Development of breast-mimicking phantoms for use in optical coherence elastography.

Significance: Optical coherence elastography (OCE) is an emerging technique for mapping tissue mechanical properties into an image, known as an elastogram, with microscale resolution. Although system characterization phantoms are widely used in OCE development, there is a critical need for tissue-mimicking phantoms that can more accurately replicate the complex structural and mechanical properties of tissues, particularly for validating clinical applications, such as in breast cancer.

Aim: We aim to investigate the effects of tissue-like structures on elastogram formation in a controlled environment by developing and characterizing two types of breast tissue-mimicking phantoms, replicating invasive ductal carcinoma (IDC) morphology and the other mimicking breast ductal networks.

Approach: We present a comprehensive methodology for fabricating breast-mimicking phantoms using optical coherence tomography and ductography images to provide information on tissue structure. The method employs 3D-printed molds, casting different silicone materials for IDC-mimicking phantoms and implementing a dissolving mold technique to create duct-mimicking phantoms, which can be tested in both empty and fluid-filled states.

Results: The IDC-mimicking phantom successfully replicates structural features as small as $100\mu m$ , revealing complex mechanical behaviors at tissue interfaces, including strain concentrations where tissues of different stiffness interact. The duct-mimicking phantom demonstrates distinct mechanical responses between configurations, with hollow ducts creating sharp discontinuities at boundaries, whereas fluid-filled ducts exhibit more gradual transitions in mechanical properties.

Conclusions: Our methodology demonstrates the capability to fabricate breast tissue-mimicking phantoms that reproduce both the structural and mechanical properties of breast tissue, providing a controlled environment for investigating OCE performance and understanding how tissue architecture influences elastogram formation, particularly at interfaces among different tissue types.