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Time-of-flight tomography within the first order Born approximation has an inherent limitation on spatial and contrast resolution. The deviation of the propagation path from a straight line mainly caused by refraction is dependent on the speed of sound distribution. Some examples in published literature simulate cylindrical phantoms lying at the center of rotation. This paper investigates the effect...
One of the central desiderata of the preclinical cancer research is a reliable imaging system making the noninvasive characterization of different tissue types possible. While spatially resolved reconstruction of speed of sound and acoustic attenuation is known to be significantly useful in differentiating between different tissue changes in human female breast, the two parameters may also contribute...
For full angle spatial compounding, an object is imaged in one plane from multiple aspect angles and the obtained images are superimposed in correct geometric orientation. Thus, information about the distribution of speed of sound inside the object is required for a correction of individual images with respect to transit time and refraction of the ultrasonic waves. In this paper, we present a method...
Under a contract with the National Cancer Institute, we have developed a research interface to an ultrasound system. This ultrasound research interface (URI) is an optional feature providing several basic capabilities not normally available on a clinical scanner. The URI can store high-quality beamformed radio-frequency data to file for off-line processing. Also, through an integrated user interface,...
Full angle spatial compounding is of interest for imaging small organs (breast, testicles) and small animals. Besides phase aberration and out of plane refraction the variations in speed of sound, usually assumed to be constant, also cause registration error. This error may be negligible regarding the visual appraisal of B-mode images; its effect on spatial compounding of the individual scans may,...
In order to decrease artifacts from tissue, contrast enhanced perfusion imaging is usually conducted using low transmit power (low MI). However, with low MI echo signals from deeper structures are weak and often miss higher harmonics due to attenuation. Furthermore, shadowing artifacts may occur as a result of high concentration of contrast agent. Imaging an object (e.g. female breast) from multiple...
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