Physical phantoms with realistic anatomical texture and composition (including contrast media) are of high value and relevance in evaluating the performance of clinical computed tomography (CT) imaging systems. They can offer assessments of image quality in a manner that is more relevant than existing phantoms. The goal of this project was to fabricate anatomically structured 3-D liver texture with added contrast-enhancement. The study used an inkjet printer and customized ink. Patient-informed liver texture with contrast details was first defined computationally and the needed material for each tissue type was estimated for each voxel to produce attenuations from -200 to +300 HU, with subtle 5-20 HU lesions. Volumetric data were printed, one sheet of paper at a time, using “soft tissue” ink based on 200mg/cc sodium bromide (NaBr), and “enhanced tissue” ink based on Isovue-300. The phantom was scanned on a commercial CT system (Siemens SOMATOM Definition Flash) using a clinical protocol. The results show targeted heterogeneity and enhancement as designed with subtle artifacts associated with uneven air contamination. In ongoing work, we plan to use this method to create anatomically and morphologically accurate liver and lung lesions with texture for use in dual energy CT.
Anthropomorphic phantoms can serve as anatomically structured tools for assessing clinical computed tomography (CT) imaging systems. The aim of this project is to create highly customized 3D inkjet-printed, contrast-enhanced physical liver phantoms for use in improving CT imaging system analysis. The capability of using voxelized print to create physical phantoms with texture was previously presented by our lab. Building on that technology, we show the feasibility of producing iodine enhanced liver phantoms with varying textures, at resolutions higher than clinical CT using inkjetprinting. We use a desktop inkjet-printer, with custom inks to print these paper phantoms. Sodium bromide (NaBr) ink is used to represent unenhanced tissue, and potassium iodide (KI) represents contrast-enhanced tissue. We have shown the feasibility of using 3D inkjet-printing to create unique, contrast-enhanced liver phantoms for use in CT. In the future, we plan to expand our methods and tools to create tissue-equivalent physical phantoms for other anatomical structures in the abdominal region.
Custom 3D printed physical phantoms are desired for testing the limits of medical imaging, and for providing patientspecific information. This work focuses on the development of low-cost, open source fused filament fabrication for printing of physical phantoms with the structure and contrast of human anatomy in computed tomography (CT) images. Specifically, this paper introduces the concept of using a porous 3D printed layer as a background into which additional material can be printed to control the position-dependent contrast. By using this method, eight levels of contrast were printed with a single material.