A New Breast Phantom With a Durable Skin Layer for Microwave Breast Imaging

Breast phantoms (BPs) are required to test and validate microwave breast imaging prototypes. For this purpose, a new BP made from carbon/rubber mixtures is proposed. These materials have: 1) electrical properties that are stable over time and representative of human target values and 2) mechanical properties that allow the material to be flexible and withstand reasonable stress. To characterize and optimize the carbon/rubber materials, samples made with varying carbon concentrations were created and the dielectric properties were measured. From these materials, a skin layer, fatty layer, glandular structures, and phantom tumors were cast from three-dimensional (3-D) printed molds and assembled into a complete BP. These phantoms mimic the anatomical structures of the breast, are reconfigurable for a variety of tests, and are easy to create in a typical lab environment. A microwave breast imaging prototype system was used to measure reflections from BPs. Comparison with reflections from human trials demonstrated that the phantom provides appropriate skin reflections. Phantoms incorporating glandular structures were imaged using a delay-and-sum technique. A response consistent with the position of the inclusions was observed. Overall, the carbon-based phantoms provide similar reflections to human tissue, and have proven useful for testing our imaging algorithms.