Radiopaque 3D printing

Start date 01 November 2020

Uni Limerick

Client University of Limerick
Investigator

Dr David Nugent
david.nugent@elucidare.co.uk

 


Abstract

As 3D printing becomes accepted as a viable manufacturing technology, attention is shifting towards the development of new materials whose properties are optimised for specific applications. Nowhere is this trend more apparent than the medical sector, where resins are being developed to replicate the physical and tactile characteristics of biomaterials such as bones, soft tissues, etc. Such innovations propel additive manufacturing to a new level of realism and improved usefulness for teaching and planning complex surgery.

Conventional 3D printed resins are transparent to x-ray, however, making it difficult to discriminate between different regions when viewed by x-ray or CT scanner. This severely limits the usefulness of 3D printed phantoms for teaching radiography, and planning complex surgery involving in situ imaging such as angiography.

Researchers at the University of Limerick have invented a novel formulation of radiopaque resin and method for manufacturing articles using additive manufacturing. By blending a bioinert contrast pigment with standard PolyJet polymers, the team has demonstrated clear image contrast when viewed by standard x-ray and microCT.  Elucidare Limited is assisting with the commercialisation of this patent-pending technology and welcomes feedback from 3D printing specialist and healthcare professionals alike. 


Demonstration

An Objet Connex 500 multi-material 3D printer (Stratasys Ltd., USA) was used to print an STL hand model. Flesh regions were printed with TangoBlackPlus, a black rubber-like material when cured. Bones were printed using composite comprising zirconia (ZrO2) nanopower mixed with Biocompatible Clear MED610. Incorporation of zirconia increased the x-ray opacity from 800 Housfield Units (ZrO2=0wt%) to c.2,000 HU (ZrO2=20wt%).

As demonstrated in the microCT images shown below, excellent radiopacity was achieved in the 3D printed model. Here the bones were printed with ZrO2=5wt%.

 

 


Applications

We envisage this radiopaque ink will have an important role in 3D printing across the healthcare industry, from teaching radiography to visualising complex bone fractures and aneurisms. Furthermore, it can be incorporated into 3D printed medical devices to serve as fiducial markers during CT-guided surgery.

The video below illustrates how x-ray images will benefit from the radiopaque ink. In each case, the contrast of 3D printed models using standard resins are compared alongside those manufactured using the radiopaque ink. Unlike the microCT video shown above, the images shown below are STL animations, each illustrating the  advantages of radiopaque inks for visualising 3D printed models.

 

 

 


Further reading

More information on the patent-pending University of Limerick innovation can be obtained from the publications highlighted below.

 

Documents available for download

A radiopaque nanoparticle-based ink using PolyJet 3D printing for medical applications

PCT patent application - Priority date 07 Sept 2017
US Patent Application - Formulation for 3D Printing and a 3D printed article