(155b) Achieving High Optical Translucency in SLA-Printed Elastic Materials for Patient-Specific Anatomical Models in Cardiovascular Medicine Applications

Stereolithographic (SLA) based additive manufacturing is one of the most popular methods to create complex polymer-based models thanks to the balance between cost and overall performance (resolution, speed, broad materials library, etc.). However, there are several important challenges that researchers have generally been trying to overcome, including 1) printing with soft materials, and 2) SLA-based fabrication of models with glass-like transparency. These obstacles need to be addressed to implement this method in areas like the fabrication of patient-specific anatomical models for applications in cardiovascular medicine, such as flow visualization phantoms, medical training and pre-procedural planning. Here, we present our work in the development of a post-processing method that enables the fabrication of high-accuracy elastic (compliant) models with close to glass-like transparency. We benchmark our final models against silicon-based commercial average-anatomy models in terms of optical transparency. We also show that our final multi-materials models have mechanical properties closer to human cardiovascular tissue than PDMS, which is one of the gold standards for flow visualization techniques. Through a comprehensive characterization we demonstrate how our proprietary formulations yield surfaces with sub-1 micron surface roughness and optical transmission values of up to 70% in hollow models. Furthermore, we show how we can integrate relatively small models into 1:1 scale full body anatomical models with our formulations. In summary, we have found a method to produce anatomical models of the cardiovascular system in elastic materials with high translucency without sacrificing in resolution or fidelity and without substantially increasing the cost. We hope that this contributes to the broader implementation of the technique in hospitals and medical schools.