Introduction of a Novel Technique in Density-Adjusted 3D Printing for the Manufacture of Soft-Tissue-Equivalent Radiological Phantoms

The aim of this study is to introduce a new filament and novel 3D printing technique toadjust the density of a printing job in order to mimic the radiological properties of different tissues. Weused a special filament, LightWeight PLA (LW-PLA), which utilizes foaming technology triggered bytemperature. Cylindrical samples were printed at various temperatures, flow rates, print speeds, anddiameters. A computed tomography (CT) scan was performed to identify their radiological propertiesin terms of the mean Hounsfield Unit (HU). The densities of the samples ranged from 0.36 g/cm3to 1.21 g/cm3, corresponding to mean HU values between −702.7 ± 13.9 HU and +141.4 ± 7.1 HU.Strong linear correlations were observed between the flow rate and density as well as the flow rateand mean HU. The axial homogeneity of the samples was reported as being comparable to that ofdistilled water. A reduction in the mean HU was observed at a lower print speed and it changedslightly with respect to the sample size. Reproducibility assessments confirmed consistent results foridentical printing jobs. Comparisons with regular PLA samples revealed a superior homogeneityin the LW-PLA samples. The findings of this study suggest a practical and accessible solution formimicking all of the soft tissues, including the lungs, by using a single filament.