Purpose: The role of additive manufacturing, or 3-dimensional (3D) printing, in medical physics is becoming increasingly useful because of the expanded opportunities for creating patient-specific customized treatment devices and in-house fabrication of dosimetry phantoms. The purpose of this study was to create a comprehensive physical characterization of various commercially available fused deposition 3D printing materials and explore their similarities to human tissues and other materials encountered in the radiation setting.
Methods: Thirteen different filaments were used to print uniform cylinders with infills ranging in50% to 100% at six evenly distributed intervals. Five filament materials contained high-Z/metallic components and eight were various less-dense materials. Three clinical CT scanners and a range of energy levels were used, including five kilovoltage (kV) energy levels (70kV, 80kV,100kV, 120kV, and 140kV) imaged on a Siemens machine and megavoltage (MV) energy levels on a Halcyon (6MV) machine. The images were analyzed using Mirada Medical where a cylindrical interior portion was used to find an average Hounsfield unit measurement for each print. A commercial phantom with GAMMEX inserts mimicking radiographic properties of various human tissues was also studied to use as a comparison with the tested materials.
Results: The HU versus energy was determined. The various materials and print settings produced a range of HU (-732.0–10047.4 HU) and physical densities (0.36-3.52g/cc) encompassing most tissues/materials encountered in radiology/radiotherapy applications. Many measured HU values overlapped with those of human tissues.
Conclusion: The study has compiled data characterizing commercially available 3D print materials to guide design of custom 3D printed objects for use in radiology/radiation oncology. This will allow for reduced cost and increased flexibility regarding fabrication of patient-specific devices or phantoms emulating various relevant materials for imaging and/or dosimetry purposes.