Purpose or Case Report: Additive manufacturing (also called 3D printing and rapid prototyping) in medical research and clinical applications is expanding. This study aims to quantify the imaging characteristics (Ultrasound, Magnetic Resonance Imaging, and Computed Tomography scan) of available materials on a common additive manufacturing technology and discuss potential opportunities to fabricate imaging phantoms, which can be utilized in:
-Training residents and technologists on the equipment and techniques
-Practice for unique case studies and interventions
-Planning procedures for complex surgical and interventional cases
-Quality assurance of equipment for safety
These would be high accuracy and cost-effective models, providing significant savings for purchased phantoms, which can cost over $3k. Moreover, printed phantoms allow custom phantoms for specific applications or anatomy unique to specific patient beyond pre-fabricated options.
Methods & Materials: A material sample phantom was fabricated by embedding printed materials and blends into silicon. Technologists scanned the material phantom using 3 scanning modalities (Ultrasound, Magnetic Resonance Imaging, and Computed Tomography). The images were then evaluated for echogenicity, relaxation, and radiodensity, respectively. Dimensional accuracy of the printed phantoms was also evaluated.
Results: Ultrasound phantom scanning produced clearly defined edges of the material but did not provide a range of different echogenicities. MRI scanning showed distinct signal intensity between model (14.7 grayscale value) and printer support (789.33 grayscale value), but no distinguishing signal between different print materials. CT scans showed variation in plastic and rubber materials between 93 to 160 Hounsfield units. Dimensional measurements confirmed the accuracy of printed phantoms to the original design.
Conclusions: The imaging properties of additive manufacturing offer an opportunity to create simple phantoms applicable. These materials cannot currently be extended to complex multi-material application as realistic as the imaging properties of human tissue. However, in this developing field, we anticipate new density varied materials that will better approximate the imaging characteristics of the anatomy. Particularly promising are the ongoing studies into composites and fiber laced materials. This report supports the potential of additive manufacturing to create simple, accurate, and cost-effective imaging phantoms, which could expand with further material research.