Novel breast imaging techniques using transmission ultrasound

Abstract

Despite several limitations, ultrasound is an important adjunctive modality for detection and management of breast cancer, but it is not recommended for screening. We have explored novel approaches to breast imaging using transmission ultrasound to provide very large image fields, differentiation of breast masses, and improved detection of microcalcifications without the use of ionizing radiation or compression. One method uses a circular array and an iterative Born technique to reconstruct scatter properties in a series of coronal slices through the breast. The second method is based on acoustical holography in which an interference pattern is formed by combining a transmitted field with a reference beam. The signal is converted to the optical domain using a coherent laser detector. This latter method provides real-time images in a large fluoroscopy-like format but with pronounced soft tissue edge definition. A set of large acoustic lenses provides zoom and focal plane control for magnified imaging with enhanced resolution and depth. Both systems have undergone preliminary investigation in large groups of patients with known abnormalities to assess their suitability for detection and characterization of breast disease and to provide accurate guidance for biopsy or tumor ablation. Results of laboratory and clinical findings will be presented.