ABSTRACT
PURPOSE: To describe and evaluate a method of tomosynthesis breast imaging with a full-field digital mammographic system. MATERIALS AND METHODS: In this tomosynthesis method, low-radiation-dose images were acquired as the x-ray source was moved in an arc above the stationary breast and digital detector. A step-and-expose method of imaging was used. Breast tomosynthesis and conventional images of two imaging phantoms and four mastectomy specimens were obtained. Three experienced readers scored the relative lesion visibility, lesion margin visibility, and confidence in the classification of six lesions. RESULTS: Tomosynthesis image-reconstruction algorithms allow tomographic imaging of the entire breast from a single arc of the x-ray source and at a radiation dose comparable with that in single-view mammography. Except for images of a large mass in a fatty breast, the tomosynthesis images were superior to the conventional images. CONCLUSION: Digital mammographic systems make breast tomosynthesis possible. Tomosynthesis may improve the specificity of mammography with improved lesion margin visibility and may improve early breast cancer detection, especially in women with radiographically dense breasts.
Subject(s)
Mammography , Radiographic Image Enhancement , Female , Humans , In Vitro Techniques , Phantoms, ImagingABSTRACT
A 1 mm x 1 mm nematic liquid-crystal three-terminal device for optical beam forming (focusing/spoiling) is fabricated. A thin-film-resistor network on the device substrate layer is used to control the voltages on the 98 internal lens electrodes by use of only one variable external driver. By using a high-resistance thin-film layer of amorphous silicon under the 98-element parallel electrode structure layer, we generate a near-continuous index perturbation to form a cylindrical lens. The focal length of this lens is continuously variable from inifinity to 12 cm by use of a variable 1-4-V-peak 1-kHz square-wave external terminal control signal.
