Ultrasonic Computed Tomography of the Breast Using Linear Arrays
Date Issued
2004
Date
2004
Author(s)
Huang, Sheng-Wen
DOI
en-US
Abstract
The performance of B-mode ultrasound in the clinical detection of breast cancer is often limited by poor contrast resolution. Contrast mechanisms based on alternative tissue characteristics, such as direct estimation of sound velocities and attenuation coefficients in different tissues, may offer additional diagnostic information. An approach based on limited-angle transmission tomography for reconstruction of the sound velocity distribution and attenuation coefficient distribution in the breast is proposed in this thesis. The imaging setup is similar to that of x-ray mammography. With this setup, the time-of-flight data and the attenuation data are acquired by a linear array positioned at the top of the compressed breast that both transmits and receives, and a metal plate is placed at the bottom as a reflector. Such a setup can be easily integrated with a B-mode system so that the acoustic data for all of the B-mode image, the sound velocity distribution, and the attenuation coefficient distribution can be simultaneously acquired. However, the acquired data are incomplete, and this results in inaccurate sound velocity estimation and attenuation coefficient estimation. In order to improve the estimation accuracy, a new reconstruction algorithm based on a convex programming formulation was developed. This improvement is mainly attributable to the proposed algorithm successfully incorporating information from the B-mode image of the same object. Furthermore, a technique based on the angular spectrum method was developed to compensate the effects of refraction on the attenuation data using the information on sound velocity distribution. Simulation results and experimental results demonstrate that the proposed approach to limited-angle transmission tomography using linear arrays is feasible. Both the sound velocity image and the attenuation coefficient image can be used to complement conventional B-mode image to enhance the detection of breast cancer.
Subjects
乳房腫瘤
斷層掃描
衰減係數
乳癌
聲速
超音波
attenuation coefficient
computed tomography
breast cancer
ultrasound
sound velocity
SDGs
Type
thesis
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