A physical breast phantom for 2D and 3D x-ray imaging made through inkjet printing

Physical breast phantoms are used for imaging evaluation studies with 2D and 3D breast x-ray systems, serving as surrogates for human patients. However, there is a presently a limited selection of available phantoms that are realistic, in terms of containing the complex tissue architecture of the human breast. In addition, not all phantoms can be successfully utilized for both 2D and 3D breast imaging. Additionally, many of the phantoms are uniform or unrealistic in appearance, expensive, or difficult to obtain. The purpose of this work was to develop a new method to generate realistic physical breast phantoms using easy to obtain and inexpensive materials. First, analytical modeling was used to design a virtual model, which was then compressed using finite element modeling. Next, the physical phantom was realized through inkjet printing with a standard inkjet printer using parchment paper and specialized inks, formulated using silver nanoparticles and a bismuth salt. The printed phantom sheets were then aligned and held together using a custom designed support plate made of PMMA, and imaged on clinical FFDM and DBT systems. Objects of interest were also placed within the phantom to simulate microcalcifications, pathologies that often occur in the breast. The linear attenuation coefficients of the inks and parchment were compared against tissue equivalent samples and found to be similar to breast tissue. The phantom is promising for use in imaging studies and developing QC protocols.