Phantoms; 3d printing; radiography; computed tomography; additive manufacturing
en
Abstract:
3D printing offers fascinating possibilities for the production of X-ray phantoms for general (projective) radiography up to CT applications. While in 2D phantoms different attenuations can be realized by different absorption lengths, CT phantoms require materials with different mass density and/or different effective atomic number. In FDM (fused deposition modeling) printing, mass density depends on packing density of solid structures. Common printing parameters, however, result in filling ratios < 100%, and thus lower density negatively affecting reproducibility of phantoms, x-ray attenuation and Hounsfield Units in CT, and thus contrasts. As a consequence, printing parameters need to be optimized and controlled to result in maximum solid density. In SLA (Stereolithography) printing parameters do not influence density, and can only be set manually in one of the printers used (Anycubic Photon). In this project 41 kinds of materials consisting of filaments and resins were printed with different kinds of printers (Utimaker2+, Anycubic Photon, Formlabs Form 2 and Connex3). The optimal printing parameters for optimal printing quality and optimal filling ratio of 29 kinds of materials for FDM printer were measured respectively. An X-ray phantom was designed and printed out, and it was used for measuring Hounsfield Units (HU) of 41 kinds of materials by CT scanning.Materials most suitable for mimicking soft tissues and bone in radiographic phantoms could be identified.