone) are produced and tested. Findings Results show that Sb 2 O 3 disperse homogeneously and serve as a nucleating agent for PLA crystallization. Gyroid pattern gets very close isotropic structure with the highest hounsfield unit (HU) values. 5 wt% Sb 2 O 3 is required to get the HU values of cortical bone. The produced model hard tissues are in very compatible with patient images in all details including cortical thickness. Practical implications The results of this study will contribute to the development of radiopaque products in medical applications using three-dimensional printing. Originality/value The current research shows that inexpensive, patient-specific, detailed medical models can be produced with a novel biodegradable radiopaque filament containing PLA/Sb 2 O 3 . To the best of the authors’ knowledge, no study has examined the use of Sb 2 O 3 in radiopacity applications in any polymeric material.