TU‐H‐CAMPUS‐IeP2‐05: Breast and Soft Tissue‐Equivalent 3D Printed Phantoms for Imaging and Dosimetry

Abstract

Purpose:The study has the goal to demonstrate that breast and soft tissue‐equivalent phantoms for dosimetry applications in the diagnostic energy range can be fabricated using common 3D printing methods.Methods:3D printing provides the opportunity to rapidly prototype uniquely designed objects from a variety of materials. Common 3D printers are usually limited to printing objects based on thermoplastic materials such as PLA, or ABS. The most commonly available plastic is PLA, which has a density significantly greater than soft tissue. We utilized a popular 3D printer to demonstrate that tissue specific phantom materials can be generated through the careful selection of 3D printing parameters. A series of stepwedges were designed and printed using a Makerbot Replicator2 3D printing system. The print file provides custom adjustment of the infill density, orientation and position of the object on the printer stage, selection of infill patterns, and other control parameters. The x‐ray attenuation and uniformity of fabricated phantoms were evaluated and compared to common tissue‐equivalent phantom materials, acrylic and BR12. X‐ray exposure measurements were made using narrow beam geometry on a clinical mammography unit at 28 kVp on the series of phantoms. The 3D printed phantoms were imaged at 28 kVp to visualize the internal structure and uniformity in different planes of the phantoms.Results:By utilizing specific in‐fill density and patterns we are able to produce a phantom closely matching the attenuation characteristics of BR12 at 28 kVp. The in‐fill patterns used are heterogeneous, so a judicious selection of fill pattern and the orientation of the fill pattern must be made in order to obtain homogenous attenuation along the intended direction of beam propagation.Conclusions:By careful manipulation of the printing parameters, breast and soft tissue‐equivalent phantoms appropriate for use at imaging energies can be fabricated using 3D printing techniques.