Silicone breast phantoms for elastographic imaging evaluation
Purpose: Breast cancer is a major public health issue for women, and early detection significantly increases survival rate. Currently, there is increased research interest in elastographic soft-tissue imaging techniques based on the correlation between pathology and mechanical stiffness. Anthropomorphic breast phantoms are critical for in-vitro validation of emerging elastographic technologies. This research develops heterogeneous breast phantoms for use in testing elastographic imaging modalities. Methods: Mechanical property estimation of eight different elastomers is performed to determine storage moduli (E’) and damping ratios (ζ) using a dynamic mechanical analyzer (DMA). Dynamic compression testing was carried out isothermally at room temperature over a range of 4-50 Hz. Silicone compositions with physiologically realistic storage modulus were chosen for mimicking skin adipose, cancerous tumors and pectoral muscles and 13 anthropomorphic breast phantoms were constructed for in vitro trials of Digital Image Elasto Tomography (DIET) breast cancer screening system. A simpler fabrication was used to assess the possibility of multiple tumor detection using Magnetic Resonance Elastography (MRE). Results: Silicone materials with ranges of storage moduli (E’) from 2 to 570 kPa and damping ratios (ζ) from 0.03 to 0.56 were identified. The resulting phantoms were tested in two different elastographic breast cancer diagnostic modalities. A significant contrast was successfully identified between healthy tissues and cancerous tumors both in Magnetic Resonance Elastography (MRE) and Digital Image Elasto-tomography (DIET). Conclusions: The phantoms presented promise aid to researchers in elastographic imaging modalities for breast cancer detection and provide a foundation for silicone based phantom materials for mimicking soft tissues of other human organs.