Ultrasound tomography dedicated to ANAtomical breast inspection

The main goal of ultrasound tomography (UT) is to provide both a high contrast imaging and a multi-parametric imaging. Within the frame of soft-tissue imaging, we focus our application to breast inspection for early stage cancer detection. Conforming with breast anatomy, ANAIS (ANAtomical Imaging and Interventional System) prototype is designed including a semicircular antenna which enables imaging of ductolobular structures sensitive to cancer initiation. The 200-mm diameter half-ring transducer contains 1024 elements with 3-MHz center frequency and 2.25-MHz (-6 dB) bandwidth. Chirp excitation is used to improve contrast with pulse compression method. Performed with a needle hydrophone, calibration studies yield system characteristics such as field distribution or transducer element localization. Taking advantage of a near field reconstruction algorithm, tomographic images of thin wire and of breast anthropomorphic phantom (CIRS) are presented. The low frequency approach and the high density of the ring antenna provide interesting results that, as we expect, may still be enhanced.