Additively Manufactured Patient-Specific Anthropomorphic Thorax Phantom With Realistic Radiation Attenuation Properties

Sepideh Hatamikia; Gunpreet Oberoi; Ewald Unger; Gernot Kronreif; Joachim Kettenbach; Martin Buschmann; Michael Figl; Barbara Knäusl; Francesco Moscato; Wolfgang Birkfellner

doi:10.3389/fbioe.2020.00385

Additively Manufactured Patient-Specific Anthropomorphic Thorax Phantom With Realistic Radiation Attenuation Properties

Front Bioeng Biotechnol. 2020 May 8:8:385. doi: 10.3389/fbioe.2020.00385. eCollection 2020.

Authors

Affiliations

¹ Austrian Center for Medical Innovation and Technology, Wiener Neustadt, Austria.
² Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.
³ Institute of Diagnostic, Interventional Radiology and Nuclear Medicine, Landesklinikum Wiener Neustadt, Wiener Neustadt, Austria.
⁴ Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria.
⁵ Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria.

Abstract

Conventional medical imaging phantoms are limited by simplified geometry and radiographic skeletal homogeneity, which confines their usability for image quality assessment and radiation dosimetry. These challenges can be addressed by additive manufacturing technology, colloquially called 3D printing, which provides accurate anatomical replication and flexibility in material manipulation. In this study, we used Computed Tomography (CT)-based modified PolyJet^TM 3D printing technology to print a hollow thorax phantom simulating skeletal morphology of the patient. To achieve realistic heterogenous skeletal radiation attenuation, we developed a novel radiopaque amalgamate constituting of epoxy, polypropylene and bone meal powder in twelve different ratios. We performed CT analysis for quantification of material radiodensity (in Hounsfield Units, HU) and for identification of specific compositions corresponding to the various skeletal structures in the thorax. We filled the skeletal structures with their respective radiopaque amalgamates. The phantom and isolated 3D printed rib specimens were rescanned by CT for reproducibility tests regarding verification of radiodensity and geometry. Our results showed that structural densities in the range of 42-705HU could be achieved. The radiodensity of the reconstructed phantom was comparable to the three skeletal structures investigated in a real patient thorax CT: ribs, ventral vertebral body and dorsal vertebral body. Reproducibility tests based on physical dimensional comparison between the patient and phantom CT-based segmentation displayed 97% of overlap in the range of 0.00-4.57 mm embracing the anatomical accuracy. Thus, the additively manufactured anthropomorphic thorax phantom opens new vistas for imaging- and radiation-based patient care in precision medicine.

Keywords: 3D printed thorax; additive manufacturing; computed tomography (CT) imaging; patient-specific phantom; precision medicine; radiation attenuation.