Fused filament fabrication of complex anatomical phantoms with infill-tunable image contrast

Fused filament fabrication (FFF) provides a rapid means of producing anatomical models for biomedical education and training. However, FFF-compatible materials and methods are currently limited for efficient and accurate production of complex phantoms that can mimic the radiological properties of multiple human tissues. It is demonstrated in this research that the computed tomography (CT) contrast can be modified by varying the concentration of bismuth oxide in acrylonitrile butadiene styrene (ABS) filaments and by modifying the infill percentage of the printed models. By using an infill geometry consisting of an encapsulated pore structure, the CT contrast of fat, blood, kidney, liver, trabecular bone, and cortical bone could be successfully displayed without the presence of any artificial artefacts in the images. In addition, a lumbar spine phantom is printed with the infill varied throughout the model to accurately mimic the CT contrast for the trabecular and cortical bone volumes. This research is of particular relevance for FFF-printing of anatomical models for radiology education and imageguided surgical training.