Breast imaging using ultrasound tomography: From clinical requirements to system design

Ultrasound tomography (UST) is a breast imaging modality that is radiation free, operator independent, and does not involve breast compression. In the UST system under consideration, the breast is surrounded by a transducer ring that moves along the coronal axis from the chest wall to the nipple region. The deployment of UST in a clinical setting is technically challenging from three major standpoints: acquisition speed, storage capability, and computational requirements. Data acquisition must be fast to maximize patient throughput and minimize image registration artifacts. Unlike traditional ultrasound, hundreds of gigabytes of data must be acquired, buffered, and processed to image various characteristics of breast tissues such as sound speed, attenuation, and reflectivity. The tomographic image reconstruction methods are non-linear, iterative algorithms with significant computational complexity. Moreover, the scanner hosting the acquisition and reconstruction components must satisfy stringent cost, power, and size requirements. For decades, the above constraints have hindered the practicality of UST in a clinical scenario. We describe the design of a UST system that addresses the relevant clinical requirements as a means to demonstrate the feasability of UST deployment in a clinical setting.