A new test method to assess the representation of spiculated mass like targets in digital mammography and breast tomosynthesis

In this work we tested different materials for 3D printing of spiculated mass models for their incorporation into an existing 3D structured phantom for performance testing of FFDM and DBT. Counting the number of spicules as a function of dose was then evaluated as a possible extra test feature expressing conspicuity next to detectability. Seven printable materials were exposed together with a PMMA step wedge and material samples with known linear attenuation coefficient to determine PMMA equivalent thickness and linear attenuation coefficient, respectively. Next, two models of spiculated masses were created each with a different complexity in terms of number of spicules. The visibility of the number of spicules of a 3D printed spiculated mass model loosely placed in the phantom or embedded into two different printing materials was assessed for FFDM and DBT. Vero White pure was chosen as the most appropriate material for the printing of masses whereas Vero Clear and Tango+ were chosen as background materials. The visibility of spicules was best in the loose mass models and better in the background material Tango+ compared to Vero Clear. While the discrimination of the different spicules could be assessed in FFDM and DBT, as expected only a limited dose sensitivity was found for the visibility of spicules evaluated for the different background materials and at different beam energies.