Assessment and selection of filler compounds for radiopaque PolyJet multi-material 3D printing for use in clinical settings.

The aim of this research was to assess a selection of radiopaque filler compounds for increasing radiopacity in a resin suitable for Polyjet multi-material 3D printing. A radiopaque resin has potential applications in medicine to produce patient-specific anatomical models with realistic radiological properties, training aids, and skin contacting components such as surgical or procedural guides that require visibility under fluoroscopy. The desirable filler would have a high level of radiopacity under ionising imaging modalities, such as X-ray, CT, fluoroscopy or angiography. Nine potential filler compounds were selected based on atomic number and handling risk: barium sulphate, bismuth oxide, zirconium oxide, strontium oxide, strontium fluoride, strontium carbonate, iodine, niobium oxide and tantalum oxide. The fillers were evaluated using selected criteria. A weighted material selection matrix was developed to prioritise and select a filler for future 3D printing on a multi-material 3D printer. Zirconium oxide was the highest scoring filler compound in the material selection matrix, scoring 4.4 out of a maximum of 5. MED610TM resin doped with zirconium oxide was shown to be UV curable, and when cured is non-toxic, environmentally friendly, and has the ability to display antimicrobial properties. In terms of radiopacity, a sample with thickness 1.5 mm of MED610™ resin doped with 20 wt.% zirconium oxide produced X-ray radiopacity equivalent to 3 mm of aluminium. Zirconium oxide was selected using the material selection matrix. This radiopaque resin can be used to produce anatomical models with accurate radiological properties, training aids or skin contacting devices that require visibility under ionising imaging modalities. The 3D printing validation run successfully demonstrated that the material selection matrix prioritised a filler suitable for radiopaque multi-material 3D printing.

A Radiopaque Nanoparticle-Based Ink Using PolyJet 3D Printing for Medical Applications.

The aim of this study was to develop a 3D printable radiopaque ink and successfully print a finished artifact. Radiopaque 3D printing would be hugely beneficial to improve the visibility of medical devices and implants, as well as allowing more realistic phantoms and calibration aids to be produced. Most 3D printing technologies are polymer based. Polymers are naturally radiolucent, allowing X-rays to pass through, showing up as faint dark gray regions on X-ray detectors, as for soft tissues. During this study, a 3D printable ultraviolet (UV) curable resin containing zirconium oxide (ZrO2) nanoparticles was developed. 5 wt.% ZrO2 was dispersed in a base resin using a high-shear mixer. Particles remained in suspension for 6-8 h at room temperature, allowing time for 3D printing. A model of a hand including radiopaque bones and a test block demonstrating a range of internal radiopaque features were successfully 3D printed. Radiopacity was demonstrated in the 3D-printed models, and there was good dispersion of ZrO2 within the resin matrix. The impregnated resin remained UV curable and viscosity was not compromised. In this study, 3D-printed radiopaque features demonstrated clear radiopacity under X-ray and microcomputed tomography imaging.