MO-F-CAMPUS-I-03: CT and MR Characteristics of Some Specialty 3D Printing Filaments




To quantify the Hounsfield Unit and demonstrate MR signal of specialty 3D printer filaments that are recently made available to fused deposition modeling (FDM) 3D printers as raw materials to print 3D objects such as phantoms and patient specific boluses or shields.


We acquired 2.85mm diameter batches of ColorFabb copperfill metal filament, Soft PLA filaments of different colors (Red, Blue, White, Beige, Black), BendLay filament, Taulman Bridge filament, NinjaFlex water semi-transparent thermoplastic elastomer filament, Light Cherry Wood LAYWOO-D3 filament, as well as the more commonly used polylactic acid (PLA) filament and acrylonitrile butadiene styrene (ABS) filament. We also included 2.5mm diameter silicone, polyurethane, neoprene, and nitrile rubber (soft Buna-N) o-ring cords for comparison. These filaments were arranged in a 4×4 array in a 5cm × 15cm × 15cm block of UHMW polyethylene. CT scan of 1mm slice thickness was performed with a cranial SRS protocol. MR scan was performed with an ultra-short echo time point-wise encoding time reduction with radial acquisition (UTE PETRA) protocol in a water bath. The CT and MR of these different materials were imported into Eclipse. In order to reduce the contribution of partial volume effect, the maximum HU of each material were determined in 4 slices and averaged.


The copperfill filament HU was saturated at 2975. Soft PLA filaments had HU in the range of 400–500. PLA and NinjaFlex were 100–200 HU. Taulman Bridge filament was about 63 HU. LAYWOO- D3, ABS, and BendLay filaments were between −60 to −30 HU. Overall, the HU of these specialty filaments spanned the range from −60 to >3000. The materials were also visible in the UTE MR image.


The wide range of materials available to FDM 3D printing made possible the fabrication of various objects for medical physics to emulate different tissues.